Selasa, 23 Februari 2010
Selasa, 16 Februari 2010
Tuning gitar
Tuning gitar merupakan proses menentukan frekuensi dan menyelaraskan frekuensi antar senar hingga menghasilkan nada standar. Pada gitar proses ini dilakukan dengan mengatur ketegangan senar melalui pemutar (tuning machine) yang ada di kepala (Head) gitar.
Tuning standar pada gitar yaitu E-A-D-G-B-E (mulai dari senar 6-5-4-3-2-1). Untuk menghasilkan frekuensi nada standart yang dapat di gunakan untuk men-tuning (stem) gitar anda diantaranya dengan menggunakan sebuah Chromatic Tuner elektronik, mencocokan frekuensi (nada yang di hasilkan) dengan alat musik lain maupun melakukan tuning dengan cara manual.
Tuning menggunakan chromatic tunner :
Dengan cara ini kita hanya perlu menghubungkan gitar kita ke perangkat chromatic tuner (bisa juga dengan hanya di dekatkan saja, tergantung perangkat tuning yang anda gunakan), lalu atur ketegangan senar yang akan anda tuning melalui pemutar (tuning machine) hingga perangkat chromatic tuner menghasilkan nada yang sesuai. Lakukan juga pada senar senar berikutnya
Tuning dengan membandingkan nada alat musik lain
Sebagai contoh saya akan memberikan cara ilustrasi mentuning gitar dengan cara membandingkan nada pada alat musik piano.
Denagn cara ini anda hanya membandingkan nada hingga menghasilkan frekuensi nada yang sama pada piano, Putarlah tuning machine pada senar yang akan anda stem dan babdingkan dengan nada yang di hasilkan oleh perangkat piano, lakukan juga untuk senar-senar lainnya. Ilustrasinya kira2 seperti gambar berikut :
Tuning dengan cara Manual :
Ini merupakan cara yang termudah dan termurah ( karena anda tidak harus membeli Cromatic tuner maupun sebuah Piano untuk mentuning gitar anda). Anda hanya membutuhkan insting mendengarkan nada dengan baik, silahkan berlatih agar terbiasa. Anda dapat memulai dengan cara :
* Mengatur tuner machine pada senar 1 (open string) hingga menghasilkan nada E
* Setelah itu atus senar 2 dan tekan fret ke 5 hingga hasilnya akan sama dengan nada senar 1 (open string – nada e)
* Lanjutkan dengan atur senar 3 dan tekan fret 4 hingga hasilnya akan sama dengan nada senar 2 (open string – nada B)
* Lanjutkan dengan atur senar 4 dan tekan fret 5 hingga hasilnya akan sama dengan nada senar 3 (open string – nada G)
* Lanjutkan dengan atur senar 5 dan tekan fret 5 hingga hasilnya akan sama dengan nada senar 4 (open string – nada D)
* Lanjutkan dengan atur senar 6 dan tekan fret ke 5 hingga hasilnya akan sama dengan nada senar 5 (open string – nada A)
Silahkan lihat ilustrasi gambar diatas, Apabila anda telah berhasil maka gitar anda akan menghasilkan nada E > senar 6, nada A > senar 5, nada D > senar 4, nada G > senar 3, nada B > senar 2 dan terakhir nada e > senar 1.
semoga bermanfaat dan selamat mencoba.
Rf: http://forum.detiksurabaya.com/showthread.php?p=22075
Tuning standar pada gitar yaitu E-A-D-G-B-E (mulai dari senar 6-5-4-3-2-1). Untuk menghasilkan frekuensi nada standart yang dapat di gunakan untuk men-tuning (stem) gitar anda diantaranya dengan menggunakan sebuah Chromatic Tuner elektronik, mencocokan frekuensi (nada yang di hasilkan) dengan alat musik lain maupun melakukan tuning dengan cara manual.
Tuning menggunakan chromatic tunner :
Dengan cara ini kita hanya perlu menghubungkan gitar kita ke perangkat chromatic tuner (bisa juga dengan hanya di dekatkan saja, tergantung perangkat tuning yang anda gunakan), lalu atur ketegangan senar yang akan anda tuning melalui pemutar (tuning machine) hingga perangkat chromatic tuner menghasilkan nada yang sesuai. Lakukan juga pada senar senar berikutnya
Tuning dengan membandingkan nada alat musik lain
Sebagai contoh saya akan memberikan cara ilustrasi mentuning gitar dengan cara membandingkan nada pada alat musik piano.
Denagn cara ini anda hanya membandingkan nada hingga menghasilkan frekuensi nada yang sama pada piano, Putarlah tuning machine pada senar yang akan anda stem dan babdingkan dengan nada yang di hasilkan oleh perangkat piano, lakukan juga untuk senar-senar lainnya. Ilustrasinya kira2 seperti gambar berikut :
Tuning dengan cara Manual :
Ini merupakan cara yang termudah dan termurah ( karena anda tidak harus membeli Cromatic tuner maupun sebuah Piano untuk mentuning gitar anda). Anda hanya membutuhkan insting mendengarkan nada dengan baik, silahkan berlatih agar terbiasa. Anda dapat memulai dengan cara :
* Mengatur tuner machine pada senar 1 (open string) hingga menghasilkan nada E
* Setelah itu atus senar 2 dan tekan fret ke 5 hingga hasilnya akan sama dengan nada senar 1 (open string – nada e)
* Lanjutkan dengan atur senar 3 dan tekan fret 4 hingga hasilnya akan sama dengan nada senar 2 (open string – nada B)
* Lanjutkan dengan atur senar 4 dan tekan fret 5 hingga hasilnya akan sama dengan nada senar 3 (open string – nada G)
* Lanjutkan dengan atur senar 5 dan tekan fret 5 hingga hasilnya akan sama dengan nada senar 4 (open string – nada D)
* Lanjutkan dengan atur senar 6 dan tekan fret ke 5 hingga hasilnya akan sama dengan nada senar 5 (open string – nada A)
Silahkan lihat ilustrasi gambar diatas, Apabila anda telah berhasil maka gitar anda akan menghasilkan nada E > senar 6, nada A > senar 5, nada D > senar 4, nada G > senar 3, nada B > senar 2 dan terakhir nada e > senar 1.
semoga bermanfaat dan selamat mencoba.
Rf: http://forum.detiksurabaya.com/showthread.php?p=22075
Rabu, 10 Februari 2010
install cacti di windows
Installations
1. Download and install the following pieces of software:
* (optional) Apache and install it to c:\apache or c:\apache2. Make sure to install it as a service.
* Cacti and extract it to the root of your web server directory. Typically c:\inetpub\wwwroot\ or c:\apache2\.
* Cactid and extract it to c:\cactid.
* RRDTool and extract it to c:\rrdtool.
* PHP 4.3.6+ or 5.x and extract it to c:\php.
* MySQL 4.0 or MySQL 4.1. 5.0 is not supported unless you run it in compatibility mode and with the MySQL 5 patch. Install it to c:\mysql.
* (optional) Cygwin. Download setup.exe and keep it around until later used in the document.
* (optional) Net-SNMP and install to c:\net-snmp.
Configure PHP
1.If using PHP 4, move the files in c:\php\dlls to c:\php.
2.Add the following to your Windows PATH environment variable c:\php. The Windows
path can be accessed via the Control Panel at: System | Advanced | Environment Variables | System Variables..
3.Add the following two new environment variables to your system using the procedure above: PHPRC=c:\php.
1. If using PHP 4, create this variable: MIBDIRS=c:\php\mibs
2. If using PHP 5, create this variable: MIBDIRS=c:\php\extras\mibs
4.If using PHP 4.3.5 or less (not recommended), create the following directory c:\tmp.
5.Rename the file c:\php\php.ini.dist to php.ini, and make the following changes to it:
If using PHP 4 uncomment the following lines:
extension_dir = c:\php\extensions
extension=php_snmp.dll
extension=php_sockets.dll
cgi.force_redirect = 0
If using PHP 5 uncomment the following lines:
extension_dir = c:\php\ext
extension=php_mysql.dll
extension=php_snmp.dll
extension=php_sockets.dll
cgi.force_redirect = 0
If using PHP 4.3.5 or less include the following line. If using 4.3.6 or greater, you should remove this line if present.
session.save_path=c:\tmp
6.If you have had previous versions of PHP installed, you had likely moved the PHP system files to in the Windows directory structure. If so, you will have to remove those files. Please review your PHP installation documentation for instructions on removing those files.
7. If you want to allow template importing, uncomment the following line:
file_uploads = On
8. Give the user who will be running the scheduled task, modify rights to:
1. If using PHP 4: c:\php\mibs\.index
2. If using PHP 5: c:\php\extras\mibs\.index
Configure the Webserver (Apache)
1.Make sure you have stopped any IIS web servers before you proceed with Apache installation.
2.If you are using Apache 1.3.x, installation of PHP 5 is not recommended. If using PHP 4, add the following lines to your httpd.conf file in the c:\apache\conf directory:
LoadModule php4_module c:\php\sapi\php4apache.dll
AddModule mod_php4.c
AddType application/x-httpd-php .php
DirectoryIndex index.html index.htm index.php
3.If you are using Apache 2.x, add the following lines to your httpd.conf file in the c:\apache2\conf directory:
If using PHP 4, then add the following lines:
LoadModule php4_module c:\php\sapi\php4apache2.dll
AddType application/x-httpd-php .php
DirectoryIndex index.html index.htm index.php
If using PHP 5, then add the following lines:
LoadModule php5_module c:\php\php5apache2.dll
AddType application/x-httpd-php .php
DirectoryIndex index.html index.htm index.php
Configure the Webserver (IIS)
1.Start the Internet Information Services (IIS) Manager, right click on Default Web Site (in most cases) and select Properties.
2.Under the Home Directory tab, select Configuration and click Add. Browse to the path of php4isapi.dll or php5isapi.dll, and type in .php as the extension.
IIS6: Enable All Verbs and Script Engine.
3.Under the ISAPI Filters tab, click Add and browse to the php4isapi.dll or
php5isapi.dll file. Name the filter "php" and click OK.
4.Under the Documents tab, add index.php to the top of the list.
5. If using IIS6, go to Web Service Extensions and add a new Web Service Extension. Name the extension "php", click Add and browse to the php4isapi.dll or php5isapi.dll file, enable Set Extension status to Enable, and click OK.
6. Under the Default Web Site, right click on Cacti and select Properties.
7. Under the Directory tab, click the Write checkbox..
8. Give the IUSR_XXXX and IIS_WPG users read & execute permissions to the file %windir%\system32\cmd.exe. They will also need read permissions on/cacti/ and its subfolders.
9. IIS6: Give the IIS_WPG user modify permissions to the folders /cacti/log and /cacti/rrd.
10.Completely stop and start the IIS service using the following commands:
net stop iisadmin
net start w3svc
Install Cygwin (optional)
1. Installing a single instance of Cygwin, and using it for all applications that require it is recommended so you do not have different versions of the Cygwin dlls laying around on your system, which can cause conflicts.
2. Run setup.exe you previously downloaded.
3. Once you reach the portion of setup entitled Select Packages, install the following:
Base (whole thing)
Libs
libart_lgpl
libfreetype26
libpng12
zlib
Utils
patch
Web
wget
4. Add c:\cygwin\bin to your system path.
5. Move setup.exe to c:\cygwin for future use.
Install RRDTool
1. If you have Cygwin installed, remove the DLL files from the c:\rrdtool directory.
Configure MySQL
1.Start MySQL by running c:\mysql\bin\winmysqladmin.exe.
2.Set a password for the root user
shell> cd mysql\bin
shell> mysqladmin --user=root password somepassword
shell> mysqladmin --user=root --password reload
3.Create the MySQL database:
shell> mysqladmin --user=root --password create cacti
4.Import the default Cacti database:
shell> mysql --user=root --password cacti < c:\apache2\htdocs\cacti\cacti.sql
5.Optional: Create a MySQL username and password for Cacti.
shell> mysql --user=root --password mysql
mysql> GRANT ALL ON cacti.* TO cactiuser@localhost IDENTIFIED BY 'somepassword';
mysql> flush privileges;
6. If you're running MySQL 4.1 then you will need to apply the old password trick for user authentication to work with Cacti.
Stop the MySQL service and add the following to Start Parameter field. Start it again once it has been added.
--old-passwords
You will also need to update the cactiuser account with the old password style:
shell> UPDATE mysql.user SET Password = OLD_PASSWORD('cactipw') WHERE Host = 'localhost' AND User = 'cactiuser';
mysql> FLUSH PRIVILEGES;
7. If you're running MySQL 5, then you will need to run it in compatibility mode by specifying the following in the Start Parameter field for the MySQL service:
--sql-mode=MYSQL40
Install Net-SNMP
1.If you plan to use any hosts with SNMP v2c support, you must download and install the Net-SNMP libraries. Net-SNMP provides installers to install their product. However, caution must be taken not to use long file names as Cacti does not support them in this version. We suggest you install Net-SNMP in a directory such as c:\net-snmp.
Configure Cactid
1.Modify the cactid.conf file in c:\cactid to include the following statements.
DB_Host IP_Address or Hostname (not localhost)
DB_Database cacti
DB_User cactiuser
DB_Password cactipw
All other pre 0.8.6 settings are obsolete. Cactid may not complain if you leave them in, but they are not longer required. Cactid now comes with a binary distribution. Therefore, a basic installation of Cygwin is not longer required, but suggested to help maintain dll version conflicts.
2.If you have Cygwin installed, remove the DLL files and the SH.EXE file from the c:\cactid directory.
Configure Cacti
1.Edit/cacti/include/config.php and specify the MySQL user, password and database for your Cacti configuration.
$database_default = "cacti";
$database_hostname = "localhost";
$database_username = "cactiuser";
$database_password = "cactipw";
2.Point your web browser to:
http://your-server/cacti/
Log in the with a username of admin and password of admin. You will be required to change this password immediately.
Once logged in, you must go to Settings->Paths and verify/update your paths to point to the correct locations. Recommended examples are posted below. If you plan on using Cactid, then it is very important that your all your paths and scripts use forward slashes.
PHP Binary Path:
If using PHP 4, you should change this to:
c:/php/php.exe
If using PHP 5, you should change this to:
c:/php/php.exe
RRDTool Binary Path:
c:/rrdtool/rrdtool.exe
RRDTool Default Font Path:
c:/windows/fonts/arial.ttf
RRDTool Version:
Select the appropriate version
SNMPGET, SNMPWALK Paths:
c:/net-snmp/bin/snmpget.exe
c:/net-snmp/bin/snmpwalk.exe
Cacti Logfile Path:
c:/mycacti/website/cacti/log/cacti.log
Cactid Path:
c:/cactid/cactid.exe
3. Click on Devices. Delete Localhost, since it's set up to use the Linux host template. In the upper right corner, click on Add. Fill in the following information and then click Add.
Description: localhost
Hostname: localhost
Host Template: Windows 2000/XP
4. You should now be looking at the localhost device screen. Right under it's name, there should be some SNMP information listed, if not you should double check the SNMP settings on the server and firewall settings. In the upper right-hand corner, click on Create Graphs for this Host. On the following screen, select a disk partition and network interface. At the bottom of the page, click on Create.
5. Log into the user account you'll be using for the scheduled task and verify starting a Cacti polling cycle works. Do this by running the following from the command prompt:
php c:\\cacti\poller.php
The output should look something like this:
C:\>php c:\inetpub\wwwroot\cacti\poller.php
OK u:0.00 s:0.06 r:1.32
OK u:0.00 s:0.06 r:1.32
OK u:0.00 s:0.16 r:2.59
OK u:0.00 s:0.17 r:2.62
10/28/2005 04:57:12 PM - SYSTEM STATS: Time:4.7272 Method:cmd.php Processes:1 Threads:N/A Hosts:1 HostsPerProcess:2 DataSources:4 RRDsProcessed:2
After this has ran once, you should have cacti.log in /cacti/log/ and rrd files in /cacti/rra/.
6.You are going to need to schedule a task while logged on as an Administrator account, so poller.php can run every 5 minutes. Make sure the Task Scheduler service is started and follow the steps below to begin.
1.Select Start --> Settings --> Control Panel and double click on Scheduled Tasks.
2.Double click on Add Scheduled Task.
3.Click Next and Browse on the following screen. Find c:\php and select php.exe. If using PHP 5 with Cacti 0.8.6f or earlier, use php-win.exe instead. Choose Daily on and click Next.
4.Click Next again without changing the time or date settings.
5.When entering a username and password make sure the user has modify access to the following directories:
c:\\cacti\rra\
c:\\cacti\log\
Make sure the user has read, and execute access to the following directories:
c:\php\
c:\\cacti\
6.Click Next and Finish to close the wizard.
7.Right click on the task you just created, and select Properties.
8.Select the Schedule tab.
9.Make sure Daily is selected and click the Advanced button.
10.Check the Repeat checkbox, set the repetition for every 5 minutes, set the duration for 24 hours, and check the If the task is still running, stop it at this time checkbox.
11.Click Ok
12.In the Run textbox enter the following text making sure to use the appropriate paths.
c:\php\php.exe c:\\cacti\poller.php
The start in box should say c:\\cacti.
Apply Patches
1. There are two methods of applying patches to Cacti:
1. If you have Cygwin installed, then the patch instructions which use wget and patch, will work.
2. The other method requires you to visit http://www.cacti.net/downloads/patches//pre-patched/ and manually download and replace the patched files.
2. You might need to reapply file/folder security on the files patched. Double check they are correct.
Tweaking
There are several things you can do to speed up your Cacti web server. It's suggested that you only apply these after you have a fully functional Cacti installation.
1. Switch the polling agent in Cacti from cmd.php to Cactid.exe. Go to Settings | Poller | Type.
2. Install the Zend Optimizer for PHP.
3. Set up the query cache in MySQL. Read about how to properly configure the settings. You will need to stop the MySQL service when you edit c:\mysql\my.ini and put in the following:
#The memory allocated to store results from old queries.
query_cache_size=16M
#Don't cache results that are bigger than this.
query_cache_limit=1M
#Query cache type to use.
query_cache_type=1
4. Install FastCGI, which can offer x4 to x8 improvement (for IIS users at least).
5. An extensive list of other optimizations for PHP and MySQL can be found over at phplens.com.
Chapter 4. Upgrading Cacti
1.Backup the old Cacti database.
shell> mysqldump -l --add-drop-table cacti > mysql.cacti
Note: You will probably have to specify the -u and -p flags for the MySQL username and password. This user must have permission to read from Cacti's database or you will end up with an empty backup.
2.Backup the old Cacti directory.
shell> mv cacti cacti_old
3.Extract the distribution tarball.
shell> tar xzvf cacti-version.tar.gz
4.Rename the new Cacti directory to match the old one.
shell> mv cacti-version cacti
5.Edit include/config.php and specify the MySQL user, password and database for your Cacti configuration.
$database_type = "mysql";
$database_default = "cacti";
$database_hostname = "localhost";
$database_username = "cactiuser";
$database_password = "cacti";
6.Copy the *.rrd files from the old Cacti directory.
shell> cp cacti_old/rra/* cacti/rra/
7.Copy any relevant custom scripts from the old Cacti directory. Some script are updated between versions. Therefore, make sure you only over write if the scripts either don't exist or are newer than the distribution's.
shell> cp -u cacti_old/scripts/* cacti/scripts/
8.Copy any relevant custom resource XML files from the old Cacti directory. Some resource XML files are updated between versions. Therefore, make sure you only over write if the XML files either don't exist or are newer than the distribution's.
shell> cp -u -R cacti_old/resource/* cacti/resource/
9.Set the appropriate permissions on Cacti's directories for graph/log generation. You should execute these commands from inside Cacti's directory to change the permissions.
shell> chown -R cactiuser rra/ log/
(Enter a valid username for cactiuser, this user will also be used in the next step for data gathering.)
10.Point your web browser to:
http://your-server/cacti/
Follow the on-screen instructions so your database can be updated to the new version.
II. Basics
Table of Contents
5. Principles of Operation
6. Graph Overview
7. How to Graph Your Network
8. Viewing Graphs
9. User Management
Chapter 5. Principles of Operation
Table of Contents
Data Retrieval
Data Storage
Data Presentation
Cacti operation may be divided into three different tasks:
Figure 5-1. Principles of Operation
Chapter 3. Installing Under Windows
Data Retrieval
First task is to retrieve data. Cacti will do so using its Poller. The Poller is executed from the operating system's scheduler, e.g. crontab for Unix flavored OSes.
In current IT installations, you're dealing with lots of devices of different kind, e.g. servers, network equipment, appliances and the like. To retrieve data from remote targets/hosts, cacti will mainly use the Simple Network Management Protocol SNMP. Thus, all devices capable of using SNMP will be eligible to be monitored by cacti.
Later on, we demonstrate how to extend cacti's capabilities of retrieving data to scripts, script queries and more.
Chapter 6. Graph Overview
Almost everything in Cacti is somehow related to a graph. At any time, you can list all available graphs by clicking on the Graph Management menu item. While it is possible to manually create graphs through this screen, new users should follow the instructions provided in the next chapter for creating new graphs in Cacti.
For users that are familiar with RRDTool , you will immediately recognize that a graph in Cacti is closely modeled after RRDTool's graphs. This makes sense since Cacti provides a user friendly interface to RRDTool without requiring users to understand how RRDTool works. With this in mind, every graph in Cacti has certain settings and at least one graph item associated with it. While graph settings define the overall properties of a graph, the graph items define the data that is to be represented on the graph. So the graph items define which data to display and how it should displayed, and also define what should be displayed on the legend.
Each graph and graph item has a set of parameters which control various aspects of the graph. Fortunately through the use of graph templates, it is not necessary to understand the function of each field to create graphs for your network. When you are ready to take on the task of creating your own graph templates, extensive field descriptions for both graphs and graph items are provided in that section of the manual.
Chapter 7. How to Graph Your Network
Table of Contents
Creating a Device
Creating the Graphs
At this point, you probably realize that graphing is Cacti's greatest strength. Cacti has many powerful features that provide complex graphing and data acquisition, some which have a slight learning curve. Do not let that stop you however, because graphing your network is incredibly simple.
The next two sections will outline the two basic steps which are typically required to create graphs for most devices.
Creating a Device
The first step to creating graphs for your network is adding a device for each network device that you want to create graphs for. A device specifies important details such as the network hostname, SNMP parameters, and host type.
To manage devices within Cacti, click on the Devices menu item. Clicking Add will bring up a new device form. The first two fields, Description and Hostname are the only two fields that require your input beyond the defaults. If your host type is defined under the host template dropdown, be sure to select it here. You can always choose "Generic SNMP-enabled Host" if you are just graphing traffic or "None" if you are unsure. It is important to remember that the host template you choose will not lock you into any particular configuration, it will just provide more intelligent defaults for that type of host.
Figure 7-1. Adding a New Device
The field definitions are as follows
Table 7-1. Device Field Definitions
Field Description
Description This description will show up in the first column of the device list. You may refer to it e.g. in graph titles
Hostname Either an IP address or a hostname. The hostname will be resolved using the standard host resolving mechanisms, e.g. Dynamic Name Services (DNS)
Host Template A Host Template is a container for a list of graph templates that will be related to this host.
Notes New with cacti 0.8.7. Add notes to a host to add arbitrary text.
Disable Host Exclude this host from being polled. This is of particular value, if a device is no longer available, but should be kept e.g. as a reference.
Availability/Reachability Options
Downed Device Detection
NONE: Deactivate downed host detection
PING and SNMP: perform both tests
SNMP: verify SNMP check on OID .1 and .1.3
ICMP: perform a ping test, see below
Ping Method
Available only for "PING and SNMP" or "PING"
ICMP: perform ICMP tests. Requires permissions
UDP: perform a UDP test
TCP: perform a TCP test
Ping Port
Available only for UDP/TCP PING test types.
Please define the port to be tested here. Make sure, that no firewall intercepts the tests
Ping Timeout Value After this time, the test fails. Measured in units of milliseconds
Ping Retry Count The number of times Cacti will attempt to ping a host before failing.
SNMP Options
SNMP Version
Version 1: Use SNMP Version 1. Be aware, that 64bit counters are not supported in this SNMP version
Version 2: Referred to as SNMP V2c in most SNMP documentations
Version 3: SNMP V3, supporting authentication and encryption
SNMP Community SNMP read community for this device.
SNMP Port Enter the UDP port number to use for SNMP (default is 161).
SNMP Timeout The maximum number of milliseconds Cacti will wait for an SNMP response (does not work with php-snmp support).
Maximum OID's Per Get Request
This is a performance feature. Specifies the number of OID's that can be obtained in a single SNMP Get request.
NOTE: This feature only works when using Spine
NOTE: Some devices do not support values > 1
Security Options for SNMP V3
SNMP Username The username of an SNMP V3 createUser statement or equivalent
SNMP Password The authpassphrase of an SNMP V3 createUser statement or equivalent
SNMP Auth Protocol The authentication type of an SNMP V3 createUser statement or equivalent. Select either MD5 or SHA. This entry defaults to MD5.
SNMP Privacy Passphrase The privacy passphrase of an SNMP V3 createUser statement or equivalent.
SNMP Privacy Protocol The privacy protocol of an SNMP V3 createUser statement or equivalent. Select either DES or AES. This entry defaults to DES.
SNMP Context When using the View-Based Access Control Model (VACM), it is possible to specify an SNMP Context when mapping a community name to a security name with a com2sec directive, with the group directive and the access directive. This allows for defining special access models. If using such a parameter with your target's SNMP configuration, specify the context name to be used to access that target here.
After saving your new device, you should be redirected back to the same edit form with some additional information. If you configured SNMP for this host by providing a valid community string, you should see various statistics listed at the top of the page. If you see "SNMP error" instead, this indicates an SNMP problem between Cacti and your device.
Towards the bottom of the page there will be two addition boxes, Associated Data Queries, and Associated Graph Templates. If you selected a host template on the previous page, there will probably be a few items in each box. If there is nothing listed in either box, you will need to associate at least one data query or graph template with your new device or you will not be able to create graphs in the next step. If no available graph template or data query applies to your device, you can check the Cacti templates repository or create your own if nothing currently exists.
A Word About SNMP
The SNMP version that you choose can have a great effect on how SNMP works for you in Cacti. Version 1 should be used for everything unless you have reason to choose otherwise. If you plan on utilizing (and your device supports) high-speed (64-bit) counters, you must select version 2. Starting with Cacti 0.8.7, version 3 is fully implemented.
The way in which Cacti retrieves SNMP information from a host has an effect on which SNMP-related options are supported. Currently there are three types of SNMP retrieval methods in Cacti and are outlined below.
Table 7-2. SNMP Retrieval Types
Type Description Supported Options Places Used
External SNMP Calls the net-snmp snmpwalk and snmpget binaries that are installed on your system. All SNMP options Web interface and PHP poller (poller.php)
Internal SNMP (php-snmp) Uses PHP's SNMP functions which are linked against net-snmp or ucd-snmp at compile time. Version 1 Only (Community and Port) Web interface and PHP poller (poller.php)
Spine SNMP Links directly against net-snmp or ucd-snmp and calls the API directly. All SNMP options C-Based Poller (Spine)
SNMP V3 Options Explained
SNMP supports authentication and encryption features when using SNMP protocol version 3 known as View-Based Access Control Model (VACM). This requires, that the target device in question supports and is configured for SNMP V3 use. In general, configuration of V3 options is target type dependant. The following is cited from man snmpd.conf concerning user definitions
[ SNMPv3 Users
createUser [-e ENGINEID] username (MD5|SHA) authpassphrase [DES|AES] [privpassphrase]
MD5 and SHA are the authentication types to use. DES and AES are the privacy
protocols to use. If the privacy passphrase is not specified, it is assumed
to be the same as the authentication passphrase. Note that the users created will
be useless unless they are also added to the VACM access control tables
described above.
SHA authentication and DES/AES privacy require OpenSSL to be installed and the
agent to be built with OpenSSL support. MD5 authentication may be used without
OpenSSL.
Warning: the minimum pass phrase length is 8 characters.]
VACM directives are explained from man snmpd.conf as follows
[ VACM Configuration
The full flexibility of the VACM is available using four configuration directives -
com2sec, group, view and access. These provide direct configuration of the underlying
VACM tables.
com2sec [-Cn CONTEXT] SECNAME SOURCE COMMUNITY
map an SNMPv1 or SNMPv2c community string to a security name - either from a
particular range of source addresses, or globally ("default"). A restricted
source can either be a specific hostname (or address), or a subnet -
represented as IP/MASK (e.g. 10.10.10.0/255.255.255.0), or IP/BITS
(e.g. 10.10.10.0/24), or the IPv6 equivalents.
The same community string can be specified in several separate directives
(presumably with different source tokens), and the first source/community
combination that matches the incoming request will be selected. Various
source/community combinations can also map to the same security name.
If a CONTEXT is specified (using -Cn), the community string will be mapped
to a security name in the named SNMPv3 context. Otherwise the default
context ("") will be used.
group GROUP {v1|v2c|usm} SECNAME
maps a security name (in the specified security model) into a named group.
Several group directives can specify the same group name, allowing a single
access setting to apply to several users and/or community strings.
Note that groups must be set up for the two community-based models separately -
a single com2sec (or equivalent) directive will typically be accompanied by two
group directives.
view VNAME TYPE OID [MASK]
defines a named "view" - a subset of the overall OID tree. This is most commonly
a single subtree, but several view directives can be given with the same view
name, to build up a more complex collection of OIDs. TYPE is either included
or excluded, which can again define a more complex view (e.g by excluding certain
sensitive objects from an otherwise accessible subtree).
MASK is a list of hex octets (separated by "." or ":")
with the set bits indicating which subidentifiers in the view OID to match against.
This can be used to define a view covering a particular row (or rows) in a table.
If not specified, this defaults to matching the OID exactly (all bits set), thus
defining a simple OID subtree.
access GROUP CONTEXT {any|v1|v2c|usm} LEVEL PREFX READ WRITE NOTIFY
maps from a group of users/communities (with a particular security model
and minimum security level, and in a specific context) to one of three views,
depending on the request being processed.
LEVEL is one of noauth, auth, or priv. PREFX specifies how CONTEXT should be
matched against the context of the incoming request, either exact or prefix.
READ, WRITE and NOTIFY specifies the view to be used for GET*, SET and
TRAP/INFORM requests (althought the NOTIFY view is not currently used). For
v1 or v2c access, LEVEL will need to be noauth.]
As an example, following definitions in the snmpd configuration create a set of definitions for use with SNMP V3
# sample configuration for SNMP V3
# create an SNMP V3 user with an authpassphrase and a privacy passphrase
## username authProto authpassphrase privProto privpassphrase
## -------- --------- -------------- --------- --------------
createUser gandalf MD5 myauthpass DES myprivpass
# Second, map the security name into a group name:
## groupName securityModel securityName
## --------- ------------- ------------
group groupv3 usm gandalf
# Third, create a view for us to let the group have rights to:
## incl/excl subtree mask
## --------- ------- ----
view all included .iso 80
# Fourth, create the access for that group without context
## context sec.model sec.level prefix read write notif
## ------- --------- --------- ------ ---- ----- -----
access groupv3 "" any auth exact all all all
When adding this stuff to your snmp configuration, please remember to restart the agent. Verify this setting using
shell>snmpwalk -v 3 -a MD5 -A myauthpass -x DES \
-X myprivpass -u gandalf -l authpriv localhost interface
IF-MIB::ifNumber.0 = INTEGER: 3
IF-MIB::ifIndex.1 = INTEGER: 1
IF-MIB::ifIndex.2 = INTEGER: 2
IF-MIB::ifIndex.3 = INTEGER: 3
IF-MIB::ifDescr.1 = STRING: lo
IF-MIB::ifDescr.2 = STRING: irda0
IF-MIB::ifDescr.3 = STRING: eth0
IF-MIB::ifType.1 = INTEGER: softwareLoopback(24)
IF-MIB::ifType.2 = INTEGER: other(1)
IF-MIB::ifType.3 = INTEGER: ethernetCsmacd(6)
...
Chapter 8. Viewing Graphs
Graph Trees
A graph tree can be thought of as a hierarchical way of organizing your graphs. Each graph tree consists of zero or more headers or branch nodes that contain leaf nodes such as graphs or trees. Multiple graph trees or branches within a single tree can be combined to form a very powerful way of organizing your graphs.
Creating a Graph Tree
To create a new graph tree, select the Graph Trees menu item under the Management header. Select Add on this page to create a new tree. The following page will prompt you for a tree name, which will be used to identify the graph tree throughout Cacti. Along with the Name, you may select one of four currently supported Sorting Types
Table 8-1. Tree Sporting Type Definitions
Field Description
Name Name of the tree entry. The sort order of all trees themselves is always alphabetical
Sorting Type
Manual Ordering (No Sorting): You may chance the sequence at your will
Alphabetical Ordering: All subtrees are ordered alphabetically, unless specifies otherwise (you may chance sort options at subtree lebel), i.e. 1, Ab, ab
Natural Ordering: ie. ab1, ab2, ab7, ab10, ab20
Numeric Ordering: Leading zeroes are not taken into account when ordering numerically, i.e. 01, 02, 4, 04
Once you type a name, click the Create button to continue. You will be redirected to a page similar to the one below, but without all of the items.
Figure 8-1. Editing a Graph Tree
To start adding items to your tree, click add in the Tree Items box. There are currently three different types of tree items you can choose from: header, graph, or host. Simply choose the type you want, fill in the value for that type, and click Create to make your new graph tree item. Clicking the Add link to the right of any branch will add the new item below that branch, you can change the branch that any item belongs to by changing its Parent Item field.
Please note the "++" and the "--" buttons. They will help you managing large trees. Pressing the "--" will collapse all tree levels while "++" expands all of them. You may expand each single subtree of a collapsed tree to reorder, add or delete entries without much scrolling.
Chapter 9. User Management
Table of Contents
Editing an existing User
Creating a New User
Copying a user
Enable/Disable Users
Batch Copy Users
Delete Users
Guest (Anonymous) Access
In addition to giving you the tools to create sophisticated graphs, Cacti enables you to create users that are tailored specifically to their requirements. Each user has certain settings such as login actions, as well as graph viewing settings. There are also two levels of permissions control, realm permissions and graph permissions which enable you to control what the user can see and change.
Figure 9-1. User Management
Out of the box, there are two users that come with every Cacti installation. The "admin" user, is the main user that by default has access to see and change everything in Cacti. This is the user that you first login with in Cacti, and is probably a good idea to keep around unless you know otherwise. The second user is the "guest" user, which controls which areas/graphs are allowed for unauthenticated users. By default this user only has rights to view, but not change all graphs. This enables any unauthenticated user to visit 'graph_view.php' and view your graphs. This behavior can be changed by either changing the realm permissions for the "guest" user, or disabling the guest user altogether under Cacti Settings. By default in 0.8.7 and later, the "guest" user is not set in the setting, effectively disabling "guest" (Unauthenticated) access to Cacti.
Editing an existing User
To edit an existing user, select the User Management item under the Utilities heading on the Cacti menu. Once at the user management screen, click username of the user you wish to edit. You will see a screen that looks similar to the image below.
Figure 9-2. Editing a User
At minimum, you must specify a User Name and a Password for each user. Each user field is described in more detail below. In addition to these fields, each user can have their own realm permissions", graph permissions, and graph settings. Each of these items are described in this section of the manual.
Table 9-1. Field Description: User Management
Name Description
User Name This field contains the actual login name for the user. There are no character limits this field, but it would make sense to keep it to alphanumeric characters to maintain simplicity.
Full Name (Optional) You can use this field as a more descriptive identifier for the user. It is currently only used for display on the user management page.
Password Enter the password for the user twice, once in each text box. Keep in mind that passwords are case sensitive and the password will remain unchanged if the boxes are both left empty.
Account Options There are currently two account related options that can be set for each user. The first, 'User Must Change Password at Next Login', forces a password change immediately after the user logs in. The second option, 'Allow this User to Keep Custom Graph Settings', dictates whether the user can maintain their own custom graph viewing settings which includes expanding and collapsing trees.
Graph Options There are three permission related options that can be set for each user here. The 'User Has Rights to {Tree,List,Preview} View' checkboxes dictate which graph viewing areas the user can see.
Login Options These options dictate what occurs immediately after the user logs in. The first option, 'Show the page that user pointed their browser to.' will point the user to whatever page they were heading to before being interrupted by the login page. The 'Show the default console screen.' option will always point the user to 'index.php' after a successful login. The last option, 'Show the default graph screen.' will point the user to 'graph_view.php' after a successful login.
Authenication Realm Multiple types of users can exist in Cacti. This setting allows you to specify a user for use with Local, Web Basic or LDAP authenication. Template users must be Local.
Realm Permissions
Realm permissions control which areas of Cacti a user can access. You can edit a user's realm permissions by selecting User Management and choosing the user you want to edit the permissions for. The Realm Permissions box will be displayed in the lower part of the screen. Each "realm" is a grouping that represents common tasks in Cacti, making it easier to fine tune each user's access.
If you want to create a user that can only view graphs, you should select the View Graphs realm and leave everything else unchecked. See the Graph Permissions section for more information about how to fine tune this even more on a per-graph basis. Conversely, if the user needs to access the console, they will need Console Access and any additional realms that you see fit.
Graph Permissions
Graph permissions control which graphs a user is allowed to view, it does not apply to editing graphs. You can edit a user's graph permissions by selecting User Management and choosing the user you want to edit the permissions for. Now select the Graph Permissions tab to view this user's graph permissions. There are three different ways that you can apply graph permissions, by graph, by host, or by graph template. This works by allowing or denying the user to all graphs associated with the particular group. So you can deny a user to a single graph, all graphs associated with a particular host, or all graphs associated with a particular graph template. Combining these three types of assigning graph permissions results in a very powerful graph policy editor.
Each assignment type contains a Default Policy dropdown which can be used to control whether the user should be allowed to view everything or be denied from everything by default in the particular group. It is very important to remember that these policies are evaluated in the order: graph, host, graph template. Therefore, if you set graph's default policy to Deny, but kept host and graph template at Allow, the user's effective policy would be Deny since the graph assignment type is evaluated first. You typically either want to set all default policies to Deny for a restrictive user, or Allow for a non-restrictive user. If you thoroughly understand Cacti's graph permissions system, these default policies can be combined to provide very complex results.
Graph Settings
Cacti stores certain graph viewing settings for each user, which enables each user to view graphs in an optimal way. These preferences controls things such as the preview graph size or the default graph viewing mode to use. In addition to managing these settings here under user management, each user can change their own settings by clicking on the Graphs tab and selecting the Settings tab on the following page. If you want to prevent a user from being able to keep their own graph preferences, uncheck the Allow this User to Keep Custom Graph Settings checkbox in user management. The user will be presented with an "Access Denied" error message if they attempt to click the Settings tab when this box is checked.
Referensi : http://www.cacti.net/downloads/docs/html/basics.html
http://www.cacti.net/downloads/docs/html/index.html
1. Download and install the following pieces of software:
* (optional) Apache and install it to c:\apache or c:\apache2. Make sure to install it as a service.
* Cacti and extract it to the root of your web server directory. Typically c:\inetpub\wwwroot\ or c:\apache2\.
* Cactid and extract it to c:\cactid.
* RRDTool and extract it to c:\rrdtool.
* PHP 4.3.6+ or 5.x and extract it to c:\php.
* MySQL 4.0 or MySQL 4.1. 5.0 is not supported unless you run it in compatibility mode and with the MySQL 5 patch. Install it to c:\mysql.
* (optional) Cygwin. Download setup.exe and keep it around until later used in the document.
* (optional) Net-SNMP and install to c:\net-snmp.
Configure PHP
1.If using PHP 4, move the files in c:\php\dlls to c:\php.
2.Add the following to your Windows PATH environment variable c:\php. The Windows
path can be accessed via the Control Panel at: System | Advanced | Environment Variables | System Variables..
3.Add the following two new environment variables to your system using the procedure above: PHPRC=c:\php.
1. If using PHP 4, create this variable: MIBDIRS=c:\php\mibs
2. If using PHP 5, create this variable: MIBDIRS=c:\php\extras\mibs
4.If using PHP 4.3.5 or less (not recommended), create the following directory c:\tmp.
5.Rename the file c:\php\php.ini.dist to php.ini, and make the following changes to it:
If using PHP 4 uncomment the following lines:
extension_dir = c:\php\extensions
extension=php_snmp.dll
extension=php_sockets.dll
cgi.force_redirect = 0
If using PHP 5 uncomment the following lines:
extension_dir = c:\php\ext
extension=php_mysql.dll
extension=php_snmp.dll
extension=php_sockets.dll
cgi.force_redirect = 0
If using PHP 4.3.5 or less include the following line. If using 4.3.6 or greater, you should remove this line if present.
session.save_path=c:\tmp
6.If you have had previous versions of PHP installed, you had likely moved the PHP system files to in the Windows directory structure. If so, you will have to remove those files. Please review your PHP installation documentation for instructions on removing those files.
7. If you want to allow template importing, uncomment the following line:
file_uploads = On
8. Give the user who will be running the scheduled task, modify rights to:
1. If using PHP 4: c:\php\mibs\.index
2. If using PHP 5: c:\php\extras\mibs\.index
Configure the Webserver (Apache)
1.Make sure you have stopped any IIS web servers before you proceed with Apache installation.
2.If you are using Apache 1.3.x, installation of PHP 5 is not recommended. If using PHP 4, add the following lines to your httpd.conf file in the c:\apache\conf directory:
LoadModule php4_module c:\php\sapi\php4apache.dll
AddModule mod_php4.c
AddType application/x-httpd-php .php
DirectoryIndex index.html index.htm index.php
3.If you are using Apache 2.x, add the following lines to your httpd.conf file in the c:\apache2\conf directory:
If using PHP 4, then add the following lines:
LoadModule php4_module c:\php\sapi\php4apache2.dll
AddType application/x-httpd-php .php
DirectoryIndex index.html index.htm index.php
If using PHP 5, then add the following lines:
LoadModule php5_module c:\php\php5apache2.dll
AddType application/x-httpd-php .php
DirectoryIndex index.html index.htm index.php
Configure the Webserver (IIS)
1.Start the Internet Information Services (IIS) Manager, right click on Default Web Site (in most cases) and select Properties.
2.Under the Home Directory tab, select Configuration and click Add. Browse to the path of php4isapi.dll or php5isapi.dll, and type in .php as the extension.
IIS6: Enable All Verbs and Script Engine.
3.Under the ISAPI Filters tab, click Add and browse to the php4isapi.dll or
php5isapi.dll file. Name the filter "php" and click OK.
4.Under the Documents tab, add index.php to the top of the list.
5. If using IIS6, go to Web Service Extensions and add a new Web Service Extension. Name the extension "php", click Add and browse to the php4isapi.dll or php5isapi.dll file, enable Set Extension status to Enable, and click OK.
6. Under the Default Web Site, right click on Cacti and select Properties.
7. Under the Directory tab, click the Write checkbox..
8. Give the IUSR_XXXX and IIS_WPG users read & execute permissions to the file %windir%\system32\cmd.exe. They will also need read permissions on
9. IIS6: Give the IIS_WPG user modify permissions to the folders /cacti/log and /cacti/rrd.
10.Completely stop and start the IIS service using the following commands:
net stop iisadmin
net start w3svc
Install Cygwin (optional)
1. Installing a single instance of Cygwin, and using it for all applications that require it is recommended so you do not have different versions of the Cygwin dlls laying around on your system, which can cause conflicts.
2. Run setup.exe you previously downloaded.
3. Once you reach the portion of setup entitled Select Packages, install the following:
Base (whole thing)
Libs
libart_lgpl
libfreetype26
libpng12
zlib
Utils
patch
Web
wget
4. Add c:\cygwin\bin to your system path.
5. Move setup.exe to c:\cygwin for future use.
Install RRDTool
1. If you have Cygwin installed, remove the DLL files from the c:\rrdtool directory.
Configure MySQL
1.Start MySQL by running c:\mysql\bin\winmysqladmin.exe.
2.Set a password for the root user
shell> cd mysql\bin
shell> mysqladmin --user=root password somepassword
shell> mysqladmin --user=root --password reload
3.Create the MySQL database:
shell> mysqladmin --user=root --password create cacti
4.Import the default Cacti database:
shell> mysql --user=root --password cacti < c:\apache2\htdocs\cacti\cacti.sql
5.Optional: Create a MySQL username and password for Cacti.
shell> mysql --user=root --password mysql
mysql> GRANT ALL ON cacti.* TO cactiuser@localhost IDENTIFIED BY 'somepassword';
mysql> flush privileges;
6. If you're running MySQL 4.1 then you will need to apply the old password trick for user authentication to work with Cacti.
Stop the MySQL service and add the following to Start Parameter field. Start it again once it has been added.
--old-passwords
You will also need to update the cactiuser account with the old password style:
shell> UPDATE mysql.user SET Password = OLD_PASSWORD('cactipw') WHERE Host = 'localhost' AND User = 'cactiuser';
mysql> FLUSH PRIVILEGES;
7. If you're running MySQL 5, then you will need to run it in compatibility mode by specifying the following in the Start Parameter field for the MySQL service:
--sql-mode=MYSQL40
Install Net-SNMP
1.If you plan to use any hosts with SNMP v2c support, you must download and install the Net-SNMP libraries. Net-SNMP provides installers to install their product. However, caution must be taken not to use long file names as Cacti does not support them in this version. We suggest you install Net-SNMP in a directory such as c:\net-snmp.
Configure Cactid
1.Modify the cactid.conf file in c:\cactid to include the following statements.
DB_Host IP_Address or Hostname (not localhost)
DB_Database cacti
DB_User cactiuser
DB_Password cactipw
All other pre 0.8.6 settings are obsolete. Cactid may not complain if you leave them in, but they are not longer required. Cactid now comes with a binary distribution. Therefore, a basic installation of Cygwin is not longer required, but suggested to help maintain dll version conflicts.
2.If you have Cygwin installed, remove the DLL files and the SH.EXE file from the c:\cactid directory.
Configure Cacti
1.Edit
$database_default = "cacti";
$database_hostname = "localhost";
$database_username = "cactiuser";
$database_password = "cactipw";
2.Point your web browser to:
http://your-server/cacti/
Log in the with a username of admin and password of admin. You will be required to change this password immediately.
Once logged in, you must go to Settings->Paths and verify/update your paths to point to the correct locations. Recommended examples are posted below. If you plan on using Cactid, then it is very important that your all your paths and scripts use forward slashes.
PHP Binary Path:
If using PHP 4, you should change this to:
c:/php/php.exe
If using PHP 5, you should change this to:
c:/php/php.exe
RRDTool Binary Path:
c:/rrdtool/rrdtool.exe
RRDTool Default Font Path:
c:/windows/fonts/arial.ttf
RRDTool Version:
Select the appropriate version
SNMPGET, SNMPWALK Paths:
c:/net-snmp/bin/snmpget.exe
c:/net-snmp/bin/snmpwalk.exe
Cacti Logfile Path:
c:/mycacti/website/cacti/log/cacti.log
Cactid Path:
c:/cactid/cactid.exe
3. Click on Devices. Delete Localhost, since it's set up to use the Linux host template. In the upper right corner, click on Add. Fill in the following information and then click Add.
Description: localhost
Hostname: localhost
Host Template: Windows 2000/XP
4. You should now be looking at the localhost device screen. Right under it's name, there should be some SNMP information listed, if not you should double check the SNMP settings on the server and firewall settings. In the upper right-hand corner, click on Create Graphs for this Host. On the following screen, select a disk partition and network interface. At the bottom of the page, click on Create.
5. Log into the user account you'll be using for the scheduled task and verify starting a Cacti polling cycle works. Do this by running the following from the command prompt:
php c:\
The output should look something like this:
C:\>php c:\inetpub\wwwroot\cacti\poller.php
OK u:0.00 s:0.06 r:1.32
OK u:0.00 s:0.06 r:1.32
OK u:0.00 s:0.16 r:2.59
OK u:0.00 s:0.17 r:2.62
10/28/2005 04:57:12 PM - SYSTEM STATS: Time:4.7272 Method:cmd.php Processes:1 Threads:N/A Hosts:1 HostsPerProcess:2 DataSources:4 RRDsProcessed:2
After this has ran once, you should have cacti.log in /cacti/log/ and rrd files in /cacti/rra/.
6.You are going to need to schedule a task while logged on as an Administrator account, so poller.php can run every 5 minutes. Make sure the Task Scheduler service is started and follow the steps below to begin.
1.Select Start --> Settings --> Control Panel and double click on Scheduled Tasks.
2.Double click on Add Scheduled Task.
3.Click Next and Browse on the following screen. Find c:\php and select php.exe. If using PHP 5 with Cacti 0.8.6f or earlier, use php-win.exe instead. Choose Daily on and click Next.
4.Click Next again without changing the time or date settings.
5.When entering a username and password make sure the user has modify access to the following directories:
c:\
c:\
Make sure the user has read, and execute access to the following directories:
c:\php\
c:\
6.Click Next and Finish to close the wizard.
7.Right click on the task you just created, and select Properties.
8.Select the Schedule tab.
9.Make sure Daily is selected and click the Advanced button.
10.Check the Repeat checkbox, set the repetition for every 5 minutes, set the duration for 24 hours, and check the If the task is still running, stop it at this time checkbox.
11.Click Ok
12.In the Run textbox enter the following text making sure to use the appropriate paths.
c:\php\php.exe c:\
The start in box should say c:\
Apply Patches
1. There are two methods of applying patches to Cacti:
1. If you have Cygwin installed, then the patch instructions which use wget and patch, will work.
2. The other method requires you to visit http://www.cacti.net/downloads/patches/
2. You might need to reapply file/folder security on the files patched. Double check they are correct.
Tweaking
There are several things you can do to speed up your Cacti web server. It's suggested that you only apply these after you have a fully functional Cacti installation.
1. Switch the polling agent in Cacti from cmd.php to Cactid.exe. Go to Settings | Poller | Type.
2. Install the Zend Optimizer for PHP.
3. Set up the query cache in MySQL. Read about how to properly configure the settings. You will need to stop the MySQL service when you edit c:\mysql\my.ini and put in the following:
#The memory allocated to store results from old queries.
query_cache_size=16M
#Don't cache results that are bigger than this.
query_cache_limit=1M
#Query cache type to use.
query_cache_type=1
4. Install FastCGI, which can offer x4 to x8 improvement (for IIS users at least).
5. An extensive list of other optimizations for PHP and MySQL can be found over at phplens.com.
Chapter 4. Upgrading Cacti
1.Backup the old Cacti database.
shell> mysqldump -l --add-drop-table cacti > mysql.cacti
Note: You will probably have to specify the -u and -p flags for the MySQL username and password. This user must have permission to read from Cacti's database or you will end up with an empty backup.
2.Backup the old Cacti directory.
shell> mv cacti cacti_old
3.Extract the distribution tarball.
shell> tar xzvf cacti-version.tar.gz
4.Rename the new Cacti directory to match the old one.
shell> mv cacti-version cacti
5.Edit include/config.php and specify the MySQL user, password and database for your Cacti configuration.
$database_type = "mysql";
$database_default = "cacti";
$database_hostname = "localhost";
$database_username = "cactiuser";
$database_password = "cacti";
6.Copy the *.rrd files from the old Cacti directory.
shell> cp cacti_old/rra/* cacti/rra/
7.Copy any relevant custom scripts from the old Cacti directory. Some script are updated between versions. Therefore, make sure you only over write if the scripts either don't exist or are newer than the distribution's.
shell> cp -u cacti_old/scripts/* cacti/scripts/
8.Copy any relevant custom resource XML files from the old Cacti directory. Some resource XML files are updated between versions. Therefore, make sure you only over write if the XML files either don't exist or are newer than the distribution's.
shell> cp -u -R cacti_old/resource/* cacti/resource/
9.Set the appropriate permissions on Cacti's directories for graph/log generation. You should execute these commands from inside Cacti's directory to change the permissions.
shell> chown -R cactiuser rra/ log/
(Enter a valid username for cactiuser, this user will also be used in the next step for data gathering.)
10.Point your web browser to:
http://your-server/cacti/
Follow the on-screen instructions so your database can be updated to the new version.
II. Basics
Table of Contents
5. Principles of Operation
6. Graph Overview
7. How to Graph Your Network
8. Viewing Graphs
9. User Management
Chapter 5. Principles of Operation
Table of Contents
Data Retrieval
Data Storage
Data Presentation
Cacti operation may be divided into three different tasks:
Figure 5-1. Principles of Operation
Chapter 3. Installing Under Windows
Data Retrieval
First task is to retrieve data. Cacti will do so using its Poller. The Poller is executed from the operating system's scheduler, e.g. crontab for Unix flavored OSes.
In current IT installations, you're dealing with lots of devices of different kind, e.g. servers, network equipment, appliances and the like. To retrieve data from remote targets/hosts, cacti will mainly use the Simple Network Management Protocol SNMP. Thus, all devices capable of using SNMP will be eligible to be monitored by cacti.
Later on, we demonstrate how to extend cacti's capabilities of retrieving data to scripts, script queries and more.
Chapter 6. Graph Overview
Almost everything in Cacti is somehow related to a graph. At any time, you can list all available graphs by clicking on the Graph Management menu item. While it is possible to manually create graphs through this screen, new users should follow the instructions provided in the next chapter for creating new graphs in Cacti.
For users that are familiar with RRDTool , you will immediately recognize that a graph in Cacti is closely modeled after RRDTool's graphs. This makes sense since Cacti provides a user friendly interface to RRDTool without requiring users to understand how RRDTool works. With this in mind, every graph in Cacti has certain settings and at least one graph item associated with it. While graph settings define the overall properties of a graph, the graph items define the data that is to be represented on the graph. So the graph items define which data to display and how it should displayed, and also define what should be displayed on the legend.
Each graph and graph item has a set of parameters which control various aspects of the graph. Fortunately through the use of graph templates, it is not necessary to understand the function of each field to create graphs for your network. When you are ready to take on the task of creating your own graph templates, extensive field descriptions for both graphs and graph items are provided in that section of the manual.
Chapter 7. How to Graph Your Network
Table of Contents
Creating a Device
Creating the Graphs
At this point, you probably realize that graphing is Cacti's greatest strength. Cacti has many powerful features that provide complex graphing and data acquisition, some which have a slight learning curve. Do not let that stop you however, because graphing your network is incredibly simple.
The next two sections will outline the two basic steps which are typically required to create graphs for most devices.
Creating a Device
The first step to creating graphs for your network is adding a device for each network device that you want to create graphs for. A device specifies important details such as the network hostname, SNMP parameters, and host type.
To manage devices within Cacti, click on the Devices menu item. Clicking Add will bring up a new device form. The first two fields, Description and Hostname are the only two fields that require your input beyond the defaults. If your host type is defined under the host template dropdown, be sure to select it here. You can always choose "Generic SNMP-enabled Host" if you are just graphing traffic or "None" if you are unsure. It is important to remember that the host template you choose will not lock you into any particular configuration, it will just provide more intelligent defaults for that type of host.
Figure 7-1. Adding a New Device
The field definitions are as follows
Table 7-1. Device Field Definitions
Field Description
Description This description will show up in the first column of the device list. You may refer to it e.g. in graph titles
Hostname Either an IP address or a hostname. The hostname will be resolved using the standard host resolving mechanisms, e.g. Dynamic Name Services (DNS)
Host Template A Host Template is a container for a list of graph templates that will be related to this host.
Notes New with cacti 0.8.7. Add notes to a host to add arbitrary text.
Disable Host Exclude this host from being polled. This is of particular value, if a device is no longer available, but should be kept e.g. as a reference.
Availability/Reachability Options
Downed Device Detection
NONE: Deactivate downed host detection
PING and SNMP: perform both tests
SNMP: verify SNMP check on OID .1 and .1.3
ICMP: perform a ping test, see below
Ping Method
Available only for "PING and SNMP" or "PING"
ICMP: perform ICMP tests. Requires permissions
UDP: perform a UDP test
TCP: perform a TCP test
Ping Port
Available only for UDP/TCP PING test types.
Please define the port to be tested here. Make sure, that no firewall intercepts the tests
Ping Timeout Value After this time, the test fails. Measured in units of milliseconds
Ping Retry Count The number of times Cacti will attempt to ping a host before failing.
SNMP Options
SNMP Version
Version 1: Use SNMP Version 1. Be aware, that 64bit counters are not supported in this SNMP version
Version 2: Referred to as SNMP V2c in most SNMP documentations
Version 3: SNMP V3, supporting authentication and encryption
SNMP Community SNMP read community for this device.
SNMP Port Enter the UDP port number to use for SNMP (default is 161).
SNMP Timeout The maximum number of milliseconds Cacti will wait for an SNMP response (does not work with php-snmp support).
Maximum OID's Per Get Request
This is a performance feature. Specifies the number of OID's that can be obtained in a single SNMP Get request.
NOTE: This feature only works when using Spine
NOTE: Some devices do not support values > 1
Security Options for SNMP V3
SNMP Username The username of an SNMP V3 createUser statement or equivalent
SNMP Password The authpassphrase of an SNMP V3 createUser statement or equivalent
SNMP Auth Protocol The authentication type of an SNMP V3 createUser statement or equivalent. Select either MD5 or SHA. This entry defaults to MD5.
SNMP Privacy Passphrase The privacy passphrase of an SNMP V3 createUser statement or equivalent.
SNMP Privacy Protocol The privacy protocol of an SNMP V3 createUser statement or equivalent. Select either DES or AES. This entry defaults to DES.
SNMP Context When using the View-Based Access Control Model (VACM), it is possible to specify an SNMP Context when mapping a community name to a security name with a com2sec directive, with the group directive and the access directive. This allows for defining special access models. If using such a parameter with your target's SNMP configuration, specify the context name to be used to access that target here.
After saving your new device, you should be redirected back to the same edit form with some additional information. If you configured SNMP for this host by providing a valid community string, you should see various statistics listed at the top of the page. If you see "SNMP error" instead, this indicates an SNMP problem between Cacti and your device.
Towards the bottom of the page there will be two addition boxes, Associated Data Queries, and Associated Graph Templates. If you selected a host template on the previous page, there will probably be a few items in each box. If there is nothing listed in either box, you will need to associate at least one data query or graph template with your new device or you will not be able to create graphs in the next step. If no available graph template or data query applies to your device, you can check the Cacti templates repository or create your own if nothing currently exists.
A Word About SNMP
The SNMP version that you choose can have a great effect on how SNMP works for you in Cacti. Version 1 should be used for everything unless you have reason to choose otherwise. If you plan on utilizing (and your device supports) high-speed (64-bit) counters, you must select version 2. Starting with Cacti 0.8.7, version 3 is fully implemented.
The way in which Cacti retrieves SNMP information from a host has an effect on which SNMP-related options are supported. Currently there are three types of SNMP retrieval methods in Cacti and are outlined below.
Table 7-2. SNMP Retrieval Types
Type Description Supported Options Places Used
External SNMP Calls the net-snmp snmpwalk and snmpget binaries that are installed on your system. All SNMP options Web interface and PHP poller (poller.php)
Internal SNMP (php-snmp) Uses PHP's SNMP functions which are linked against net-snmp or ucd-snmp at compile time. Version 1 Only (Community and Port) Web interface and PHP poller (poller.php)
Spine SNMP Links directly against net-snmp or ucd-snmp and calls the API directly. All SNMP options C-Based Poller (Spine)
SNMP V3 Options Explained
SNMP supports authentication and encryption features when using SNMP protocol version 3 known as View-Based Access Control Model (VACM). This requires, that the target device in question supports and is configured for SNMP V3 use. In general, configuration of V3 options is target type dependant. The following is cited from man snmpd.conf concerning user definitions
[ SNMPv3 Users
createUser [-e ENGINEID] username (MD5|SHA) authpassphrase [DES|AES] [privpassphrase]
MD5 and SHA are the authentication types to use. DES and AES are the privacy
protocols to use. If the privacy passphrase is not specified, it is assumed
to be the same as the authentication passphrase. Note that the users created will
be useless unless they are also added to the VACM access control tables
described above.
SHA authentication and DES/AES privacy require OpenSSL to be installed and the
agent to be built with OpenSSL support. MD5 authentication may be used without
OpenSSL.
Warning: the minimum pass phrase length is 8 characters.]
VACM directives are explained from man snmpd.conf as follows
[ VACM Configuration
The full flexibility of the VACM is available using four configuration directives -
com2sec, group, view and access. These provide direct configuration of the underlying
VACM tables.
com2sec [-Cn CONTEXT] SECNAME SOURCE COMMUNITY
map an SNMPv1 or SNMPv2c community string to a security name - either from a
particular range of source addresses, or globally ("default"). A restricted
source can either be a specific hostname (or address), or a subnet -
represented as IP/MASK (e.g. 10.10.10.0/255.255.255.0), or IP/BITS
(e.g. 10.10.10.0/24), or the IPv6 equivalents.
The same community string can be specified in several separate directives
(presumably with different source tokens), and the first source/community
combination that matches the incoming request will be selected. Various
source/community combinations can also map to the same security name.
If a CONTEXT is specified (using -Cn), the community string will be mapped
to a security name in the named SNMPv3 context. Otherwise the default
context ("") will be used.
group GROUP {v1|v2c|usm} SECNAME
maps a security name (in the specified security model) into a named group.
Several group directives can specify the same group name, allowing a single
access setting to apply to several users and/or community strings.
Note that groups must be set up for the two community-based models separately -
a single com2sec (or equivalent) directive will typically be accompanied by two
group directives.
view VNAME TYPE OID [MASK]
defines a named "view" - a subset of the overall OID tree. This is most commonly
a single subtree, but several view directives can be given with the same view
name, to build up a more complex collection of OIDs. TYPE is either included
or excluded, which can again define a more complex view (e.g by excluding certain
sensitive objects from an otherwise accessible subtree).
MASK is a list of hex octets (separated by "." or ":")
with the set bits indicating which subidentifiers in the view OID to match against.
This can be used to define a view covering a particular row (or rows) in a table.
If not specified, this defaults to matching the OID exactly (all bits set), thus
defining a simple OID subtree.
access GROUP CONTEXT {any|v1|v2c|usm} LEVEL PREFX READ WRITE NOTIFY
maps from a group of users/communities (with a particular security model
and minimum security level, and in a specific context) to one of three views,
depending on the request being processed.
LEVEL is one of noauth, auth, or priv. PREFX specifies how CONTEXT should be
matched against the context of the incoming request, either exact or prefix.
READ, WRITE and NOTIFY specifies the view to be used for GET*, SET and
TRAP/INFORM requests (althought the NOTIFY view is not currently used). For
v1 or v2c access, LEVEL will need to be noauth.]
As an example, following definitions in the snmpd configuration create a set of definitions for use with SNMP V3
# sample configuration for SNMP V3
# create an SNMP V3 user with an authpassphrase and a privacy passphrase
## username authProto authpassphrase privProto privpassphrase
## -------- --------- -------------- --------- --------------
createUser gandalf MD5 myauthpass DES myprivpass
# Second, map the security name into a group name:
## groupName securityModel securityName
## --------- ------------- ------------
group groupv3 usm gandalf
# Third, create a view for us to let the group have rights to:
## incl/excl subtree mask
## --------- ------- ----
view all included .iso 80
# Fourth, create the access for that group without context
## context sec.model sec.level prefix read write notif
## ------- --------- --------- ------ ---- ----- -----
access groupv3 "" any auth exact all all all
When adding this stuff to your snmp configuration, please remember to restart the agent. Verify this setting using
shell>snmpwalk -v 3 -a MD5 -A myauthpass -x DES \
-X myprivpass -u gandalf -l authpriv localhost interface
IF-MIB::ifNumber.0 = INTEGER: 3
IF-MIB::ifIndex.1 = INTEGER: 1
IF-MIB::ifIndex.2 = INTEGER: 2
IF-MIB::ifIndex.3 = INTEGER: 3
IF-MIB::ifDescr.1 = STRING: lo
IF-MIB::ifDescr.2 = STRING: irda0
IF-MIB::ifDescr.3 = STRING: eth0
IF-MIB::ifType.1 = INTEGER: softwareLoopback(24)
IF-MIB::ifType.2 = INTEGER: other(1)
IF-MIB::ifType.3 = INTEGER: ethernetCsmacd(6)
...
Chapter 8. Viewing Graphs
Graph Trees
A graph tree can be thought of as a hierarchical way of organizing your graphs. Each graph tree consists of zero or more headers or branch nodes that contain leaf nodes such as graphs or trees. Multiple graph trees or branches within a single tree can be combined to form a very powerful way of organizing your graphs.
Creating a Graph Tree
To create a new graph tree, select the Graph Trees menu item under the Management header. Select Add on this page to create a new tree. The following page will prompt you for a tree name, which will be used to identify the graph tree throughout Cacti. Along with the Name, you may select one of four currently supported Sorting Types
Table 8-1. Tree Sporting Type Definitions
Field Description
Name Name of the tree entry. The sort order of all trees themselves is always alphabetical
Sorting Type
Manual Ordering (No Sorting): You may chance the sequence at your will
Alphabetical Ordering: All subtrees are ordered alphabetically, unless specifies otherwise (you may chance sort options at subtree lebel), i.e. 1, Ab, ab
Natural Ordering: ie. ab1, ab2, ab7, ab10, ab20
Numeric Ordering: Leading zeroes are not taken into account when ordering numerically, i.e. 01, 02, 4, 04
Once you type a name, click the Create button to continue. You will be redirected to a page similar to the one below, but without all of the items.
Figure 8-1. Editing a Graph Tree
To start adding items to your tree, click add in the Tree Items box. There are currently three different types of tree items you can choose from: header, graph, or host. Simply choose the type you want, fill in the value for that type, and click Create to make your new graph tree item. Clicking the Add link to the right of any branch will add the new item below that branch, you can change the branch that any item belongs to by changing its Parent Item field.
Please note the "++" and the "--" buttons. They will help you managing large trees. Pressing the "--" will collapse all tree levels while "++" expands all of them. You may expand each single subtree of a collapsed tree to reorder, add or delete entries without much scrolling.
Chapter 9. User Management
Table of Contents
Editing an existing User
Creating a New User
Copying a user
Enable/Disable Users
Batch Copy Users
Delete Users
Guest (Anonymous) Access
In addition to giving you the tools to create sophisticated graphs, Cacti enables you to create users that are tailored specifically to their requirements. Each user has certain settings such as login actions, as well as graph viewing settings. There are also two levels of permissions control, realm permissions and graph permissions which enable you to control what the user can see and change.
Figure 9-1. User Management
Out of the box, there are two users that come with every Cacti installation. The "admin" user, is the main user that by default has access to see and change everything in Cacti. This is the user that you first login with in Cacti, and is probably a good idea to keep around unless you know otherwise. The second user is the "guest" user, which controls which areas/graphs are allowed for unauthenticated users. By default this user only has rights to view, but not change all graphs. This enables any unauthenticated user to visit 'graph_view.php' and view your graphs. This behavior can be changed by either changing the realm permissions for the "guest" user, or disabling the guest user altogether under Cacti Settings. By default in 0.8.7 and later, the "guest" user is not set in the setting, effectively disabling "guest" (Unauthenticated) access to Cacti.
Editing an existing User
To edit an existing user, select the User Management item under the Utilities heading on the Cacti menu. Once at the user management screen, click username of the user you wish to edit. You will see a screen that looks similar to the image below.
Figure 9-2. Editing a User
At minimum, you must specify a User Name and a Password for each user. Each user field is described in more detail below. In addition to these fields, each user can have their own realm permissions", graph permissions, and graph settings. Each of these items are described in this section of the manual.
Table 9-1. Field Description: User Management
Name Description
User Name This field contains the actual login name for the user. There are no character limits this field, but it would make sense to keep it to alphanumeric characters to maintain simplicity.
Full Name (Optional) You can use this field as a more descriptive identifier for the user. It is currently only used for display on the user management page.
Password Enter the password for the user twice, once in each text box. Keep in mind that passwords are case sensitive and the password will remain unchanged if the boxes are both left empty.
Account Options There are currently two account related options that can be set for each user. The first, 'User Must Change Password at Next Login', forces a password change immediately after the user logs in. The second option, 'Allow this User to Keep Custom Graph Settings', dictates whether the user can maintain their own custom graph viewing settings which includes expanding and collapsing trees.
Graph Options There are three permission related options that can be set for each user here. The 'User Has Rights to {Tree,List,Preview} View' checkboxes dictate which graph viewing areas the user can see.
Login Options These options dictate what occurs immediately after the user logs in. The first option, 'Show the page that user pointed their browser to.' will point the user to whatever page they were heading to before being interrupted by the login page. The 'Show the default console screen.' option will always point the user to 'index.php' after a successful login. The last option, 'Show the default graph screen.' will point the user to 'graph_view.php' after a successful login.
Authenication Realm Multiple types of users can exist in Cacti. This setting allows you to specify a user for use with Local, Web Basic or LDAP authenication. Template users must be Local.
Realm Permissions
Realm permissions control which areas of Cacti a user can access. You can edit a user's realm permissions by selecting User Management and choosing the user you want to edit the permissions for. The Realm Permissions box will be displayed in the lower part of the screen. Each "realm" is a grouping that represents common tasks in Cacti, making it easier to fine tune each user's access.
If you want to create a user that can only view graphs, you should select the View Graphs realm and leave everything else unchecked. See the Graph Permissions section for more information about how to fine tune this even more on a per-graph basis. Conversely, if the user needs to access the console, they will need Console Access and any additional realms that you see fit.
Graph Permissions
Graph permissions control which graphs a user is allowed to view, it does not apply to editing graphs. You can edit a user's graph permissions by selecting User Management and choosing the user you want to edit the permissions for. Now select the Graph Permissions tab to view this user's graph permissions. There are three different ways that you can apply graph permissions, by graph, by host, or by graph template. This works by allowing or denying the user to all graphs associated with the particular group. So you can deny a user to a single graph, all graphs associated with a particular host, or all graphs associated with a particular graph template. Combining these three types of assigning graph permissions results in a very powerful graph policy editor.
Each assignment type contains a Default Policy dropdown which can be used to control whether the user should be allowed to view everything or be denied from everything by default in the particular group. It is very important to remember that these policies are evaluated in the order: graph, host, graph template. Therefore, if you set graph's default policy to Deny, but kept host and graph template at Allow, the user's effective policy would be Deny since the graph assignment type is evaluated first. You typically either want to set all default policies to Deny for a restrictive user, or Allow for a non-restrictive user. If you thoroughly understand Cacti's graph permissions system, these default policies can be combined to provide very complex results.
Graph Settings
Cacti stores certain graph viewing settings for each user, which enables each user to view graphs in an optimal way. These preferences controls things such as the preview graph size or the default graph viewing mode to use. In addition to managing these settings here under user management, each user can change their own settings by clicking on the Graphs tab and selecting the Settings tab on the following page. If you want to prevent a user from being able to keep their own graph preferences, uncheck the Allow this User to Keep Custom Graph Settings checkbox in user management. The user will be presented with an "Access Denied" error message if they attempt to click the Settings tab when this box is checked.
Referensi : http://www.cacti.net/downloads/docs/html/basics.html
http://www.cacti.net/downloads/docs/html/index.html
Selasa, 09 Februari 2010
DSS 1
Memahami konsep pengembangan sistem.
Pelajari PADI, fase-fase SDLC.
Jelaskan prototyping.
Memahami faktor-faktor yang menyebabkan keberhasilan atau kegagalan DSS.
Pelajari pentingnya manajemen proyek.
Jelaskan tiga tingkat teknologi DSS.
Memahami proses belajar terlibat dalam pengembangan DSS.
Sylvania Osram Berpikir Kecil, Big-Mengembangkan Strategizes yang Infonet Sistem Portal HR Vignette
Menciptakan sebuah portal bisnis khusus untuk memecahkan masalah tertentu
Prototipe
Interaktif, Web-based
HR Portal
Pikirkan kecil, strategi besar
Fokus pada masalah-masalah kunci pertama
Rencana untuk mencapai keberhasilan kecil cepat
Intranet berbasis portal untuk mempekerjakan, lowongan pekerjaan, tunjangan, bonus, pensiun informasi
Systems Development Life Cycle
Empat fase
Perencanaan
Analisis
Desain
Pelaksanaan
Siklis
Dapat kembali ke fase-fase lain
Waterfall Model
Bab 6 Decision Support System Development
Tools/Peralatan
Komputer-dibantu alat desain perangkat lunak
Upper Case --
Sistem menciptakan diagram
Lower Case
Mengatur diagram dan kode
KASUS Terpadu
Kombinasi
Desain RAD tools
Kelas perusahaan repositori dan kolaborasi
UML modeling
Analisis dan software desain
Kode debug metode
Pengujian dan jaminan kualitas alat
Successful Project Management
Dilaksanakan sebagai dasar
Menentukan lingkup proyek
Mengelola perubahan dan scope creep
Dapatkan dukungan dari manajemen tingkat atas
Menetapkan waktu, saat penting, dan anggaran yang didasarkan pada tujuan realistis
Libatkan pengguna
Dokumen segalanya
Pelaksanaan Kegagalan
Implementation Failures
Kurangnya keterlibatan stakeholder
Persyaratan lengkap
Scope creep
Harapan yang tidak realistis
Juara Proyek daun
Kurangnya keterampilan atau keahlian
Memadai sumber daya manusia
Teknologi baru
Evolusioner pengganggu
Evolutionary Disruptors
Lingkungan pengembangan
Faktor budaya organisasi
Hilangnya dukungan manajemen puncak
User dan analis sikap
Pengalaman pengguna
Tim pengembangan kemampuan
Proses pembangunan
Pengguna pendidikan, dukungan, keterlibatan, pelatihan
Project Management Tools
Perangkat lunak manajemen proyek dapat memungkinkan:
Kolaborasi antara tim-tim yang berbeda
Sumber daya dan pengelolaan program
Manajemen portofolio
Web diaktifkan
Agregat dan analisis data proyek
Pelajari PADI, fase-fase SDLC.
Jelaskan prototyping.
Memahami faktor-faktor yang menyebabkan keberhasilan atau kegagalan DSS.
Pelajari pentingnya manajemen proyek.
Jelaskan tiga tingkat teknologi DSS.
Memahami proses belajar terlibat dalam pengembangan DSS.
Sylvania Osram Berpikir Kecil, Big-Mengembangkan Strategizes yang Infonet Sistem Portal HR Vignette
Menciptakan sebuah portal bisnis khusus untuk memecahkan masalah tertentu
Prototipe
Interaktif, Web-based
HR Portal
Pikirkan kecil, strategi besar
Fokus pada masalah-masalah kunci pertama
Rencana untuk mencapai keberhasilan kecil cepat
Intranet berbasis portal untuk mempekerjakan, lowongan pekerjaan, tunjangan, bonus, pensiun informasi
Systems Development Life Cycle
Empat fase
Perencanaan
Analisis
Desain
Pelaksanaan
Siklis
Dapat kembali ke fase-fase lain
Waterfall Model
Bab 6 Decision Support System Development
Tools/Peralatan
Komputer-dibantu alat desain perangkat lunak
Upper Case --
Sistem menciptakan diagram
Lower Case
Mengatur diagram dan kode
KASUS Terpadu
Kombinasi
Desain RAD tools
Kelas perusahaan repositori dan kolaborasi
UML modeling
Analisis dan software desain
Kode debug metode
Pengujian dan jaminan kualitas alat
Successful Project Management
Dilaksanakan sebagai dasar
Menentukan lingkup proyek
Mengelola perubahan dan scope creep
Dapatkan dukungan dari manajemen tingkat atas
Menetapkan waktu, saat penting, dan anggaran yang didasarkan pada tujuan realistis
Libatkan pengguna
Dokumen segalanya
Pelaksanaan Kegagalan
Implementation Failures
Kurangnya keterlibatan stakeholder
Persyaratan lengkap
Scope creep
Harapan yang tidak realistis
Juara Proyek daun
Kurangnya keterampilan atau keahlian
Memadai sumber daya manusia
Teknologi baru
Evolusioner pengganggu
Evolutionary Disruptors
Lingkungan pengembangan
Faktor budaya organisasi
Hilangnya dukungan manajemen puncak
User dan analis sikap
Pengalaman pengguna
Tim pengembangan kemampuan
Proses pembangunan
Pengguna pendidikan, dukungan, keterlibatan, pelatihan
Project Management Tools
Perangkat lunak manajemen proyek dapat memungkinkan:
Kolaborasi antara tim-tim yang berbeda
Sumber daya dan pengelolaan program
Manajemen portofolio
Web diaktifkan
Agregat dan analisis data proyek
Senin, 08 Februari 2010
DSS
Objectives
Tentukan analisis sistem dan menghubungkannya dengan definisi ruang lingkup, analisis masalah, analisis persyaratan, desain logis, dan fase analisis keputusan.
Menggambarkan sejumlah pendekatan analisis sistem untuk memecahkan masalah sistem bisnis.
Jelaskan definisi lingkup, analisis masalah, analisis persyaratan, desain logis, dan fase analisis keputusan dalam hal blok bangunan sistem informasi.
Jelaskan definisi lingkup, analisis masalah, analisis persyaratan, desain logis, dan fase analisis keputusan dalam hal tujuan, peserta, input, output, teknik, dan langkah-langkah.
Mengidentifikasi bab dalam buku ini yang dapat membantu Anda mempelajari alat analisis sistem spesifik dan teknik.
Apa itu Sistem Analisis?
Analisis sistem â € "pemecahan masalah teknik yang terurai suatu sistem menjadi komponen-komponen potongan untuk tujuan mempelajari seberapa baik bagian-bagian komponen tersebut bekerja dan berinteraksi untuk mencapai tujuan mereka.
Desain sistem â € "sebagai pelengkap teknik pemecahan masalah (untuk analisis sistem) yang reassembles sebuah SYSTEMA € ™ s potongan-potongan komponen kembali ke SYSTEMA lengkap €" mudah-mudahan, sistem yang diperbaiki. Ini mungkin melibatkan penambahan, menghapus, dan mengubah potongan relatif terhadap sistem yang asli.
Analisis sistem informasi â € "tahapan perkembangan mereka dalam proyek pengembangan sistem informasi yang terutama berfokus pada masalah dan persyaratan bisnis, terpisah dari teknologi apapun yang dapat atau akan digunakan untuk mengimplementasikan sebuah solusi untuk masalah tersebut....
Context of Systems Analysis
Repository
Repositori â € "lokasi (atau set lokasi) di mana analis sistem, perancang sistem dan pembangun sistem yang menyimpan semua dokumentasi yang berhubungan dengan satu atau lebih sistem atau proyek.
Direktori jaringan komputer yang dihasilkan proyek file yang berisi surat-menyurat, laporan, dan data
Alat KASUS kamus atau bebas (Bab 3)
Cetak dokumentasi (binder dan sistem perpustakaan)
Intranet website interface untuk komponen di atas
Model-Driven Analysis Methods
nalisis model-driven â € "sebuah Pendekatan pemecahan masalah yang menekankan sistem model gambar bergambar untuk memvalidasi dan mendokumentasikan baik yang ada dan / atau sistem yang diusulkan. Pada akhirnya, model sistem yang menjadi cetak biru untuk merancang dan membangun sistem yang ditingkatkan.
Model â € "representasi dari realitas baik atau visi. Sejak â € OEA Bernilai gambar seribu kata, â € Sebagian besar model Menggunakan gambar untuk mewakili kenyataan atau visi
Model-Driven Approaches
Pendekatan Tradisional
Analisis Terstruktur
Berfokus pada aliran data melalui proses
Kunci model: data flow diagram
Informasi Teknik
Berfokus pada struktur data yang disimpan
Kunci model: diagram hubungan entitas
Pendekatan Berorientasi Objek
mengintegrasikan data dan proses kekhawatiran menjadi objek
Obyek - yang enkapsulasi data (disebut properti) yang menggambarkan orang yang diskrit, objek, tempat, peristiwa, atau benda, dengan semua proses (disebut metode) yang diperbolehkan menggunakan atau memperbarui data dan properti. Satu-satunya cara untuk mengakses atau memperbarui data objek adalah dengan menggunakan proses standar objek.
Unified Modeling Language (UML)
A Simple Process Model
A Simple Data Model
A Simple Object Model
Accelerated Systems Analysis
Pendekatan analisis sistem dipercepat menekankan pembangunan prototipe untuk lebih cepat mengidentifikasi pengguna bisnis dan persyaratan untuk sebuah sistem baru.
prototipe â € "skala kecil, tidak lengkap, tetapi bekerja sampel dari sistem yang dikehendaki.
Pendekatan analisis sistem Dipercepat
Discovery Prototyping
Architected Rapid Analisis
Discovery Prototyping
Discovery prototyping â € "teknik yang digunakan untuk mengidentifikasi usersâ € ™ kebutuhan bisnis dengan memiliki mereka bereaksi cepat-dan-kotor pelaksanaan kebutuhan tersebut.
Keuntungan
Prototipe melayani œIâ € â € ™ ll tahu apa yang saya inginkan ketika saya melihat ita € cara berpikir yang menjadi ciri dari banyak pengguna dan manajer.
Kekurangan
Dapat menjadi sibuk dengan akhir € â € œlook dan feelâ prematur
Dapat mendorong fokus pada dini, dan komitmen untuk, desain
Pengguna dapat disesatkan untuk percaya bahwa sistem yang lengkap dapat dibangun dengan cepat dengan menggunakan alat prototipe
Rapid Architected Analysis
Analisis architected cepat â € "sebuah pendekatan yang mencoba untuk menurunkan model sistem (seperti yang dijelaskan sebelumnya dalam bagian ini) dari sistem yang sudah ada atau penemuan prototipe.
Reverse engineering â € "penggunaan teknologi yang membaca kode program untuk database yang sudah ada, program aplikasi, dan / atau user interface dan secara otomatis menghasilkan sistem yang setara model.
Requirements Discovery
Persyaratan penemuan - proses, yang digunakan oleh analis sistem untuk mengidentifikasi atau sistem mengeluarkan masalah dan kebutuhan solusi dari komunitas pengguna.
Requirements Discovery Methods
Fact-finding - proses mengumpulkan informasi tentang masalah sistem, peluang, solusi persyaratan, dan prioritas.
Sampling yang ada dokumentasi, laporan, form, database, dll
Penelitian literatur yang relevan
Pengamatan terhadap sistem yang sekarang
Kuesioner dan survei
Wawancara
Joint persyaratan perencanaan (JRP)-penggunaan difasilitasi lokakarya untuk menyatukan semua sistem pemilik, pengguna, dan analis, dan beberapa perancang dan pembangun sistem untuk bersama-sama melakukan analisis sistem.
Dianggap sebagai bagian dari metode yang lebih besar yang disebut pengembangan aplikasi bersama (JAD), yang lebih komprehensif JRP penerapan teknik untuk seluruh proses pengembangan sistem.
Business Process Redesign
Merancang ulang proses bisnis (BPR) - aplikasi dari metode analisis sistem untuk tujuan secara dramatis mengubah dan memperbaiki proses bisnis dasar dari sebuah organisasi, teknologi informasi independen.
Agile Methods
Metode agile â € "integrasi dari berbagai pendekatan analisis sistem dan desain untuk aplikasi yang dianggap tepat untuk persoalan yang dipecahkan dan sistem yang dikembangkan.
Metodologi komersial tidak memaksakan pendekatan tunggal (analisis terstruktur, IE, öÔÄ) pada sistem analis.
Sebaliknya, mereka mengintegrasikan semua pendekatan populer menjadi koleksi metode tangkas.
Pengembang sistem diberikan fleksibilitas untuk memilih dari berbagai alat dan teknik untuk menyelesaikan tugas-tugas yang terbaik di tangan,
Metodologi FAST hipotetis beroperasi dengan cara ini.
FAST Systems Analysis Phases
Scope Definition Phase
Apakah proyek senilai lihat?
Tahap Analisis Masalah
Adalah sebuah sistem baru layak bangunan?
Fase Analisis Persyaratan
Apa yang pengguna butuhkan dan inginkan dari sistem baru?
Logical Design Phase
Apa yang harus sistem baru lakukan?
Fase Analisis Keputusan
Apa solusi terbaik?
Context of Scope Definition Phase
Tugas untuk Fase Definisi Lingkup
Tasks for the Scope Definition Phase
Kunci Persyaratan untuk Fase Definisi Lingkup
Key Terms for Scope Definition Phase
Steering body - komite bisnis eksekutif dan manajer sistem yang mempelajari dan memprioritaskan proposal proyek bersaing untuk menentukan proyek-proyek yang akan kembali yang paling nilai bagi organisasi dan dengan demikian harus disetujui untuk pengembangan sistem berlanjut.
Juga disebut komite pengarah.
Project charter - penyampaian akhir untuk fase pemeriksaan pendahuluan. Sebuah proyek piagam mendefinisikan lingkup proyek, rencana, metodologi, standar, dan seterusnya.
Rencana awal pendahuluan mencakup jadwal dan sumber daya tugas (juga disebut rencana awal).
Rencana rinci dan jadwal untuk menyelesaikan tahap berikutnya dari proyek.
Sample Request for System Services
Contoh Permintaan Layanan Sistem
Contoh Soal Pernyataan
Sample Problem Statements
Context of Problem Analysis Phase
Konteks Analisis Soal Fase
Tugas Analisis Soal Fase
Tasks of the Problem Analysis Phase
Persyaratan kunci dari Fase Analisis Soal
Key Terms of the Problem Analysis Phase
Sebab-dan-analisis efek - teknik di mana masalah-masalah yang dipelajari untuk menentukan sebab dan akibat.
Dalam prakteknya, gejala efek dapat lebih berakar masalah yang, pada gilirannya, harus dianalisis sebab dan akibat sampai sebab dan akibat tidak menghasilkan gejala-gejala dari masalah lain.
Context Diagram - sebuah model bergambar yang menunjukkan bagaimana sistem berinteraksi dengan dunia di sekitarnya dan menetapkan secara umum sistem input dan output.
Contoh Penyebab-dan-Effect Analysis
Sample Cause-and-Effect Analysis
Contoh Context Diagram
Sample Context Diagram
Persyaratan kunci dari Fase Analisis Soal (lanjutan)
Key Terms of the Problem Analysis Phase (cont.)
Tujuan â € "sebuah ukuran keberhasilan. Ini adalah sesuatu yang Anda harapkan untuk dicapai, jika diberikan sumber daya yang memadai.
Mengurangi jumlah tidak tertagihnya rekening pelanggan sebesar 50 persen dalam tahun depan.
Meningkat sebesar 25 persen jumlah aplikasi pinjaman yang dapat diproses selama delapan jam shift.
Penurunan sebesar 50 persen waktu yang dibutuhkan untuk menjadwal ulang banyak produksi ketika workstation malfungsi.
Kendala â € "sesuatu yang akan membatasi fleksibilitas dalam mendefinisikan solusi untuk tujuan Anda. Pada dasarnya, kendala tidak dapat diubah.
Sistem yang baru harus beroperasi 15 April.
Sistem baru tidak dapat biaya lebih dari $ 350.000.
Sistem baru harus berbasis web.
Sistem baru harus tagihan pelanggan setiap 15 hari.
Laporan Perbaikan Sistem Outline
System Improvement Report Outline
Ringkasan eksekutif (sekitar 2 halaman)
Ringkasan rekomendasi
Ringkasan masalah, kesempatan, dan arahan
Pernyataan singkat mengenai tujuan perbaikan sistem
Penjelasan singkat tentang isi laporan
Informasi latar belakang (sekitar 2 halaman)
Daftar wawancara dan memfasilitasi pertemuan kelompok yang dilakukan
Daftar sumber-sumber informasi lain yang dieksploitasi
Deskripsi teknik analisis yang digunakan
Ikhtisar sistem yang sekarang (sekitar 5 halaman)
Implikasi strategis (jika proyek merupakan bagian dari atau dampak yang ada rencana strategis IS)
Model dari sistem yang sekarang
Interface model (showing lingkup proyek)
Model data (showing lingkup proyek)
Model geografis (showing lingkup proyek)
Model Proses (menunjukkan dekomposisi fungsional saja)
Analisis sistem yang sekarang (sekitar 5-10 halaman)
Masalah kinerja, peluang, analisis sebab-akibat
Masalah informasi, peluang, analisis sebab-akibat
Masalah ekonomi, peluang, analisis sebab-akibat
Control masalah, peluang, analisis sebab-akibat
Masalah efisiensi, peluang, analisis sebab-akibat
Masalah layanan, kesempatan, dan analisis sebab-akibat
Rekomendasi (sekitar 5-10 halaman)
Perbaikan sistem tujuan dan prioritas
Kendala
Rencana Proyek
Lingkup penilaian ulang dan perbaikan
Revisi master plan
Rencana rinci untuk fase definisi
Lampiran
Setiap rinci model sistem
Dokumen lain sebagaimana mestinya
Requirements Analysis Phase Tasks
Fase Analisis Persyaratan Tugas
Persyaratan kunci Fase Analisis Persyaratan
Key Terms of Requirements Analysis Phase
Fungsional â € "deskripsi kegiatan dan pelayanan sistem harus memberikan.
input, output, proses, data yang disimpan
Persyaratan nonfungsional â € "deskripsi fitur lainnya, karakteristik, dan kendala yang mendefinisikan sistem yang memuaskan.
Kinerja, kemudahan belajar dan menggunakan, anggaran, tenggat waktu, dokumentasi, keamanan, kontrol audit internal
Proposal Sistem khas Outline
Pendahuluan
Tujuan dari laporan
Latar belakang proyek yang mengarah ke laporan ini
Cakupan laporan
Struktur laporan
Alat dan teknik yang digunakan
Solusi yang dihasilkan
Analisis kelayakan (biaya-manfaat)
Persyaratan sistem informasi
Alternatif solusi dan analisis kelayakan
Rekomendasi
Lampiran
LAPORAN PERANCANGAN SISTEM PENUNJANG KEPUTUSAN
LAPORAN PERANCANGAN SISTEM PENUNJANG KEPUTUSAN
DAFTAR ISI
1. PENDAHULUAN
a. LATAR BELAKANG
Berisi latar belakang mengapa perusahaan membutuhkan DSS.
b. PERMASALAHAN
Berikan beberapa contoh permasalahan yg membutuhkan bantuan DSS.
c. TUJUAN DAN MANFAAT
Uraikan tujuan dan manfaat pengembangan DSS pada perusahaan.
d. RUANG LINGKUP
Sebutkan ruang lingkup pengerjaan DSS. Sebutkan juga unit/divisi/bagian yang dipilih sebagai studi kasus.
e. TAHAPAN PENGERJAAN
Uraikan tahapan dalam perancangan DSS.
2. PROFIL PERUSAHAAN
a. SEJARAH SINGKAT
Uraikan sedikit mengenai visi, misi,serta tujuan perusahaan. Sejarah singkat berdirinya perusahaan dan sebagainya. Uraikan secara singkat saja, tidak perlu banyak-banyak!
b. STRUKTUR ORGANISASI
Masukkan organization chart.
3. ANALISA SISTEM
a. ANALISA PERMASALAHAN (PROBLEM ANALYSIS)
Analisa proses bisnis pada suatu unit/divisi/bagian yang dipilih. Uraikan permasalahan yang ada pada proses bisnis tersebut. Jabarkan solusi yang direkomendasikan untuk memperbaiki/meningkatkan kemampuan proses pengambilan keputusan.
b. ANALISA KEBUTUHAN (REQUIREMENTS ANALYSIS)
Uraikan seluruh kebutuhan untuk memperbaiki/meningkatkan kemampuan proses pengambilan keputusan.
c. RANCANGAN LOGICAL (LOGICAL DESIGN)
Buat rancangan logical: pemodelan data (ER-Diagram) & proses (DFD)
4. PROTOTIPE
a. SKENARIO PENGAMBILAN KEPUTUSAN
Uraikan skenario kegiatan yang berkaitan dengan pengambilan keputusan oleh unit yang dipilih
b. LANGKAH-LANGKAH DALAM PENGAMBILAN KEPUTUSAN
Uraikan langkah-langkah dalam pengambilan keputusan. Sertai dengan screen shot aplikasi DSS!
***
DAFTAR ISI
1. PENDAHULUAN
a. LATAR BELAKANG
Berisi latar belakang mengapa perusahaan membutuhkan DSS.
b. PERMASALAHAN
Berikan beberapa contoh permasalahan yg membutuhkan bantuan DSS.
c. TUJUAN DAN MANFAAT
Uraikan tujuan dan manfaat pengembangan DSS pada perusahaan.
d. RUANG LINGKUP
Sebutkan ruang lingkup pengerjaan DSS. Sebutkan juga unit/divisi/bagian yang dipilih sebagai studi kasus.
e. TAHAPAN PENGERJAAN
Uraikan tahapan dalam perancangan DSS.
2. PROFIL PERUSAHAAN
a. SEJARAH SINGKAT
Uraikan sedikit mengenai visi, misi,serta tujuan perusahaan. Sejarah singkat berdirinya perusahaan dan sebagainya. Uraikan secara singkat saja, tidak perlu banyak-banyak!
b. STRUKTUR ORGANISASI
Masukkan organization chart.
3. ANALISA SISTEM
a. ANALISA PERMASALAHAN (PROBLEM ANALYSIS)
Analisa proses bisnis pada suatu unit/divisi/bagian yang dipilih. Uraikan permasalahan yang ada pada proses bisnis tersebut. Jabarkan solusi yang direkomendasikan untuk memperbaiki/meningkatkan kemampuan proses pengambilan keputusan.
b. ANALISA KEBUTUHAN (REQUIREMENTS ANALYSIS)
Uraikan seluruh kebutuhan untuk memperbaiki/meningkatkan kemampuan proses pengambilan keputusan.
c. RANCANGAN LOGICAL (LOGICAL DESIGN)
Buat rancangan logical: pemodelan data (ER-Diagram) & proses (DFD)
4. PROTOTIPE
a. SKENARIO PENGAMBILAN KEPUTUSAN
Uraikan skenario kegiatan yang berkaitan dengan pengambilan keputusan oleh unit yang dipilih
b. LANGKAH-LANGKAH DALAM PENGAMBILAN KEPUTUSAN
Uraikan langkah-langkah dalam pengambilan keputusan. Sertai dengan screen shot aplikasi DSS!
***
JARINGAN KOMPUTER
KOMPONEN-KOMPONEN JARINGAN KOMPUTER
Untuk dapat menghubungkan komputer dalam sebuah jaringan, ada beberapa komponen yang biasa digunakan diantaranya:
1. Kartu Penghubung Jaringan (Network Interface Card=NIC)
2. Repeater
3. HUB
4. Switch
5. Bridge
6. Router
Network Interface Card (NIC)
Kartu antarmuka jaringan (Network Interface Card) yang disingkat NIC merupakan peralatan utama dari jaringan yang harus ada pada setiap komputer untuk dapat berkomunikasi. Ada beberapa macam Network Interface Card yang bisa digunakan pada komputer IBM dan kompatibelnya, diantaranya yang sering digunakan adalah:
Ethernet
Archnet
Token Ring
Dari ketiga macam tersebut yang paling banyak digunakan adalah Ethernet.
Network Interface Card (NIC)
Ethernet Card :
Dikembangkan oleh Xerox Corp. pada tahun 1970-an, kemudian menjadi sangat populer tahun 1980-an karena diterima sebagai standar IEEE 802.3
Cara kerja Ethernet adalah berdasarkan broadcast network, yaitu setiap node menerima setiap transmisi data yang dikirim oleh sebuah node.
FUNGSI NETWORK INTERFACE CARD=NIC :
Mempersiapkan data dari komputer agar dapat dilewatkan ke media penghubung.
Mengirim data ke komputer lain.
Mengontrol aliran data antarkomputer dan sistem perkabelan.
Ethernet menggunakan metode CSMA/CD (Carrier Sense Multiple Access/Collision Detection) baseband.
Metode CSMA/CD dapat dijelaskan sebagai berikut :
Sebelum mengirimkan paket data, setiap node melihat apakah setiap network juga sedang mengirim paket data.
Jika network sedang busy, node tersebut menunggu sampai tidak ada lagi paket data yang dikirimkan oleh node.
Jika suatu saat network sepi, barulah node tersebut mengirimkan paket datanya.
Jika pada saat yang bersamaan ada dua node yang mengirimkan paket datanya, maka terjadi tabrakan/collision.
Dideteksi oleh ethernet card dengan cara mengukur tegangan kabel, jika tegangan kabel melewati batas tertentu, maka telah terjadi collision)
Jika collision terjadi, maka masing-masing ethernet card berhenti memancarkan dan kemudian menunggu dengan selang waktu yang random/acak untuk mencoba mengirimkan paket data kembali.
Karena selang waktu pengiriman paket data yang acak ini, maka kemungkinan collision lebih lanjut menjadi semakin kecil.
Oleh sebab itu umumnya jaringan Ethernet dipakai hanya untuk transmisi half-duplex, yaitu pada suatu saat hanya dapat mengirim atau menerima saja.
Karena dalam satu jaringan terdapat banyak ethernet card, maka harus ada metode untuk membedakan masing-masing ethernet card tersebut.
Oleh karena itu pada setiap ethernet card tertera kode khusus sepanjang 48 bit, yang dikenal sebagai ethernet address.
Besar bandwith maksimum yang dapat dikelola oleh ethernet adalah 10 dan 100 Mbps.
Untuk jaringan ethernet ber-bandwith 10 Mbps, digunakan kabel UTP kategori 3, atau kabel coaxial RG 58,
Sedangkan untuk bandwith 100 Mbps, digunakan kabel UTP kategori 5.
Repeater
Fungsi utama repeater adalah untuk memperkuat sinyal dengan cara menerima sinyal dari suatu segmen kabel LAN lalu memancarkannya kembali dengan kekuatan yang sama dengan sinyal asli pada segmen kabel LAN yang lain.
Dengan cara ini jarak kabel antara dua komputer dapat diperjauh.
HUB
Bentuk fisik Hub adalah seperti sebuah kotak yang memiliki banyak konektor RJ45 female.
Setiap konektor pada hub dapat dipasang kabel UTP yang telah di beri konektor RJ45 male pada ujungnya.
Hub sebenarnya adalah sebuah “multiport repeaters’ yang menghubungkan kabel UTP yang disusun dengan topologi star.
Seperti pada repeater, hub hanya bekerja pada level tegangan listrik, yaitu memperkuat sinyal listrik yang masuk, lalu mengeluarkannya dengan kuat tegangan listrik seperti awal.
Hub sama sekali tidak melakukan “traffic control” sehingga jika terlalu banyak port pada hub yang dipakai (misalnya 32 port), maka kinerja jaringan akan turun disebabkan seringnya terjadi collision antar-ethernet card.
Antara 1 hub dengan lainnya dapat di hubungkan melalui kabel coaxial atau UTP yang di crosslink,
Biasanya ada 1 buah port yang dilengkapi switch untuk menjadikannya sebagai port crosslink, sehingga dapat menggunakan kabel UTP biasa untuk menghubungkan 1 hub dengan hub lainnya.
Hub hanya memiliki satu domain collision, maka semua peralatan yang berhubungan dengan suatu hub menggunakan satu domain collision secara bersamaan walaupun peralatan dihubungkan ke port-port yang berlainan dari hub.
Switch
Seperti bridge, switch juga bekerja di lapisan data link
Memiliki keunggulan setiap port di dalam switch memiliki domain collision sendiri-sendiri.
Switch sering disebut juga multi-port bridge.
Switch mempunyai tabel penterjemah pusat yang memiliki daftar penerjemah untuk semua port.
Switch menciptakan Virtual Private Network (VPN) dari port pengirim dan port penerima sehingga jika dua host sedang berkomunikasi lewat VPN tersebut, mereka tidak mengganggu segment lainnya.
Jika satu port sedang sibuk, port-port lain tetap dapat berfungsi.
Penggunaan switch semakin populer terutama dengan harganya yang semakin terjangkau.
Switch memungkinkan transmisi full-duplex untuk hubungan port ke port
Pengiriman dan penerimaan dapat dilakukan bersamaan dengan menggunakan VPN
Persyaratan untuk dapat mengadakan hubungan full-duplex adalah hanya satu komputer atau server saja yang dapat dihubungkan ke satu port dari switch (satu segmen per node).
Komputer harus memiliki network card yang mampu mengadakan hubungan full-duplex,
Collision detection dan loopback harus disable
Switch
Bridge
Bridge digunakan untuk memisahkan jaringan yang luas menjadi sub-jaringan yang lebih kecil dan bekerja di lapisan data link.
Beberapa bridge mempelajari alamat ethernet setiap device yang terhubung dengannya dan mengatur alur frame berdasarkan alamat tersebut.
Bridge dapat digunakan untuk menghubungkan jaringan yang menggunakan metode transmisi berbeda dan/atau medium akses kontrol yang berbeda, misalnya bridge dapat menghubungkan ethernet baseband dengan ethernet boardband, dan sebagainya.
Mekanisme yang digunakan oleh bridge disebut mekanisme frame filtering, yaitu frame yang diterima disimpan sementara di bridge dan kemudian di forward ke workstation pada LAN lainnya.
Bridge
Router
Router memiliki kemampuan untuk melewatkan paket IP dari satu jaringan ke jaringan lain yang mungkin memiliki banyak jalur diantara keduanya.
Router-router yang terhubung di Internet memiliki algoritma routing terdistribusi yang digunakan untuk memilih jalur terbaik yang dilalui paket IP dari satu jaringan ke jaringan lain.
Router umumnya digunakan untuk menghubungkan sejumlah LAN, sekaligus mengisolasikan trafik data antara LAN satu dengan lainnya.
Jika dua atau lebih LAN terhubung dengan satu router, maka setiap LAN akan dianggap memiliki subnetwork yang berbeda.
Router dapat digolongkan menjadi dua jenis, yaitu
1. Router dedicated (router buatan pabrik, misalnya Cisco http://www.cisco.com, 3Com http://www.3com.com )
2. PC Router. Sebuah PC dapat dikatakan sebagai PC Router jika PC tersebut memiliki lebih dari satu network interface dan PC tersebut memiliki kemampuan mem-forward paket IP.
Router
MEDIA PENGHUBUNG DAN INTERFACE JARINGAN
Media yang biasa digunakan dalam jaringan komputer terdiri dari teknologi kabel dan wireless.
Kabel merupakan media penghubung yang paling banyak digunakan pada LAN. Ada beberapa macam kabel yang digunakan pada jaringan, diantaranya adalah:
a. Kabel Twisted Pair (belitan ganda). Ada dua jenis kabel yaitu:
- Unshielded Twisted Pair = Kabel belitan ganda tak berpelindung
- Shielded Twisted Pair = Kabel belitan ganda berpelindung.
b. Kabel Coaxial
c. Kabel Fiber Optic (serat optic)
Kabel Unshielded Twisted Pair (UTP)
Karakteristik dari kabel unshielded twisted pair (UTP) adalah sebagai berikut:
Kabel twisted pair adalah kabel-kabel yang disusun berpasangan dan di twist satu sama lain.
Untuk kabel jenis UTP, terdiri atas empat pasang (delapan buah kabel).
Kabel UTP kategori 3, dapat melewatkan data dengan bandwith sampai 10 Mbps.
Kabel UTP kategori 5, dapat melewatkan data dengan bandwith s.d 100 Mbps.
Kabel UTP kategori 5e dan 6, dapat melewatkan data dengan bandwith s.d Gbps.
Hanya dapat melewatkan satu channel data (baseband), karena itu dibutuhkan konsentrator untuk menghubungkan satu node dengan node yang lain.
Konsentrator yang digunakan biasanya berupa HUB atau SWITCH.
Panjang kabel maksimum (ideal) adalah 100 meter.
Kabel Unshielded Twisted Pair (UTP)
Kabel Unshielded Twisted Pair (UTP)
Standar Warna Kabel UTP adalah Putih Orange/Orange, Putih Hijau/Hijau, Putih Biru/Biru dan Putih Coklat/Coklat.
Untuk menghubungkan kabel ke PC atau ke Hub menggunakan jack/konektor RJ 45.
Prosedur pemasangan kabel UTP untuk menghubungkan perangkat- perangkat jaringan ada 2 cara:
1. Straight
2. Cross
Agar kabel UTP kategori 5 dapat mengalirkan data dengan bandwith 100 Mbps maka kabel UTP tersebut harus dipasang pada konektor RJ45 dengan urutan warna sebagai berikut:
Kabel Straight
Kabel Cross
Kegunaan Kabel Straight
kegunaan Kabel cross
Media Tanpa Kabel (Wireless)
Penghubung media jaringan ini dapat menggunakan transmisi :
Gelombang radio
Microwave, atau
Infrared.
Jaringan tanpa kabel saat ini semakin banyak digunakan karena peningkatan jumlah WAN, dan kebutuhan komputer berjalan (mobile computing).
Gelombang Radio
Teknologi radio mengirim data melalui frekuensi radio dan secara praktis tidak terdapat batasan jarak.
Teknologi ini digunakan untuk menghubungkan LAN melewati jarak geografik yang sangat jauh.
Transmisi Radio biasanya mahal, dan harus mengikuti peraturan/regulasi pemerintah, dan sangat rentan terhadap interference elektronik dan atmosfir.
Teknologi ini sangat mudah didengar, sehingga membutuhkan encrypsi atau modifikasi transmisi lainnya untuk mendapatkan level keamanan yang dapat diterima.
Media Tanpa Kabel (Wireless)
Gelombang Radio
gambar 34
Microwaves
Transmisi data Microwave menggunakan frekuensi tinggi untuk jarak dekat dan transmisi global;
Keterbatasan utama adalah antara pengirim (transmitter) dan penerima (receiver) harus dapat saling terlihat atau disebut juga dengan line of sight (LOS).
Transmisi Microwave biasanya digunakan untuk menghubungkan LAN dalam gedung terpisah, dimana penggunaan media fisik sangat tidak memungkinkan atau tidak praktis.
Teknologi wireless yang banyak dipakai menggunakan standar IEEE 802.11B untuk indoor (dalam ruangan) dan IEEE 802.16 untuk outdoor (luar ruangan), yaitu dengan menggunakan frekuensi pembawa 2,4 GHz dan kecepatan pemindahan data sampai 11 Mbps.
Sebuah indoor unit dengan antena luar, bisa mencapai maksimum sekitar 5 Km sedangkan sebuah outdoor unit dengan antena luar, bisa mencapai sampai 40 Km.
Untuk dapat menghubungkan komputer dalam sebuah jaringan, ada beberapa komponen yang biasa digunakan diantaranya:
1. Kartu Penghubung Jaringan (Network Interface Card=NIC)
2. Repeater
3. HUB
4. Switch
5. Bridge
6. Router
Network Interface Card (NIC)
Kartu antarmuka jaringan (Network Interface Card) yang disingkat NIC merupakan peralatan utama dari jaringan yang harus ada pada setiap komputer untuk dapat berkomunikasi. Ada beberapa macam Network Interface Card yang bisa digunakan pada komputer IBM dan kompatibelnya, diantaranya yang sering digunakan adalah:
Ethernet
Archnet
Token Ring
Dari ketiga macam tersebut yang paling banyak digunakan adalah Ethernet.
Network Interface Card (NIC)
Ethernet Card :
Dikembangkan oleh Xerox Corp. pada tahun 1970-an, kemudian menjadi sangat populer tahun 1980-an karena diterima sebagai standar IEEE 802.3
Cara kerja Ethernet adalah berdasarkan broadcast network, yaitu setiap node menerima setiap transmisi data yang dikirim oleh sebuah node.
FUNGSI NETWORK INTERFACE CARD=NIC :
Mempersiapkan data dari komputer agar dapat dilewatkan ke media penghubung.
Mengirim data ke komputer lain.
Mengontrol aliran data antarkomputer dan sistem perkabelan.
Ethernet menggunakan metode CSMA/CD (Carrier Sense Multiple Access/Collision Detection) baseband.
Metode CSMA/CD dapat dijelaskan sebagai berikut :
Sebelum mengirimkan paket data, setiap node melihat apakah setiap network juga sedang mengirim paket data.
Jika network sedang busy, node tersebut menunggu sampai tidak ada lagi paket data yang dikirimkan oleh node.
Jika suatu saat network sepi, barulah node tersebut mengirimkan paket datanya.
Jika pada saat yang bersamaan ada dua node yang mengirimkan paket datanya, maka terjadi tabrakan/collision.
Dideteksi oleh ethernet card dengan cara mengukur tegangan kabel, jika tegangan kabel melewati batas tertentu, maka telah terjadi collision)
Jika collision terjadi, maka masing-masing ethernet card berhenti memancarkan dan kemudian menunggu dengan selang waktu yang random/acak untuk mencoba mengirimkan paket data kembali.
Karena selang waktu pengiriman paket data yang acak ini, maka kemungkinan collision lebih lanjut menjadi semakin kecil.
Oleh sebab itu umumnya jaringan Ethernet dipakai hanya untuk transmisi half-duplex, yaitu pada suatu saat hanya dapat mengirim atau menerima saja.
Karena dalam satu jaringan terdapat banyak ethernet card, maka harus ada metode untuk membedakan masing-masing ethernet card tersebut.
Oleh karena itu pada setiap ethernet card tertera kode khusus sepanjang 48 bit, yang dikenal sebagai ethernet address.
Besar bandwith maksimum yang dapat dikelola oleh ethernet adalah 10 dan 100 Mbps.
Untuk jaringan ethernet ber-bandwith 10 Mbps, digunakan kabel UTP kategori 3, atau kabel coaxial RG 58,
Sedangkan untuk bandwith 100 Mbps, digunakan kabel UTP kategori 5.
Repeater
Fungsi utama repeater adalah untuk memperkuat sinyal dengan cara menerima sinyal dari suatu segmen kabel LAN lalu memancarkannya kembali dengan kekuatan yang sama dengan sinyal asli pada segmen kabel LAN yang lain.
Dengan cara ini jarak kabel antara dua komputer dapat diperjauh.
HUB
Bentuk fisik Hub adalah seperti sebuah kotak yang memiliki banyak konektor RJ45 female.
Setiap konektor pada hub dapat dipasang kabel UTP yang telah di beri konektor RJ45 male pada ujungnya.
Hub sebenarnya adalah sebuah “multiport repeaters’ yang menghubungkan kabel UTP yang disusun dengan topologi star.
Seperti pada repeater, hub hanya bekerja pada level tegangan listrik, yaitu memperkuat sinyal listrik yang masuk, lalu mengeluarkannya dengan kuat tegangan listrik seperti awal.
Hub sama sekali tidak melakukan “traffic control” sehingga jika terlalu banyak port pada hub yang dipakai (misalnya 32 port), maka kinerja jaringan akan turun disebabkan seringnya terjadi collision antar-ethernet card.
Antara 1 hub dengan lainnya dapat di hubungkan melalui kabel coaxial atau UTP yang di crosslink,
Biasanya ada 1 buah port yang dilengkapi switch untuk menjadikannya sebagai port crosslink, sehingga dapat menggunakan kabel UTP biasa untuk menghubungkan 1 hub dengan hub lainnya.
Hub hanya memiliki satu domain collision, maka semua peralatan yang berhubungan dengan suatu hub menggunakan satu domain collision secara bersamaan walaupun peralatan dihubungkan ke port-port yang berlainan dari hub.
Switch
Seperti bridge, switch juga bekerja di lapisan data link
Memiliki keunggulan setiap port di dalam switch memiliki domain collision sendiri-sendiri.
Switch sering disebut juga multi-port bridge.
Switch mempunyai tabel penterjemah pusat yang memiliki daftar penerjemah untuk semua port.
Switch menciptakan Virtual Private Network (VPN) dari port pengirim dan port penerima sehingga jika dua host sedang berkomunikasi lewat VPN tersebut, mereka tidak mengganggu segment lainnya.
Jika satu port sedang sibuk, port-port lain tetap dapat berfungsi.
Penggunaan switch semakin populer terutama dengan harganya yang semakin terjangkau.
Switch memungkinkan transmisi full-duplex untuk hubungan port ke port
Pengiriman dan penerimaan dapat dilakukan bersamaan dengan menggunakan VPN
Persyaratan untuk dapat mengadakan hubungan full-duplex adalah hanya satu komputer atau server saja yang dapat dihubungkan ke satu port dari switch (satu segmen per node).
Komputer harus memiliki network card yang mampu mengadakan hubungan full-duplex,
Collision detection dan loopback harus disable
Switch
Bridge
Bridge digunakan untuk memisahkan jaringan yang luas menjadi sub-jaringan yang lebih kecil dan bekerja di lapisan data link.
Beberapa bridge mempelajari alamat ethernet setiap device yang terhubung dengannya dan mengatur alur frame berdasarkan alamat tersebut.
Bridge dapat digunakan untuk menghubungkan jaringan yang menggunakan metode transmisi berbeda dan/atau medium akses kontrol yang berbeda, misalnya bridge dapat menghubungkan ethernet baseband dengan ethernet boardband, dan sebagainya.
Mekanisme yang digunakan oleh bridge disebut mekanisme frame filtering, yaitu frame yang diterima disimpan sementara di bridge dan kemudian di forward ke workstation pada LAN lainnya.
Bridge
Router
Router memiliki kemampuan untuk melewatkan paket IP dari satu jaringan ke jaringan lain yang mungkin memiliki banyak jalur diantara keduanya.
Router-router yang terhubung di Internet memiliki algoritma routing terdistribusi yang digunakan untuk memilih jalur terbaik yang dilalui paket IP dari satu jaringan ke jaringan lain.
Router umumnya digunakan untuk menghubungkan sejumlah LAN, sekaligus mengisolasikan trafik data antara LAN satu dengan lainnya.
Jika dua atau lebih LAN terhubung dengan satu router, maka setiap LAN akan dianggap memiliki subnetwork yang berbeda.
Router dapat digolongkan menjadi dua jenis, yaitu
1. Router dedicated (router buatan pabrik, misalnya Cisco http://www.cisco.com, 3Com http://www.3com.com )
2. PC Router. Sebuah PC dapat dikatakan sebagai PC Router jika PC tersebut memiliki lebih dari satu network interface dan PC tersebut memiliki kemampuan mem-forward paket IP.
Router
MEDIA PENGHUBUNG DAN INTERFACE JARINGAN
Media yang biasa digunakan dalam jaringan komputer terdiri dari teknologi kabel dan wireless.
Kabel merupakan media penghubung yang paling banyak digunakan pada LAN. Ada beberapa macam kabel yang digunakan pada jaringan, diantaranya adalah:
a. Kabel Twisted Pair (belitan ganda). Ada dua jenis kabel yaitu:
- Unshielded Twisted Pair = Kabel belitan ganda tak berpelindung
- Shielded Twisted Pair = Kabel belitan ganda berpelindung.
b. Kabel Coaxial
c. Kabel Fiber Optic (serat optic)
Kabel Unshielded Twisted Pair (UTP)
Karakteristik dari kabel unshielded twisted pair (UTP) adalah sebagai berikut:
Kabel twisted pair adalah kabel-kabel yang disusun berpasangan dan di twist satu sama lain.
Untuk kabel jenis UTP, terdiri atas empat pasang (delapan buah kabel).
Kabel UTP kategori 3, dapat melewatkan data dengan bandwith sampai 10 Mbps.
Kabel UTP kategori 5, dapat melewatkan data dengan bandwith s.d 100 Mbps.
Kabel UTP kategori 5e dan 6, dapat melewatkan data dengan bandwith s.d Gbps.
Hanya dapat melewatkan satu channel data (baseband), karena itu dibutuhkan konsentrator untuk menghubungkan satu node dengan node yang lain.
Konsentrator yang digunakan biasanya berupa HUB atau SWITCH.
Panjang kabel maksimum (ideal) adalah 100 meter.
Kabel Unshielded Twisted Pair (UTP)
Kabel Unshielded Twisted Pair (UTP)
Standar Warna Kabel UTP adalah Putih Orange/Orange, Putih Hijau/Hijau, Putih Biru/Biru dan Putih Coklat/Coklat.
Untuk menghubungkan kabel ke PC atau ke Hub menggunakan jack/konektor RJ 45.
Prosedur pemasangan kabel UTP untuk menghubungkan perangkat- perangkat jaringan ada 2 cara:
1. Straight
2. Cross
Agar kabel UTP kategori 5 dapat mengalirkan data dengan bandwith 100 Mbps maka kabel UTP tersebut harus dipasang pada konektor RJ45 dengan urutan warna sebagai berikut:
Kabel Straight
Kabel Cross
Kegunaan Kabel Straight
kegunaan Kabel cross
Media Tanpa Kabel (Wireless)
Penghubung media jaringan ini dapat menggunakan transmisi :
Gelombang radio
Microwave, atau
Infrared.
Jaringan tanpa kabel saat ini semakin banyak digunakan karena peningkatan jumlah WAN, dan kebutuhan komputer berjalan (mobile computing).
Gelombang Radio
Teknologi radio mengirim data melalui frekuensi radio dan secara praktis tidak terdapat batasan jarak.
Teknologi ini digunakan untuk menghubungkan LAN melewati jarak geografik yang sangat jauh.
Transmisi Radio biasanya mahal, dan harus mengikuti peraturan/regulasi pemerintah, dan sangat rentan terhadap interference elektronik dan atmosfir.
Teknologi ini sangat mudah didengar, sehingga membutuhkan encrypsi atau modifikasi transmisi lainnya untuk mendapatkan level keamanan yang dapat diterima.
Media Tanpa Kabel (Wireless)
Gelombang Radio
gambar 34
Microwaves
Transmisi data Microwave menggunakan frekuensi tinggi untuk jarak dekat dan transmisi global;
Keterbatasan utama adalah antara pengirim (transmitter) dan penerima (receiver) harus dapat saling terlihat atau disebut juga dengan line of sight (LOS).
Transmisi Microwave biasanya digunakan untuk menghubungkan LAN dalam gedung terpisah, dimana penggunaan media fisik sangat tidak memungkinkan atau tidak praktis.
Teknologi wireless yang banyak dipakai menggunakan standar IEEE 802.11B untuk indoor (dalam ruangan) dan IEEE 802.16 untuk outdoor (luar ruangan), yaitu dengan menggunakan frekuensi pembawa 2,4 GHz dan kecepatan pemindahan data sampai 11 Mbps.
Sebuah indoor unit dengan antena luar, bisa mencapai maksimum sekitar 5 Km sedangkan sebuah outdoor unit dengan antena luar, bisa mencapai sampai 40 Km.
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