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IPM uses the Round Trip Time Monitor (RTTMON) Management Information Base (MIB) provided in Cisco IOS Release 11.2. There are two versions of the MIB available: one for SNMP v1, and one for SNMP v2. This appendix provides a brief overview of MIBs and instructions for obtaining Cisco MIBs.
From the perspective of a network manager, network management takes place between two major types of systems: those in control, called managing systems, and those observed and controlled, called managed systems. The most common managing system is called a network management system (NMS). Managed systems can include hosts, servers, or network components such as routers or intelligent repeaters.
To promote interoperability, cooperating systems must adhere to a common framework and a common language, called a protocol. In the Internet Network Management Framework, that protocol is the Simple Network Management Protocol (SNMP).
The exchange of information between managed network devices and a robust NMS is essential for reliable performance of a managed network. Because some devices have a limited ability to run management software, most of the computer processing burden is assumed by the NMS. The NMS runs the network management applications, such as CiscoWorks or Internetwork Performance Monitor, that present management information to network managers and other users.
In a managed device, specialized low-impact software modules, called agents, access information about the device and make it available to the NMS. Managed devices maintain values for a number of variables and report those, as required, to the NMS. For example, an agent might report such data as the number of bytes and packets in and out of the device, or the number of broadcast messages sent and received. In the Internet Network Management Framework, each of these variables is referred to as a managed object. A managed object is anything that can be managed, anything that an agent can access and report back to the NMS. All managed objects are contained in the MIB, a database of the managed objects.
An NMS can control a managed device by sending a message to an agent of that managed device requiring the device to change the value of one or more of its variables. The managed devices can respond to commands such as set or get. The set command is used by the NMS to control the device. The get command is used by the NMS to monitor the device.
If your NMS is unable to get requested information from a managed device such as a Cisco router, the MIB that allows that specific data collection might be missing. Typically, if an NMS cannot retrieve a particular MIB variable, either the NMS does not recognize the MIB variable or the agent does not support the MIB variable. If the NMS does not recognize a specified MIB variable, you might need to load the MIB into the NMS, usually by means of a MIB compiler. For example, you might need to load the Cisco MIB or the supported RFC MIB into the NMS to execute a specified data collection. If the agent does not support a specified MIB variable, you must find out what release of Cisco IOS or system software you are running. Different MIBs are supported in different software releases.
For more information about MIBs, specifically Cisco MIBs, refer to the Cisco IOS Release 11.2 Cisco Management Information Base (MIB) User Quick Reference.
You can obtain the files that describe the MIBs supported by Cisco products using anonymous FTP or the World Wide Web (WWW) to access Cisco Connection Online (CCO), formerly Cisco Information Online.
To access the MIBs via FTP, perform the following steps:
Step 1 Issue the ftp ftp.cisco.com command.
Step 2 Log in with the username anonymous and enter your e-mail address when prompted for the password.
Step 3 Issue the cd pub/mibs command to go to the directory that contains the MIB files.
Step 4 Issue the get README command to obtain the README file containing a description of the Cisco Systems public MIB area.
To determine the MIBs supported for each Cisco product, go to the supportlists subdirectory where you will find directories for all Cisco products. Refer to the supportlist.txt file in each directory, as necessary, to determine the MIBs supported on that platform, for each Cisco IOS software release, and the location of the desired MIB file. Cisco IOS MIB files are in the v1 and v2 subdirectories. You can then use the ftp command get mib-filename to retrieve the MIB file.
A description of issues you might encounter when loading Cisco MIBs into your NMS is located at ftp://www.cisco.com/pub/mibs/app_notes/mib-compliers.
To access the MIBs on CCO via the WWW, use one of these URLs: http://www.cisco.com/public/mibs or ftp://www.cisco.com/pub/mibs.
The RTTMON MIB includes three traps that were created by Cisco:
You must load these traps into your NMS. Cisco provides scripts that you can use to load the traps onto the following:
If you are using an NMS other than those listed above, refer to the documentation that came with your NMS for information on how to load traps.
Obtain the script available from the Cisco web site at this URL:
http://cio.cisco.com/public/mibs/contrib/traps.script
Read the instructions at the top of the file.
Obtain the script available from the Cisco web site at this URL:
http://www.cisco.com/public/mibs/traps/hpov/trapd.conf
Read the instructions at the top of the file.
Obtain the file named CISCO-RTTMON-MIB.traps from the Cisco web site at this URL:
http://www.cisco.com/public/mibs/traps/
Add the contents of this file to the snmp.trap file, normally found in the /var/adm/snmp directory.
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