Obtaining MIBs

You might be wondering where you can find MIBs. The suggested starting point for Cisco MIBs is http://www.cisco.com/go/mibs. It offers a set a powerful tools, such as the MIB Locator, SNMP Object Navigator, MIBs for Cisco IOS and non-IOS products, and various technical tips about MIBs in general and how to load them onto the NMS.

If you are looking for IETF RFCs, you can check http://www.rfc-editor.org/ or http://www.faqs.org/rfcs/; these are IETF archives. If instead you want to find "work-in-progress documents" (drafts), a good search engine is the Draft Tracker, at https://datatracker.ietf.org/. You can find new tools at http://tools.ietf.org/.

Here are some simple examples. Note that the tool also allows queries that are more complex.

Find out which devices support the EXPRESSION-MIB:

1.	Go to http://www.cisco.com/go/mibs and start the MIB Locator.
2.	Select the EXPRESSION-MIB from the list of MIBs. Result: 75304 entries found.
3.	Narrow the search by IOS release, platform family, or feature set. By selecting IOS 12.1(3), you reduce the number of results to 197. Next, you can select the desired platform or feature set or just browse through the results. If you select the IP PLUS image, 13 results remain.

Translate the OID into an object name or the object name into an OID to receive object details:

1.	Go to http://www.cisco.com/go/mibs and start the SNMP Object Navigator.
2.	Enter the MIB object name, such as ifHCInMulticastPkts. Click Translate, which displays the following results: Object: ifHCInMulticastPkts OID: 1.3.6.1.2.1.31.1.1.1.8 Type: Counter64 Permission: read-only Status: current MIB: IF-MIB
3.	Click View Supporting Images, which results in a long list of all supported IOS images.

Display all MIBs that are supported by a particular IOS release:

1.	Go to http://www.cisco.com/go/mibs and start the MIB Locator.
2.	Select the following: IOS release: 12.2(16) Device: 3660 Image: IP PLUS You see the following results: Image information: c3660-is-mz.12.2-16 MIBs supported in this image: A list of 132 MIBs is displayed.

Identify the MIB dependencies for the EXPRESSION-MIB, list the compilation sequence, and download the MIB(s):

1.	Go to http://www.cisco.com/go/mibs and start the SNMP Object Navigator.
2.	Click MIB Support in Software.
3.	Click View and Download MIBs. You can choose a MIB or browse through the list. You can view the MIB content or MIB dependencies and download the MIB. This step provides useful help. The result for the EXPRESSION-MIB is the following MIB sequence: - SNMPv2-SMI - SNMPv2-TC - SNMPv2-CONF - SNMPv2-MIB - CISCO-SMI - IANAifType-MIB - RFC1155-SMI - RFC-1212 - RFC1213-MIB - IF-MIB - CISCO-TC - SNMPv2-SMI-v1 - SNMPv2-TC-v1 - EXPRESSION-MIB

In addition to a specific MIB file, another relevant file is CAPABILITY. It describes the implementation details—specifically, per platform. Capability statements are used when describing functionality of agents with respect to object and event notification definitions. RFC 2580 defines the AGENT-CAPABILITIES construct, which is used to concisely convey such capabilities. Here is an example:

Identify the MIB capabilities of the CISCO-PING-MIB:

1.	Go to http://www.cisco.com/go/mibs and start the SNMP Object Navigator.
2.	Click MIB Support in Software.
3.	Click View and Download MIBs.
4.	Choose the CISCO-PING-MIB: In the section More Downloads you see Capability File: CISCO-PING-CAPABILITY. This links to the capability file, CISCO-PING-CAPABILITY. Alternatively, you can download the file from ftp://ftp.cisco.com/pub/mibs/v2/CISCO-PING-CAPABILITY.my.

Afterwards, you can extract the details:

ciscoPingCapabilityV10R02 AGENT-CAPABILITIES
    PRODUCT-RELEASE     "Cisco IOS 10.2"
    STATUS              current
    DESCRIPTION         "Cisco Ping MIB capabilities."
    SUPPORTS            CISCO-PING-MIB
        INCLUDES        { ciscoPingMIBGroup }
    ::= { ciscoPingCapability 1 }

The preceding seven lines explain that ciscoPingMIBGroup has been supported since IOS release 10.2.

The file contains more details:

ciscoPingCapabilityCatOSV08R0301 AGENT-CAPABILITIES
    PRODUCT-RELEASE     "Cisco CatOS 8.3(1)."
    STATUS              current
    DESCRIPTION         "CISCO-PING-MIB capabilities."
    SUPPORTS            CISCO-PING-MIB
        INCLUDES        { ciscoPingMIBGroupVpn }
        VARIATION       ciscoPingVrfName
            ACCESS      not-implemented
            DESCRIPTION
                        "Information not available on CatOS."

These ten lines explain that ciscoPingMIBGroupVpn has been supported since Cisco CatOS 8.3 (1); however, ciscoPingVrfName is not implemented.

If you are interested in a specific MIB, but you do not like reading MIBs in plain text, http://www.mibdepot.com/ graphically represents the MIB context. After searching for the MIB, you can display a summary view, a tree view, and a detailed view.