Circuit Interface Identification Persistence for SNMP

The Circuit Interface Identification Persistence for SNMP feature maintains the user-defined name of the circuit (defined in the cciDescr object) across reboots, and allows the advanced users of Simple Network Management Protocol (SNMP) to consistently identify the circuits.

Finding Feature Information

Your software release may not support all the features documented in this module. For the latest caveats and feature information, see Bug Search Tool and the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the feature information table.

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Information about Circuit Interface Identification Persistence for SNMP

Circuit Interface Identification Persistence

The Circuit Interface MIB (CISCO-CIRCUIT-INTERFACE-MIB) provides a MIB object (cciDescr) that can be used to identify individual circuit-based interfaces for SNMP monitoring. The Circuit Interface Identification Persistence for SNMP feature maintains this user-defined name of the circuit across reboots, allowing the consistent identification of circuit interfaces. Circuit Interface Identification Persistence is enabled using the snmp mib persist circuit global configuration command.

The Circuit Interface Identification Persistence for SNMP feature was introduced with the CSCds67851. The Circuit Interface MIB (CISCO-CIRCUIT-INTERFACE-MIB) provides a MIB object (cciDescr) that can be used to identify individual circuit-based interfaces for SNMP monitoring. The Cisco Circuit Interface Identification MIB was introduced in CSCdp81924.

The Circuit Interface Identification Persistence for SNMP feature maintains the user-defined name of the circuit (defined in the cciDescr object) across reboots, allowing for the consistent identification of circuits.

The Circuit Interface Identification Persistence for SNMP feature is a supplement to the Interface Index Persistence feature. Circuit Interface Identification Persistence is enabled using the snmp mib persist circuit global configuration command. Use this command if you need to consistently identify circuits using SNMP across reboots. This command is disabled by default because this feature uses NVRAM.

In addition, the show snmp mib ifmib ifindex EXEC mode command allows you to display the Interfaces MIB ifIndex values directly on your system without an NMS; the show snmp mib EXEC mode command allows you to display a list of MIB module identifiers registered directly on your system with an NMS. The snmp ifmib ifalias long command allows you to specify a description for interfaces or subinterfaces of up to 256 characters in length. Prior to the introduction of this command, ifAlias descriptions for SNMP management were limited to 64 characters.

How to Configure Circuit Interface Identification Persistence for SNMP

Configuring Interface Index Display and Interface Indexes and Long Name Support

The display of Interface Indexes lets advanced users of SNMP view information about the interface registrations directly on a managed agent. An external NMS is not required.

Configuration of Long Alias Names for the interfaces lets users configure the ifAlias (the object defined in the MIB whose length is restricted to 64) up to 255 bytes.

Before You Begin

SNMP must be enabled on your system.

The Interface Index Display and Interface Alias Long Name Support feature is not supported on all Cisco platforms. Use Cisco Feature Navigator to find information about platform support and software image support.

Perform this task to configure the IF-MIB to retain ifAlias values of longer than 64 characters and to configure the ifAlias values for an interface.


Note
To verify if the ifAlias description is longer than 64 characters, perform an SNMP MIB walk for the ifMIB ifAlias variable from an NMS and verify that the entire description is displayed in the values for ifXEntry.18.

The description for interfaces also appears in the output from the more system:running config privileged EXEC mode command.

SUMMARY STEPS

    1.    enable

    2.    configure terminal

    3.    snmp ifmib ifalias long

    4.    interface type number

    5.    description text-string

    6.    end

    7.    show snmp mib

    8.    show snmp mib ifmib ifindex [type number] [detail] [free-list]


DETAILED STEPS
     Command or ActionPurpose
    Step 1 enable


    Example:
    Device> enable
     

    Enables privileged EXEC mode.

    • Enter your password if prompted.

     
    Step 2 configure terminal


    Example:
    Device# configure terminal
     

    Enters global configuration mode.

     
    Step 3 snmp ifmib ifalias long


    Example:
    Device(config)# snmp ifmib ifalias long
     

    Configures the Interfaces MIB (IF-MIB) on the system to return ifAlias values of longer than 64 characters to a Network Management System.

    • If the ifAlias values are not configured using the snmp ifmib ifalias long command, the ifAlias description will be restricted to 64 characters.

     
    Step 4 interface type number


    Example:
    Device(config)# interface ethernet 2/4
     

    Enters interface configuration mode.

    • The form of this command varies depending on the interface being configured.

     
    Step 5 description text-string


    Example:
    Device(config)# description This text string description can be up to 256 characters long
     

    Configures a free-text description of the specified interface.

    • This description can be up to 240 characters in length and is stored as the ifAlias object value in the IF-MIB.

    • If the ifAlias values are not configured using the snmp ifmib ifalias long command, the ifAlias description for SNMP set and get operations is restricted to 64 characters, although the interface description is configured for more than 64 characters by using the description command.

     
    Step 6 end


    Example:
    Device(config)# end
     

    Exits global configuration mode.

     
    Step 7 show snmp mib


    Example:
    Device# show snmp mib
     

    Displays a list of MIB module instance identifiers registered on your system.

    • The resulting display could be lengthy.

     
    Step 8 show snmp mib ifmib ifindex [type number] [detail] [free-list]


    Example:
    Device# show snmp mib ifmib ifindex Ethernet 2/0
     

    Displays the Interfaces MIB ifIndex values registered on your system for all interfaces or the specified interface.

     

    Examples

    The following example lists the MIB module instance identifiers registered on your system. The resulting display could be lengthy. Only a small portion is shown here. 

    Device# show snmp mib
system.1
system.2
sysUpTime
system.4
system.5
system.6
system.7
system.8
sysOREntry.2
sysOREntry.3
sysOREntry.4
interfaces.1
ifEntry.1
ifEntry.2
ifEntry.3
ifEntry.4
ifEntry.5
ifEntry.6
ifEntry.7
ifEntry.8
ifEntry.9
ifEntry.10
ifEntry.11
 --More-- 
captureBufferEntry.2
captureBufferEntry.3
captureBufferEntry.4
captureBufferEntry.5
captureBufferEntry.6
captureBufferEntry.7
capture.3.1.1
eventEntry.1
eventEntry.2
eventEntry.3
eventEntry.4
eventEntry.5
eventEntry.6
eventEntry.7
logEntry.1
logEntry.2
logEntry.3
logEntry.4
rmon.10.1.1.2
rmon.10.1.1.3
rmon.10.1.1.4
rmon.10.1.1.5
rmon.10.1.1.6
rmon.10.1.1.7
rmon.10.2.1.2
rmon.10.2.1.3
rmon.10.3.1.2

    The following example shows output for the Interfaces MIB ifIndex values registered on a system for a specific interface: 

    Device# show snmp mib ifmib ifindex Ethernet 2/0
Ethernet2/0: Ifindex = 2

    The following example shows output for the Interfaces MIB ifIndex values registered on a system for all interfaces: 

    Device# show snmp mib ifmib ifindex
ATM1/0: Ifindex = 1
ATM1/0-aal5 layer: Ifindex = 12
ATM1/0-atm layer: Ifindex = 10
ATM1/0.0-aal5 layer: Ifindex = 13
ATM1/0.0-atm subif: Ifindex = 11
ATM1/0.9-aal5 layer: Ifindex = 32
ATM1/0.9-atm subif: Ifindex = 31
ATM1/0.99-aal5 layer: Ifindex = 36
ATM1/0.99-atm subif: Ifindex = 35
Ethernet2/0: Ifindex = 2
Ethernet2/1: Ifindex = 3
Ethernet2/2: Ifindex = 4
Ethernet2/3: Ifindex = 5
Null0: Ifindex = 14
Serial3/0: Ifindex = 6
Serial3/1: Ifindex = 7
Serial3/2: Ifindex = 8
Serial3/3: Ifindex = 9

    Troubleshooting Tips

    To monitor SNMP trap activity in real time for the purposes of troubleshooting, use the SNMP debug commands, including the debug snmp packet EXEC command. For documentation of SNMP debug commands, see the Cisco IOS Debug Command Reference.

    Configuration Examples for Circuit Interface Identification Persistence for SNMP

    Example Configuring IfAlias Long Name Support

    In the following example a long description is applied to the Fast Ethernet interface in slot 1, port adapter 0, and port 0: 

    Device# configure terminal
Device(config)#interface FastEthernet1/0/0
Device(config-if)# description FastEthernet1/0/0 this is a test of a description that exceeds 64 characters in length
Device(config-if)#ip address 192.168.134.55 255.255.255.0 
Device(config-if)#no ip directed-broadcast
Device(config-if)#no ip route-cache distributed

    Assuming that ifAlias long name support is not yet enabled (the default), the following example shows the results of a mibwalk operation from an NMS: 

    ***** SNMP QUERY STARTED *****
 .
 .
 .
 ifXEntry.18.10 (octets) (zero-length) 
 ifXEntry.18.11 (octets) Fastethernet1/0/0 this is a test of a description that exceeds 64 ch
 ifXEntry.18.12 (octets) (zero-length)
 .
 .
 .

    The following output shows the description that is displayed at the CLI: 

    Device# show interface FastEthernet0/0/0 

FastEthernet1/0/0 is administratively down, line protocol is down 
  Hardware is Lance, address is 0010.7b4d.7046 (bia 0010.7b4d.7046)
  Description: FastEthernet1/0/0 this is a test of a description that exceeds 64 chh
  MTU 1500 bytes, BW 10000 Kbit, DLY 1000 usec, 
     reliability 252/255, txload 1/255, rxload 1/255
 .
 .
 .

    In the following example, ifAlias long name support is enabled and the description is displayed again: 

    Device(config)# snmp ifmib ifalias long
Device(config)#interface FastEthernet1/0/0 
Device(config-if)# description FastEthernet1/0/0 this is a test of a description that exceeds
64 characters in length 
Device(config)#end 

Device# show interface FastEthernet1/0/0 

FastEthernet1/0/0 is administratively down, line protocol is down 
  Hardware is Lance, address is 0010.7b4d.7046 (bia 0010.7b4d.7046)
  Description: FastEthernet1/0/0 this is a test of a description that exceeds 64 characters in length
  MTU 1500 bytes, BW 10000 Kbit, DLY 1000 usec, 
     reliability 252/255, txload 1/255, rxload 1/255
 .
 .
 .
***** SNMP QUERY STARTED *****
 .
 .
 .
 ifXEntry.18.10 (octets) (zero-length) 
 ifXEntry.18.11 (octets) FastEthernet1/0/0 this is a test of a description that exceeds 64 characters in length
 ifXEntry.18.12 (octets) (zero-length)
 .
 .
 .

    Example Configuring IfIndex Persistence

    The following example shows how to enable IfIndex persistence globally: 

    Device# configure terminal
Device(config)# snmp-server ifindex persist

    The following example shows how to enable IfIndex persistence on the Ethernet interface: 

    Device# configure terminal
Device(config)# interface ethernet 0/1
Device(config)# snmp-server ifindex persist

    Additional References

    Related Documents

    Related Topic

    Document Title

    Cisco IOS commands

    Cisco IOS Master Command List, All Releases

    SNMP commands: complete command syntax, command mode, command history, defaults, usage guidelines, and examples

    Cisco IOS SNMP Command Reference

    Cisco implementation of RFC 1724, RIP Version 2 MIB Extensions

    RIPv2 Monitoring with SNMP Using the RFC 1724 MIB Extensions feature module

    DSP Operational State Notifications for notifications to be generated when a digital signaling processor (DSP) is used

    DSP Operational State Notifications feature module

    Standards and RFCs

    Standard/RFC

    Title

    CBC-DES (DES-56) standard

    Symmetric Encryption Protocol

    STD: 58

    Structure of Management Information Version 2 (SMIv2)

    RFC 1067

    A Simple Network Management Protocol

    RFC 1091

    Telnet terminal-type option

    RFC 1098

    Simple Network Management Protocol (SNMP)

    RFC 1157

    Simple Network Management Protocol (SNMP)

    RFC 1213

    Management Information Base for Network Management of TCP/IP-based internets:MIB-II

    RFC 1215

    Convention for defining traps for use with the SNMP

    RFC 1901

    Introduction to Community-based SNMPv2

    RFC 1905

    Common Management Information Services and Protocol over TCP/IP (CMOT)

    RFC 1906

    Telnet X Display Location Option

    RFC 1908

    Simple Network Management Protocol (SNMP)

    RFC 2104

    HMAC: Keyed-Hashing for Message Authentication

    RFC 2206

    RSVP Management Information Base using SMIv2

    RFC 2213

    Integrated Services Management Information Base using SMIv2

    RFC 2214

    Integrated Services Management Information Base Guaranteed Service Extensions using SMIv2

    RFC 2271

    An Architecture for Describing SNMP Management Frameworks

    RFC 2570

    Introduction to Version 3 of the Internet-standard Network Management Framework

    RFC 2578

    Structure of Management Information Version 2 (SMIv2)

    RFC 2579

    Textual Conventions for SMIv2

    RFC 2580

    Conformance Statements for SMIv2

    RFC 2981

    Event MIB

    RFC 2982

    Distributed Management Expression MIB

    RFC 3413

    SNMPv3 Applications

    RFC 3415

    View-based Access Control Model (VACM) for the Simple Network Management Protocol (SNMP)

    RFC 3418

    Management Information Base (MIB) for the Simple Network Management Protocol (SNMP)

    MIBs

    MIB

    MIBs Link

    • Circuit Interface Identification MIB

    • Cisco SNMPv2

    • Ethernet-like Interfaces MIB

    • Event MIB

    • Expression MIB Support for Delta, Wildcarding, and Aggregation

    • Interfaces Group MIB (IF-MIB)

    • Interfaces Group MIB Enhancements

    • MIB Enhancements for Universal Gateways and Access Servers

    • MSDP MIB

    • NTP MIB

    • Response Time Monitor MIB

    • Virtual Switch MIB

    To locate and download MIBs for selected platforms, releases, and feature sets, use Cisco MIB Locator found at the following URL:

    http:/​/​www.cisco.com/​go/​mibs

    Technical Assistance

    Description

    Link

    The Cisco Support and Documentation website provides online resources to download documentation, software, and tools. Use these resources to install and configure the software and to troubleshoot and resolve technical issues with Cisco products and technologies. Access to most tools on the Cisco Support and Documentation website requires a Cisco.com user ID and password.

    http:/​/​www.cisco.com/​cisco/​web/​support/​index.html

    Feature Information for Circuit Interface Identification Persistence for SNMP

    The following table provides release information about the feature or features described in this module. This table lists only the software release that introduced support for a given feature in a given software release train. Unless noted otherwise, subsequent releases of that software release train also support that feature.

    Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to . An account on Cisco.com is not required.
    Table 1 Feature Information for Circuit Interface Identification Persistence for SNMP

    Feature Name

    Releases

    Feature Information

    Circuit Interface Identification Persistence for SNMP

    12.1(3)T

    15.0(1)S

    The Circuit Interface Identification Persistence for SNMP feature can be used to identify individual circuit-based interfaces for SNMP monitoring.