Cisco Is Truncating the ifAlias SNMP OID

May 04, 2007 1 Replies

I think Cisco is truncating the interface descriptions when being pulled via SNMP using the standard oid IF-MIB::ifAlias at 64 characters. Juniper doesn't do the same thing so I don't think it's a requirement of that OID.



Example interface config. interface GigabitEthernet0/2 description This is a test interface descriptoin that is very long. There seems to be a problem with ifalias on Cisco devices truncating the output....



SNMP get using ifAlias IF-MIB::ifAlias.3 = STRING: This is a test interface descriptoin that is very long. There s



SNMP get using the depreciated 1.3.6.1.4.1.9.2.2.1.1.28 from OLD-CISCO- INTERFACES-MIB SNMPv2-SMI::enterprises.9.2.2.1.1.28.3 = STRING: "This is a test interface descriptoin that is very long. There seems to be a problem with ifalias on Cisco devices truncating the output...."



Just wondering if there was a better way to do this via SNMP than to use a depreciated MIB file.



Paul



Cisco is right, see SYNTAC of ifAlias in IF-MIB

ifAlias OBJECT-TYPE SYNTAX DisplayString (SIZE(0..64)) MAX-ACCESS read-write STATUS current DESCRIPTION ... ::= { ifXEntry 18 }

As I remember you have to be lucky to get 64 bytes at all. Several other vendors implemented SYNTAX SnmpAdminString wich is 32 characters long.

Paul Thomas schrieb:

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