[c-nsp] SNMP and interface description - IOS-XR

[Hank Nussbacher]

In IOS 12.2(33)SRE7a in order to read an interface description we did:
  snmpwalk -v 2c -c <snmp read community> rtr1 .1.3.6.1.4.1.9.2.2.1.1.28

[This is the Cisco specific  locIfDescr]

SNMPv2-SMI::enterprises.9.2.2.1.1.28.3 = STRING: "vidcast via 
vidcast-pix  (Rack #6)"

but we can't find the proper MIB in Cisco IOS XR Software, Version 5.1.3.

Any clue would be appreciated.

Thanks,
Hank