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Cisco Bug: CSCtd22993 - SNMP ifIndex for certain serial interfaces becomes inactive

Last Modified

Oct 29, 2015

Products (1)

  • Cisco IOS

Known Affected Releases

12.2(33)SRC3 12.2(33)SRC4 12.2(33)SXH 12.2SXH 12.2SXI

Description (partial)


This bug is very similar to CSCsx13834. However, it is for different kind of PAs, such as PA-4E1G-75 or -120.
It is very easy to reproduce. And the workaround mentioned in CSCsx13834 does not help.

Basically, the serial module in the slot2 will become inactive and cannot be accessed via SNMP.

Here is a quick way to see the problem where "Active=no" means, no ifIndex can be polled via SNMP.

Router#sh snmp mib ifmib ifindex detail | in Serial2
Description                     ifIndex  Active  Persistent  Saved
Serial2/1/3                      57     no       disabled      no
Serial2/1/1                      55     no       disabled      no
Serial2/1/2                      56     no       disabled      no
Serial2/1/0                      54     no       disabled      no

Slot 1 ports, on the other hand, are all fine, where "Active=yes":

Router#sh snmp mib ifmib ifindex detail | in Serial1
Description                     ifIndex  Active  Persistent  Saved
Serial1/1/6                      42     yes      disabled      no
Serial1/1/4                      40     yes      disabled      no
Serial1/1/2                      38     yes      disabled      no
Serial1/1/0                      36     yes      disabled      no
Serial1/1/7                      43     yes      disabled      no
Serial1/1/5                      41     yes      disabled      no
Serial1/1/3                      39     yes      disabled      no
Serial1/1/1                      37     yes      disabled      no


This is only observed on PAs such as PA-4E1G-75 or -120. Here is a show mod example.

Router#sh mod
Mod Ports Card Type                              Model 
Serial No.
--- ----- -------------------------------------- ------------------ 
   1    0  2 port adapter Enhanced FlexWAN        WS-X6582-2PA 
   2    0  2 port adapter Enhanced FlexWAN        WS-X6582-2PA 
   3   24  CEF720 24 port 1000mb SFP              WS-X6724-SFP 
   6    2  Route Switch Processor 720 (Active)    RSP720-3C-GE 

Mod MAC addresses                       Hw    Fw           Sw 
--- ---------------------------------- ------ ------------ ------------ 
   1  0011.208b.9ec0 to 0011.208b.9eff   1.6   12.2(33)SRC3 12.2(33)SRC3 Ok
   2  0019.55ad.4d90 to 0019.55ad.4dcf   2.3   12.2(33)SRC3 12.2(33)SRC3 Ok
   3  001a.6d73.0b58 to 001a.6d73.0b6f   2.5   12.2(14r)S5  12.2(33)SRC3 Ok
   6  001b.d401.5bf0 to 001b.d401.5bf3   5.2   12.2(33r)SRB 12.2(33)SRC3 Ok
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