SNMP returns incorrect value for the interface when using switchport

[himanshu-s-sahoo]

Hi All,

I have two Cisco C8300-1N1S-4T2X chassis routers, both running same IOS version 17.12.04b. On both devices, I applied the "no switchport" command to convert the interfaces to Layer 3 mode. 

Both interfaces being up and actively passing traffic as verified in CLI. 

There's a discrepancy in SNMP reporting:

• On Router A, SNMPwalk returns the correct administrative and operational status for the interface.
• On Router B, SNMPwalk returns incorrect admin and oper states, which do not match the CLI output, even though the interface is functioning properly.

This inconsistency is impacting accurate SNMP-based monitoring. Please advise or assist in determining the root cause.

[MHM Cisco World]

Can I see 

Show ip interface <>

Show ip interface breif 

From both router

MHM

[himanshu-s-sahoo]

Hi @MHM Cisco World 

Apologies for delay response. Thanks for the replay. Below are the requested outputs. 

====================
Working Router
====================
Router1#Show ip interface Te0/1/2
TenGigabitEthernet0/1/2 is up, line protocol is up
Internet protocol processing disabled
Router1#Show ip interface brief | i Te0/1/2
Te0/1/2 unassigned YES NVRAM up up
Te0/1/2.2024 10.1.48.2 YES NVRAM up up
Te0/1/2.2030 10.1.55.5 YES NVRAM up up
Router1#sh int Te0/1/2
TenGigabitEthernet0/1/2 is up, line protocol is up
Hardware is C-NIM-4X, address is 28b5.916a.650a (bia 28b5.916a.650a)
Description: TO ISP
MTU 1500 bytes, BW 500000 Kbit/sec, DLY 10 usec,
reliability 255/255, txload 2/255, rxload 1/255
Encapsulation 802.1Q Virtual LAN, Vlan ID 1., loopback not set
Keepalive not supported
Full Duplex, 1000Mbps, link type is force-up, media type is LX
output flow-control is on, input flow-control is on
ARP type: ARPA, ARP Timeout 04:00:00
Last input 00:00:00, output 00:00:00, output hang never
Last clearing of "show interface" counters never
Input queue: 0/375/0/0 (size/max/drops/flushes); Total output drops: 613944
Queueing strategy: Class-based queueing
Output queue: 0/40 (size/max)
30 second input rate 3650000 bits/sec, 842 packets/sec
30 second output rate 5595000 bits/sec, 1258 packets/sec
5147775294 packets input, 2540709135422 bytes, 0 no buffer
Received 4 broadcasts (0 IP multicasts)
0 runts, 0 giants, 0 throttles
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
0 watchdog, 26482 multicast, 0 pause input
8920656431 packets output, 5035013927034 bytes, 0 underruns
Output 9 broadcasts (0 IP multicasts)
0 output errors, 0 collisions, 2 interface resets
0 unknown protocol drops
0 babbles, 0 late collision, 0 deferred
0 lost carrier, 0 no carrier, 0 pause output
0 output buffer failures, 0 output buffers swapped out

====================
Non-working Router
====================
Router2#Show ip interface Te0/1/2
TenGigabitEthernet0/1/2 is up, line protocol is up
Internet protocol processing disabled
Router2#Show ip interface brief | i Te0/1/2
Te0/1/2 unassigned YES unset up up
Te0/1/2.2024 10.1.4.50 YES manual up up
Te0/1/2.2030 10.1.4.54 YES manual up up
Router2#sh int Te0/1/2
TenGigabitEthernet0/1/2 is up, line protocol is up
Hardware is C-NIM-4X, address is 28b5.9169.db3a (bia 28b5.9169.db3a)
Description: TO ISP
MTU 1500 bytes, BW 1000000 Kbit/sec, DLY 10 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation 802.1Q Virtual LAN, Vlan ID 1., loopback not set
Keepalive not supported
Full Duplex, 1000Mbps, link type is force-up, media type is LX
output flow-control is on, input flow-control is on
ARP type: ARPA, ARP Timeout 04:00:00
Last input 00:00:00, output 00:00:00, output hang never
Last clearing of "show interface" counters 5w3d
Input queue: 0/375/0/0 (size/max/drops/flushes); Total output drops: 0
Queueing strategy: Class-based queueing
Output queue: 0/40 (size/max)
30 second input rate 1238000 bits/sec, 452 packets/sec
30 second output rate 3180000 bits/sec, 841 packets/sec
1214932147 packets input, 549299814468 bytes, 0 no buffer
Received 0 broadcasts (0 IP multicasts)
0 runts, 0 giants, 0 throttles
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
0 watchdog, 18406 multicast, 0 pause input
1880463506 packets output, 826736532841 bytes, 0 underruns
Output 0 broadcasts (0 IP multicasts)
0 output errors, 0 collisions, 0 interface resets
0 unknown protocol drops
0 babbles, 0 late collision, 0 deferred
0 lost carrier, 0 no carrier, 0 pause output
0 output buffer failures, 0 output buffers swapped out

[MHM Cisco World]

One NVRAM (work) and other manual (not work)

I Dont know but I think snmp see interface different because of that 

Try WR config for non work router make interface as NVRAM then check snmpwalk

MHM

[Enes Simnica]

hello @himanshu-s-sahoo man. U have to first verify SNMP configuration consistency between both routers with "show run | include snmp". Check for differences in community strings, views, or access controls. After that go ahead and confirm interface indexing matches reality using "show snmp mib ifmib ifindex" because sometimes SNMP uses different indexes than CLI. And u should clear any stale SNMP data with "clear snmp counters".

Dont forget that this could be caused by an SNMP cache issue (try restarting the SNMP process with "process restart snmpd"), an IOS-XE bug (check Cisco's bug tracker for 17.12.04b IF-MIB issues), or interface role misclassification (even in L3 mode). As a workaround, you might need to create custom SNMP views or consider upgrading to a more stable IOS-XE version if this is a known bug. and and the end, as usual for immediate monitoring, u could script around it by correlating CLI output with SNMP data.

https://www.cisco.com/c/en/us/support/web/tools/snmp/help/index.html

https://www.cisco.com/c/en/us/support/routers/catalyst-8300-series-edge-platforms/products-system-message-guides-list.html

https://www.cisco.com/c/en/us/td/docs/app_ntwk_services/waas/waas/v511/configuration/guide/cnfg/SNMP.pdf 

hope it helps man..

-Enes

[himanshu-s-sahoo]

Hi @Enes Simnica 

Thanks for your replay.

I found a bug related to this issue, but my router's IOS version is different.

CSCwk28794 : Bug Search Tool

I have several devices in my network with the same model and IOS, but I'm still trying to figure out why only one router is reporting this issue.