Solved: ASR9K SNMP isisCircIndex not returning data

Mircea Cristian · ‎04-14-2023

Hi all,

We are monitoring the ISIS Adjacency status on an ASR9k using SNMP. The issue appears when pooling the isisISAdjState for some of the entries in the table.

For example, if we walk the table we see all the adjacencies and there corresponding isisCircIndex and isisISAdjIndex, we can see the status for all of the adjacencies (all return value 3 - UP):

-bash-$ snmpwalk -Os -c <community> -v 2c <hostname> .1.3.6.1.2.1.138.1.6.1.1.2
mib-2.138.1.6.1.1.2.21.41 = INTEGER: 3
mib-2.138.1.6.1.1.2.56.7 = INTEGER: 3
mib-2.138.1.6.1.1.2.57.49 = INTEGER: 3
mib-2.138.1.6.1.1.2.58.49 = INTEGER: 3
mib-2.138.1.6.1.1.2.59.49 = INTEGER: 3
mib-2.138.1.6.1.1.2.61.39 = INTEGER: 3
mib-2.138.1.6.1.1.2.62.45 = INTEGER: 3
mib-2.138.1.6.1.1.2.65.81 = INTEGER: 3
mib-2.138.1.6.1.1.2.66.83 = INTEGER: 3
mib-2.138.1.6.1.1.2.67.59 = INTEGER: 3
mib-2.138.1.6.1.1.2.69.53 = INTEGER: 3
mib-2.138.1.6.1.1.2.72.79 = INTEGER: 3
mib-2.138.1.6.1.1.2.83.73 = INTEGER: 3
mib-2.138.1.6.1.1.2.229.13 = INTEGER: 3
mib-2.138.1.6.1.1.2.266.93 = INTEGER: 3
mib-2.138.1.6.1.1.2.269.35 = INTEGER: 3
mib-2.138.1.6.1.1.2.66070.93 = INTEGER: 3

Now, if we pool a specific adjacency using the gathered isisCircIndex and isisISAdjIndex some queries return output and some don't:

-bash-$ snmpwalk -Os -c <community> -v 2c <hostname> .1.3.6.1.2.1.138.1.6.1.1.2.58.49
mib-2.138.1.6.1.1.2.58.49 = INTEGER: 3 --> OK

-bash-$ snmpwalk -Os -c <community> -v 2c <hostname> .1.3.6.1.2.1.138.1.6.1.1.2.229.13
mib-2.138.1.6.1.1.2.229.13 = INTEGER: 3 --> OK

-bash-$ snmpwalk -Os -c <community> -v 2c <hostname> .1.3.6.1.2.1.138.1.6.1.1.2.66070.93
mib-2.138.1.6.1.1.2.66070.93 = No Such Instance currently exists at this OID --> NOT OK

Any ideas on why the box returns data for some adjacencies but not for others?

Thanks,

Cristi

Mircea Cristian · ‎09-26-2023

For anyone having this problem, the bug affecting the platform is CSCur54674, it also affects ASR9k.

https://bst.cisco.com/bugsearch/bug/CSCur54674

Symptom: The results of polling ISIS-MIB::isisISAdjState do not match the output of "show isis adjacency". The adjacency counts do not match.

Mircea

View solution in original post

balaji.bandi · ‎04-14-2023

check below MIB document try the correct value : (see you get right results ?)

https://oidref.com/1.3.6.1.2.1.138.1.6.1.1.2

BB

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Mircea Cristian · ‎04-14-2023

Hi,

When pooling the oid for the entire table, we get the data, but if we try a specific entry for and adjacency (ex: 2.66070.93 or 11.66070.93) no data is returned with (No Such Instance currently exists at this OID).

-bash-4.1$ snmpwalk -Os -c <community> -v 2c <hostname> .1.3.6.1.2.1.138.1.6.1.1 | grep 66070.93
mib-2.138.1.6.1.1.2.66070.93 = INTEGER: 3
mib-2.138.1.6.1.1.3.66070.93 = INTEGER: 0
mib-2.138.1.6.1.1.4.66070.93 = Hex-STRING: A8 A3 77 00 2A 68
mib-2.138.1.6.1.1.5.66070.93 = INTEGER: 2
mib-2.138.1.6.1.1.6.66070.93 = Hex-STRING: 06 22 22 21 02 11
mib-2.138.1.6.1.1.7.66070.93 = Gauge32: 56
mib-2.138.1.6.1.1.8.66070.93 = INTEGER: 2
mib-2.138.1.6.1.1.9.66070.93 = Gauge32: 25
mib-2.138.1.6.1.1.10.66070.93 = Gauge32: 0
mib-2.138.1.6.1.1.11.66070.93 = Timeticks: (363347216) 42 days, 1:17:52.16

-bash-4.1$ snmpwalk -Os -c <community> -v 2c <hostname> .1.3.6.1.2.1.138.1.6.1.1.2.66070.93
mib-2.138.1.6.1.1.2.66070.93 = No Such Instance currently exists at this OID

-bash-4.1$ snmpwalk -Os -c <community> -v 2c <hostname> .1.3.6.1.2.1.138.1.6.1.1.3.66070.93
mib-2.138.1.6.1.1.3.66070.93 = No Such Instance currently exists at this OID

-bash-4.1$ snmpwalk -Os -c <community> -v 2c <hostname> .1.3.6.1.2.1.138.1.6.1.1.4.66070.93
mib-2.138.1.6.1.1.4.66070.93 = No Such Instance currently exists at this OID

-bash-4.1$ snmpwalk -Os -c <community> -v 2c <hostname> .1.3.6.1.2.1.138.1.6.1.1.11.66070.93
mib-2.138.1.6.1.1.11.66070.93 = No Such Instance currently exists at this OID

Thanks,

Cristi

smilstea · ‎04-14-2023

Can you check what adjacency/interface this is related to?

Is the adjacency and interface actually up, you should be able to get this with the circindex and adjindex polling.

This could also be due to CSCvr43874.

I also wanted to make a few comments on polling on the index values, just for reference:

According to RFC444 (IS-IS Adjacency Index Object type), "A unique value identifying the IS adjacency from all other such adjacencies on this circuit. This value is automatically assigned by the system when the adjacency is created."
* This means IsisISAdjIndex cannot be configured as a constant
* The isisISAdjIndex only provides the value of the Adjacency and not the state (up/down).
* Most platforms have SNMP ifIndex persist by default. This prevents the ifIndex from changing even after reload or interface flap.
* However, isisISAdjIndex cannot be configured as a constant. This field is expected to change after every flap and/or reload.

RFC 4444 link – Page 50 and 51:

https://www.rfc-editor.org/rfc/pdfrfc/rfc4444.txt.pdf

Recommendations:

1. Use isisISAdjState to poll for the status of the ISIS link instead of isisISAdjIndex

Thanks,

Sam

Mircea Cristian · ‎04-20-2023

Hello,

The interface is up and I checked if there is anything different for this adjacency (on HundredGigE0/7/0/0) from the rest and there is none.
However there is something odd, all other adjacencies on the box have smaller isisCircIndex.
This adjacency is identified by isisCircIndex 66070 (much higher than the rest), all other adjacencies are identified by much smaller isisCircIndex.

-bash-$ snmpwalk -Os -c <community> -v 2c ASR9k .1.3.6.1.2.1.138.1.6.1.1.2
mib-2.138.1.6.1.1.2.21.41 = INTEGER: 3
mib-2.138.1.6.1.1.2.56.7 = INTEGER: 3
mib-2.138.1.6.1.1.2.57.49 = INTEGER: 3
mib-2.138.1.6.1.1.2.58.49 = INTEGER: 3
mib-2.138.1.6.1.1.2.59.49 = INTEGER: 3
mib-2.138.1.6.1.1.2.61.39 = INTEGER: 3
mib-2.138.1.6.1.1.2.62.45 = INTEGER: 3
mib-2.138.1.6.1.1.2.65.81 = INTEGER: 3
mib-2.138.1.6.1.1.2.66.83 = INTEGER: 3
mib-2.138.1.6.1.1.2.67.59 = INTEGER: 3
mib-2.138.1.6.1.1.2.69.53 = INTEGER: 3
mib-2.138.1.6.1.1.2.72.79 = INTEGER: 3
mib-2.138.1.6.1.1.2.83.73 = INTEGER: 3
mib-2.138.1.6.1.1.2.229.13 = INTEGER: 3
mib-2.138.1.6.1.1.2.266.93 = INTEGER: 3
mib-2.138.1.6.1.1.2.269.35 = INTEGER: 3
mib-2.138.1.6.1.1.2.66070.93 = INTEGER: 3

This is the configuration on the box (all adjacencies are configured the same).

RP/0/RSP0/CPU0:ASR9k#sh snmp interface | i 66070 
ifName : HundredGigE0/7/0/0 ifIndex : 66070

RP/0/RSP0/CPU0:ASR9k>#sh run formal | i 0/7/0/0 
Building configuration...
interface HundredGigE0/7/0/0 cdp
interface HundredGigE0/7/0/0 mtu 9216
interface HundredGigE0/7/0/0 service-policy input PM_NAME_IN
interface HundredGigE0/7/0/0 service-policy output PM_NAME_OUT
interface HundredGigE0/7/0/0 ipv4 address <IP> <MASK>
interface HundredGigE0/7/0/0 carrier-delay up 2000 down 0
interface HundredGigE0/7/0/0 load-interval 30
interface HundredGigE0/7/0/0 dampening
router isis <ISIS_INSTANCE> interface HundredGigE0/7/0/0 
router isis <ISIS_INSTANCE> interface HundredGigE0/7/0/0 circuit-type level-2-only
router isis <ISIS_INSTANCE> interface HundredGigE0/7/0/0 bfd minimum-interval 100
router isis <ISIS_INSTANCE> interface HundredGigE0/7/0/0 bfd multiplier 5
router isis <ISIS_INSTANCE> interface HundredGigE0/7/0/0 bfd fast-detect ipv4
router isis <ISIS_INSTANCE> interface HundredGigE0/7/0/0 point-to-point
router isis <ISIS_INSTANCE> interface HundredGigE0/7/0/0 hello-password keychain ISIS-KEYCHAIN
router isis <ISIS_INSTANCE> interface HundredGigE0/7/0/0 address-family ipv4 unicast 
router isis <ISIS_INSTANCE> interface HundredGigE0/7/0/0 address-family ipv4 unicast fast-reroute per-prefix
router isis <ISIS_INSTANCE> interface HundredGigE0/7/0/0 address-family ipv4 unicast fast-reroute per-prefix ti-lfa level 2
router isis <ISIS_INSTANCE> interface HundredGigE0/7/0/0 address-family ipv4 unicast metric 9000 level 2
router isis <ISIS_INSTANCE> interface HundredGigE0/7/0/0 address-family ipv4 unicast mpls ldp sync

The interface is UP and the ISIS adjacency is up.

RP/0/RSP0/CPU0:ASR9k#sh int brief | i "Name|0/7/0/0"
Name State State Type (byte) (Kbps)
Hu0/7/0/0 up up ARPA 9216 100000000

RP/0/RSP0/CPU0:ASR9k#sh isis neighbors | i 0/7/0/0
<neighbor> Hu0/7/0/0 *PtoP* Up 26 L2 Capable

The issue manifest only for this adjacency on this box.

-bash-4.1$ snmpwalk -Os -c <community> -v 2c ASR9k .1.3.6.1.2.1.138.1.6.1.1 | grep 66070.93 
mib-2.138.1.6.1.1.2.66070.93 = INTEGER: 3
mib-2.138.1.6.1.1.3.66070.93 = INTEGER: 0 
mib-2.138.1.6.1.1.5.66070.93 = INTEGER: 2
mib-2.138.1.6.1.1.7.66070.93 = Gauge32: 56
mib-2.138.1.6.1.1.8.66070.93 = INTEGER: 2
mib-2.138.1.6.1.1.9.66070.93 = Gauge32: 23
mib-2.138.1.6.1.1.10.66070.93 = Gauge32: 0
mib-2.138.1.6.1.1.11.66070.93 = Timeticks: (414712598) 47 days, 23:58:45.98


-bash-4.1$ snmpwalk -Os -c <community> -v 2c ASR9k .1.3.6.1.2.1.138.1.6.1.1.66070.93
mib-2.138.1.6.1.1.66070.93 = No Such Object available on this agent at this OID

Thanks for the recommendation, for other boxes we use isisISAdjState (.1.3.6.1.3.37.3.1.1.4) but on this box, the OID is not supported:

-bash-4.1$ snmpwalk -Os -c <community> -v 2c ASR9k .1.3.6.1.3.37.3.1.1.4
experimental.37.3.1.1.4 = No Such Object available on this agent at this OID

The box has two A99-RSP-SE and is on IOS-XR 6.6.3.

We flapped the adjacency and restarted the snmp process on the box but the issue persists.

Thank you,

Cristi

smilstea · ‎04-20-2023

I would suggest getting a show tech routing isis and show tech snmp and opening a tac case, please do the polling just before collecting the show techs.

Sam

Mircea Cristian · ‎09-26-2023

For anyone having this problem, the bug affecting the platform is CSCur54674, it also affects ASR9k.

https://bst.cisco.com/bugsearch/bug/CSCur54674

Symptom: The results of polling ISIS-MIB::isisISAdjState do not match the output of "show isis adjacency". The adjacency counts do not match.

Mircea