Segment Routing -SNMP data

[prathi]

Hi @Harold Ritter ,

Greetings !!!!!!!!

I have one query with segment routing forwarding data.  I am sending some bytes of data(1500000) from XRV1 to XRv2 via SRpolicy tunnel .I see same count is updated in SR-TE forwarding database. But when i do SNMPwalk to ifmib oid , i am getting  different value for interface  SRTE inteface(srte_c_10_ep_30.30.30.1) which is created for destination XRV2.We noticed 60000 bytes of data additionally in snmp counter (out octets) i.e 1560000.

As traffic is going via tunnel interface srte_c_10_ep_30.30.30.1 , we did SNMPwalk to this interface index for out octets. 

Just want to understand why there is difference between CLI output and SNMP counter output. Below is the topology.

XRV1(6.6.3)--------XRV2(6.6.3)

SR-TE Policy Forwarding database
--------------------------------

Color: 10, End-point: 30.30.30.1
Name: srte_c_10_ep_30.30.30.1
Binding SID: 24008
Active LSP:
Candidate path:
Preference: 100 (configuration)
Name: Nokia
Local label: 24007
Segment lists:
SL[0]:
Name: dynamic
Packets/Bytes Switched: 15000/1500000  ================>
Paths:
Path[0]:
Outgoing Label: Pop
Outgoing Interface: GigabitEthernet0/0/0/1
Next Hop: 100.100.101.11
Switched Packets/Bytes: 15000/1500000
FRR Pure Backup: No
ECMP/LFA Backup: No
Label Stack (Top -> Bottom): { Pop }

Policy Packets/Bytes Switched: 15000/1500000

RP/0/RP0/CPU0:xrv9k1#exit
Connection to 172.20.20.61 closed.
[root@root-k8sc-Cisco ~]# snmpwalk -v2c -c auto 172.20.20.61 1.3.6.1.2.1.31.1.1.1.10.6
IF-MIB::ifHCOutOctets.6 = Counter64: 1560000        =================> 60000 bytes additionally added

RP/0/RP0/CPU0:xrv9k1#show ipv4 interface brief
Mon Feb 10 21:45:29.330 UTC

Interface IP-Address Status Protocol Vrf-Name
srte_c_10_ep_30.30.30.1 20.20.20.1 Up Up default 
Loopback0 20.20.20.1 Up Up default

RP/0/RP0/CPU0:xrv9k1#show snmp interface
ifName : FINT0/RP0/CPU0 ifIndex : 1
ifName : MgmtEth0/RP0/CPU0/0 ifIndex : 3
ifName : GigabitEthernet0/0/0/0 ifIndex : 7
ifName : GigabitEthernet0/0/0/1 ifIndex : 8
ifName : GigabitEthernet0/0/0/2 ifIndex : 9
ifName : GigabitEthernet0/0/0/2.11 ifIndex : 13
ifName : GigabitEthernet0/0/0/2.21 ifIndex : 14
ifName : GigabitEthernet0/0/0/2.22 ifIndex : 16
ifName : srte_c_10_ep_30.30.30.1 ifIndex : 6   ===============> 

[Harold Ritter]

Hi @prathi .

Here's the description of ifHCOutOctets from RFC2233:

 "The total number of octets transmitted out of the
               interface, including framing characters.  This object
               is a 64-bit version of ifOutOctets.

So the additional characters reported by the ifHCOutOctets is due to the framing characters.

Regards, 

[prathi]

Thank you so much @Harold Ritter for valuable info

[Harold Ritter]

You are very welcome @prathi and thanks for the feedback