Finding ARP count and ARP PPS on Cisco ASR9000

ARP (Address Resolution Protocol) is a network protocol used to map an IP address (Layer 3) to a corresponding MAC address (Layer 2) on a local area network (LAN). These are sample ways to find ARP on Cisco ASR 9000 running on IOS-XR.

1. To find out the ARP statistics for a particular linecard, the command would be:

show arp traffic location 0/X/CPU0

where X is the Slot number

Example:

RP/0/RSP0/CPU0:ASR9000#show arp traffic location 0/7/CPU0

ARP statistics:
Recv: 2493913945 requests, 2796126129 replies
Sent: 1318068385 requests, 2425540236 replies (0 proxy, 337802214 local proxy, 15 gratuitous)
Subscriber Interface:
0 requests recv, 0 replies sent, 0 gratuitous replies sent
Resolve requests rcvd: 1172404706
Resolve requests dropped: 622762
Errors: 0 out of memory, 0 no buffers, 0 out of sunbet

ARP cache:
Total ARP entries in cache: 13240
Dynamic: 12566, Interface: 10, Standby: 0
Alias: 0, Static: 0, DHCP: 0

IP Packet drop count for node 0/7/CPU0: 1168962917

Total ARP-IDB:1

Based on the output above, there’s total of 13240 ARP count  on this Linecard 7

Can do some filtering:

show arp traffic location 0/X/CPU0 | include “Total ARP “

RP/0/RSP0/CPU0:ASR9000#show arp traffic location 0/7/CPU0 | include “Total ARP “
Total ARP entries in cache: 13240

This should co-relate to the number of ARP on the interfaces on Linecard Slot 7 by using this command:

show arp <interface> location 0/X/CPU0 | utility wc lines

2. To find out the ARP PPS(Packets per Sec) for a particular linecard, the command would be:

show controllers NP counters all location 0/X/CPU0

where X is the Slot number
This command will show the Network Processor (NP) packet counter capture

Example:

RP/0/RSP0/CPU0:ASR9000#show controllers NP counters all location 0/7/CPU0 | include “ARP|Node|global”

Node: 0/7/CPU0:
—————————————————————-

Show global stats counters for NP0, revision v2
Last clearing of counters for this NP: NEVER
Read 103 non-zero NP counters:
Offset Counter FrameValue Rate (pps)
——————————————————————————-
Node: 0/7/CPU0:
Show global stats counters for NP0, revision v4
778 ARP 31373746421 158
779 ARP_EXCD 795870584 0
780 RARP 83 0

Based on the output above, there’s total of 158 ARP Packets per Sec(PPS) on Linecard 7. This is very useful on checking if there’s any dropped or  how many ARP PPS per linecard as there’s some hardware limitation for some Cisco cards of 1000 PPS.

To better understand what counter description means, the command would be:

show controllers np descriptions location 0/X/CPU0

Example:

RP/0/RSP0/CPU0:ASR9000#show controllers np descriptions location 0/7/CPU0 | i ARP

ARP Drop Punt Punt Ingress ARP protocol frames – layer3 interface only
ARP_EXCD Drop Punt Frames that would normally be punted to CPU but were dropped due to Control Plane Policing. The pps policed limit is aggregated across the NP for all punts of this reason/protocol. (See description of counter without _EXCD for details of the frame being punted)
RARP Drop Punt Punt Ingress Reverse ARP protocol frames – layer3 interface only