Cisco Troubleshooting Commands – 1

1.  Show interface counters protocol status

-Description

This command is an unpublished Cisco command that is available in ver 12.2 and above and shows us the interface and protocol status. As you can see below, each interface is listed with its corresponding list or running protocols.

-Uses

This command can be used to verify that interfaces are participating in the protocols you require them in. A good example would be Spanning Tree. If you have a protocol not participating in Spanning Tree “Fa0/7 below” it could be putting the vlan it participates in at risk for a loop. In this case, the port is not connected.

CA-A31-43W77-36#Show interfaces counters protocol status

Protocols allocated:

Vlan1: Other, IP

Vlan112: Other, IP, ARP

Vlan163: Other, IP, ARP

Vlan251: Other, IP, ARP

FastEthernet0/1: Other, IP

FastEthernet0/2: Other, IP, Spanning Tree

FastEthernet0/3: Other, IP, Spanning Tree

FastEthernet0/4: Other, IP, Spanning Tree

FastEthernet0/5: Other, IP, Spanning Tree

FastEthernet0/6: Other, IP, Spanning Tree

FastEthernet0/7: Other, IP

FastEthernet0/8: Other, IP, Spanning Tree

FastEthernet0/9: Other, IP, Spanning Tree

SG2#show interface counters protocol status

Protocols allocated:

FastEthernet0/0: Other, IP

FastEthernet1/0: Other, IP, ARP, CDP

FastEthernet1/1: Other, IP, ARP, CDP

Loopback1: Other, IP

2. Show interface accounting

-Description

This command gives you a basic break down of each interface and the associated counters for each; broken down by protocol.

-Use

This command gives you the ability to check the detailed information for each interface and allows you to see packets incrementing on a per-protocol basis.

SG2#show interface accounting

Interface FastEthernet0/0 is disabled

FastEthernet1/0

Protocol Pkts In Chars In Pkts Out Chars Out

Other 2 154 139 8340

IP 527 38100 572 45474

ARP 1 60 5 300

CDP 23 7705 24 7992

FastEthernet1/1

Protocol Pkts In Chars In Pkts Out Chars Out

Other 2 154 139 8340

IP 0 0 191 15942

ARP 1 60 5 300

CDP 23 7705 24 7992

Loopback1

Protocol Pkts In Chars In Pkts Out Chars Out

No traffic sent or received on this interface.

Loopback15

Protocol Pkts In Chars In Pkts Out Chars Out

IP 2 104 2 104

3. Show interfaces summary

-Description and Use

This command allows you to see if there are any dropped packets on your interfaces all at one time. It can be used when troubleshooting a link that is exceeding its available bandwidth or something along those lines.

CA-PR-35C51-R1#sho int sum

*: interface is up

IHQ: pkts in input hold queue IQD: pkts dropped from input queue

OHQ: pkts in output hold queue OQD: pkts dropped from output queue

RXBS: rx rate (bits/sec) RXPS: rx rate (pkts/sec)

TXBS: tx rate (bits/sec) TXPS: tx rate (pkts/sec)

TRTL: throttle count

Interface IHQ IQD OHQ OQD RXBS RXPS TXBS TXPS TRTL

———————————————————————

Vlan1 0 0 0 0 0 0 0 0 0

* Vlan5 0 0 0 0 0 0 0 0 0

* Vlan6 1 0 0 0 2000 1 0 0 0

Vlan13 0 0 0 0 0 0 0 0 0

* Vlan15 0 5 0 0 0 0 0 0 1

* Vlan25 0 0 0 0 0 0 0 0 0

* Vlan26 0 0 0 0 0 0 0 0 0

* Vlan27 0 0 0 0 1000 1 8000 16 0

* Vlan32 0 25 0 0 114000 188 0 0 1

* Vlan37 0 0 0 0 0 0 0 0 0

* Vlan39 0 0 0 0 0 0 0 0 0

* Vlan46 0 17 0 0 6000 9 2000 2 1

* Vlan50 0 17 0 0 682000 166 337000 69 1

4. Show interface counters

Description – this command gives you the packet count for each interface and it’s associated IN and OUT count.

Use – This can allow you to look incrementing packets for the entire device without having to go into each interface on its own. It is also nice because it breaks the packets down by type. So if you wanted to check and make sure you are receiving Multicast packets on ports 2, 4, 5 you can watch them all at once.

CA-A31-36#sho int counters

Port InOctets InUcastPkts InMcastPkts InBcastPkts

Fa0/1 0 0 0 0

Fa0/2 9554114 90717 23 1054

Fa0/3 4344241109 41095442 0 138

Fa0/4 2597053412 28027665 87 93379

Fa0/5 5027141741 38715811 62 107699

Port OutOctets OutUcastPkts OutMcastPkts OutBcastPkts

Fa0/1 0 0 0 0

Fa0/2 203190126 156315 57080 7738

Fa0/3 41398983291 303765483 32142064 35229531

Fa0/4 44024460395 69378044 34255762 7820553

Fa0/5 405998091547 2215247117 34245798 6254554

One Response

  1. It’s important to know that IP Accounting has to be enabled on a per interface basis. Also, it causes performance degradation as it requires processing in the CPU. A good thing about Accounting is that it can be configured to report on ACL access violations.

    Great overview, thx…

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