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check the port-channel utilization

Hi Guys,

              I have recently installed cat6500 core switch and i had to connect it to the old core for some reason with port-channel.

The issue is I still have complains of the slowness of the network related to the port-channel.

anyway, before adding new port i need to know how to check the ports utilization per port and how the load balance work?

Everyone's tags (2)
Cisco Employee

Fiza,I would like to start


I would like to start investigation on why the slowness:

1- Is the slowness occuring on all the PC's?
2- Is that for specific vlans are for all the vlans?
3- Do you get the same issue when you connect the PC directly to the Switch?
4- Check the CPU/STP issue on the box.
5- Check for any drops on the interfaces or fabric or modules

Few commands I would suggest to check:

a- Check the utilization of the interface:
sh int t1/1 | in input rate|output rate

b-Check the Port-channel utilization:
show int po100 | in input rate|output rate

c- Show proc cpu sorted |  ex 0.00 .. & ( remote command switch show proc cpu sorted | ex 0.00)==Check for cpu utlization.

d- Show interface | include line|drops   ( Check if any vlan/interface are having input drops)

e- show spann det | in ieee|from|occur|is exec

f- Check for mls cef and mls qos.

g- show interface | in up|drop >>> Check  to see if any interface are dropping any packets

h- Bundling the port would give you the load sharing but not with the performace untill you tweak there parameters.

f- remote command switch show proc cpu sorted | ex 0.00




*************Plz dont forget to rate if this info is helpfull.

Super Bronze

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You should be able to obtain interface load stats for port-channel member ports.

Load balancing depends on the configured load balancing algorithm and the attributes of your traffic.  (I think the 6500 defaults to IP src and dest hash, which if it does, usually works well, but there are situations where it doesn't - e.g. high volume between same pair of hosts.)

BTW, remember a single flow will only use one link.  Also, port-channeling doesn't dynamically load balance, i.e. one link can be running at 100% and dropping packets while the other goes unused.

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