Etherchannel in Cisco 2921

[mohammad saeed]

Ho Guys,

today I tried to create etherchannel connection between 6509-e and 2921 router VG, but after I configured 2921 for L3 etherchannel and wrote : 

show etherchannel summary, no channels appeared.

I created L2 etherchannel in 6509-e.

in the core switch i can see the port channel as L2, but in 2921 I can't see.

what is the problem?

Thanks

Mohammad

[Peter Paluch]

Hi Mohammad,

I believe that on the 2921, the show etherchannel summary would only display EtherChannels configured on added switching modules (EHWIC or SM). A Port-channel configured on top of routed ports is not displayed in this output - I have the same experience with 2811 running 15.3(3)XB12 IOS.

You can get somewhat more detail about your Port-channel using the show interface po1 command, substituting 1 with your actual Port-channel number.

Keep also in mind that Cisco routers generally do not support PAgP or LACP, and so this EtherChannel must be configured using mode on at the Catalyst 6509.

Best regards,
Peter

[mohammad saeed]

Hi Peter,

Actually I did it L3 etherchannel in both (router and 6509) with mode on. but when I disconnected one interface I lost the connection with CUCM from VG. i don't know where is the problem!

[mohammad saeed]

Hi Peter,

I noticed something, gig0/0 in router is ok but after I removed and gig0/1 can't reach to CUCM, and the port channel is up!

After I returned back gig0/0 also I couldn't ping to CUCM but if I removed gig0/1 and connect gig0/0 the connection come back again.

I noticed something about member number inside port channel,

gig0/0 member 0

gig0/1 member 1 

any Idea please,

Thanks 

Mohammad

[Peter Paluch]

Mohammad,

I am not sure what is happening. Have you configured port-channel load-balance command both on the router and the switch to take both source and destination IP into account?

We need to do some very basic connectivity testing as I did not fully comprehend your descriptions of the connectivity outage and exact circumstances in which it was experienced. Ideally run a continuous ping between the router and the 6509 and disconnect/reconnect a single link, and describe the connectivity result for each state of each link (link X/Y, status connected/disconnected).

Best regards,

Peter