N2248 active-active configuration question

[csthomas]

I have a pair of 5548s connected as w/ vPC.  I have some 2248s which I wish to connect the the 5548 pair in active-active.  Each 2248 is connected to one port on each of the 5548s.  The 5548 ports are configured as a port channel. vPC display seems to indicate vPC is working. My problem is the 2248s are each online to only one 5548.  If I shutdown their port on which they are "online" to the 5548, they switch to "online" on the other 5548. (both 5548 configurations are identical, except for items like switch name.)

How do I config the 2248s to connect via etherchannel to the 5548s, and to thereby come up online to both 5548s at the same time?  What am I doing wrong?  I'm happy to post configuration if that would help.

/Chris Thomas, UCLA

[Prashanth Krishnappa]

Please post configurations, show vpc and show fex output from both 5548s

[csthomas]

My problem was the documentation is comewhat unclear on how to configure the 2248s.  It is necessary to configure an identical FEX and port-channel on each 5548.  The port-channel defs need to have a matching "vpc n" on each 5548.  This statement has nothing to do with the vPC domain number, and must be unique for each 2248.  Once this is added, the 2248s come up online to both 5548s at the same time.  (There doesn't seem to be a command which specifically says that the 2248s are connected in etherchannel mode.)  (The vpn n is how vPC knows which ports are associated with each port-channel.)

[b.sawyers]

How about:

!

fex 100

  pinning max-links 1

  description "FEX0100"

!

interface port-channel100

  switchport mode fex-fabric

  vpc 100

  fex associate 100

!

interface Ethernet1/25

  switchport mode fex-fabric

  fex associate 100

  channel-group 100

!

once VPC is set up.