[c-nsp] problem with VPC port-channel between Cisco 3550 and pair of Nexus 5020

[Martin Clifton]

Hi,

You may find the Nexus 5020 has blocked the port because it has received a
spanning-tree bpdu from the 3560.

You could apply the following command on the 3550 uplink:
spanning-tree bpdufilter enable

Whilst this is safe enough on a single link, I would be very careful about
applying it in a redundant/port-channeled scenario.

Regards, Martin








-----Original Message-----
From: Tom Mikelson <tmikelson at gmail.com>
Date: Wed, 23 May 2012 11:54:32 -0600
To: <cisco-nsp at puck.nether.net>
Subject: [c-nsp] problem with VPC port-channel between Cisco 3550 and pair
of Nexus 5020

>Physical links are up, cdp neighbor shows all devices
>Nexus 5020 pair configured with working VPC link on VLAN 11.
>Port-channel 64 on both Nexus 5020s show blocked for spanning-tree VLAN
>11.
>
>***** Nexus 5020s *****
>
>interface port-channel64
>  description TEST
>  switchport mode trunk
>  switchport trunk allowed vlan 11
>  speed 1000
>  vpc 64
>
>interface Ethernet1/8
>  description TEST
>  switchport mode trunk
>  switchport trunk allowed vlan 11
>  speed 1000
>  channel-group 64 mode active
>
>***** Cisco 3550 *****
>
>interface Port-channel64
> description TEST
> switchport trunk encapsulation dot1q
> switchport trunk allowed vlan 11
> switchport mode trunk
>!
>interface GigabitEthernet0/1
> description TEST_to_5020_A
> switchport trunk encapsulation dot1q
> switchport trunk allowed vlan 11
> switchport mode trunk
> channel-group 64 mode active
>!
>interface GigabitEthernet0/2
> description TEST_to_5020_B
> switchport trunk encapsulation dot1q
> switchport trunk allowed vlan 11
> switchport mode trunk
> channel-group 64 mode active
>!
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