6500 Portchannel Allowed VLANs Trunk

Answered Question
Oct 26th, 2009

I am having a problem getting allowed trunks to show up in my configuration

I am setting up the portchannels on the 6513 to trunk. I have them set for encap dot1q, switchport, and switchport mode trunk.

When I go to add the switchport trunk allowed vlan add 2,100,110... it doesnt get added.

When I issue the show interface port-channel 6 trunk it shows that no vlans are allowed?

Probably an easy question that I am just missing.

The port channel is shut down but is not yet connected to the other switch so it is admin up protocol down.

Thanks

James

I have this problem too.
0 votes
Correct Answer by glen.grant about 7 years 1 month ago

You could try removing all vlans but those 3 and see what happens

switchport trunk allowed vlan remove 1,3-99,101-109,111-1025 etc...

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abbey1234 Mon, 10/26/2009 - 15:09

possible example of syntax:

Port-channel64

switchport

switchport trunk encapsulation dot1q

switchport trunk allowed vlan 123, 124, 125

switchport mode trunk

switchport nonegotiate

no ip address

jfraasch Tue, 10/27/2009 - 05:30

That's exactly the command set I used. Didnt show up in the running config.

abbey1234 Tue, 10/27/2009 - 07:32

Thanks for the feedback. Perhaps if you provide us a copy of your running config we can see something missing... i.e. port shutdown or no vlan in vtp domain database.......

jason.henderson Mon, 10/26/2009 - 15:26

Have you tried allowing the vlans on the interfaces that belong to the port-channel? Make sure they're all the same config.

jfraasch Tue, 10/27/2009 - 05:32

Shouldn't have to do that really. That's kind of the purpose of the portchannel in the first place. I will have about 16 different port channels on each 6513. Largest portchannel will be 4 ports. I'd prefer to just configure the portchannel with the VLANs as opposed to all the physical ports.

Correct Answer
glen.grant Mon, 10/26/2009 - 15:57

You could try removing all vlans but those 3 and see what happens

switchport trunk allowed vlan remove 1,3-99,101-109,111-1025 etc...

jfraasch Tue, 10/27/2009 - 05:33

Interesting thought. Will give it a shot. But right now it says I have NONE allowed. Maybe a little reverse psychology will do the switch good!

jfraasch Tue, 10/27/2009 - 09:09

Glen you were definitely on the right track. I brought up the other side of the portchannel so I could troubleshoot.

What it ended up being is that on CoreA I had VLANs 1-4094 allowed and on CoreB I had only the VLANs I wanted to allow in the config.

I remembered that some point in the early troubleshooting of this issue that I put the switchport trunk allowed VLAN add all command. Unfortunately for Cisco users, this actual command does not show up in the running config.

I ended up doing a switchport trunk allowed vlan none command then issued the switchport trunk allowed vlan 2,100,110 and now only those correct VLANs are on the trunk.

Thanks for everyone's help. Now I am off to configure the HA for the FWSM on the two Chassis. I am sure you will hear from me again soon.

Five stars to Glen! Thanks.

James

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