I've got a ten gig interface on a 6509 running 12.2(33) configured as a trunk, but I've not been able to add any allowed VLANs as I've done before on other ten gig ports on different 6509 chassis. Am I missing something obvious?
I'm assuming that the reason I'm unable to set the encapsulation to dot1q is because the new hardware doens't support ISL, hence no need. The command to add the VLANs however doesn't get rejected, it just doesn't appear to do anything.
I've tried adding single VLANs and multiples, but no joy. Any ideas?
Here's what I've done:
SWITCH_1631(config)#default int t4/1
Interface TenGigabitEthernet4/1 set to default configuration
SWITCH_1631#sh ru int t4/12
Current configuration : 65 bytes
no ip address
SWITCH_1631(config-if)#switchport mode trunk
SWITCH_1631(config-if)#switchport trunk allowed vlan ?
WORD VLAN IDs of the allowed VLANs when this port is in trunking mode
add add VLANs to the current list
all all VLANs
except all VLANs except the following
none no VLANs
remove remove VLANs from the current list
SWITCH_1631(config-if)#switchport trunk allowed vlan add 700
SWITCH_1631#sh vlan id 700
VLAN Name Status Ports
---- -------------------------------- --------- -------------------------------
700 VLAN_NAME active <snip>
SWITCH_1631#sh ru int t4/1
Current configuration : 74 bytes
switchport mode trunk
Solved! Go to Solution.
Thanks for getting back to me. You're right that it is by default a dot1q trunk allowing all VLANs, therefore it should work for what I want to do.
Port Mode Encapsulation Status Native vlan
Gi3/39 on 802.1q trunking 1
Te4/1 on 802.1q trunking 1
Po1 on 802.1q trunking 50
Po2 on 802.1q trunking 50
Po3 on 802.1q trunking 50
Po4 on 802.1q trunking 50
Po5 on 802.1q trunking 50
Port Vlans allowed on trunk
The problem was that I've always been advised that best practise is to only allow the VLANs that are actually required on a trunk to avoid broadcasting traffic unnecessarily. I worked out what the issue was though, and it was a pretty simple one!
Once I saw that 1-4094 was allowed I tried "switchport trunk allowed vlan remove 700" which worked and left me with 1-699,701-4094.
Then I realised what the problem was trying to use the "add" command when all possible VLANs had already been added. As soon as I got rid of it and used "switchport trunk allowed vlan 700" followed by "switchport trunk allowed vlan add 701" I was back in business.
So it was a very simple issue, but thank you Steve for pointing me in the right direction and confirming that all the VLANs were already allowed!