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New Member

create a dot1q trunk between 4500X and ME3600X

Hi There,

today during an initial configuration of a network i came to a simple issue. supposed to be simple :-)

When i set up a trunk between ME3600X and 4500X i failed.

ME is not supporting "desirable" and so in need to set up the trunk in mode "on" there.

On the other side desirable is supported, however i were not able to establish a working trunk.

When i initally set up the trunk I configured in desirable mode on 4500X --> failed

When i set trunking to on the devices tells me that this port is trunking, however in fact the trunk is still not working.

After this i changed config back to desirable and the 4500X shows me the port "trunking" but in fact trunking is still not working.

config is as followed:

on ME3600X:

int gi0/20

switchport trunk allowed vlan 25-27,30,31,40

switchport mode trunk

on 4500X

int te1/32

switchport trunk allowed vlan 25-27,30,31,40

switchport mode dynamic desirable

Has anyone an idea what could be wrong there. The link status is up / up

Is there some sort of best practise trunk configuration for my setup available?

Thanks for your assistance in advance

Everyone's tags (4)
3 REPLIES

create a dot1q trunk between 4500X and ME3600X

You said that the ME doesn't support the 'switchport mode dynamic desirable' command.

What would happen if on the 4500X you configured the following

int te1/32

switch mode trunk

swich trunk allowed vlan 25-27,30,31,40

Basically, 'dynamic desirable' is using DTP . It's basically saying, hey I want to negoitate a trunk with you, and if it can't it reverts to an access port. But 'dynamic desirable and mode trunk' should be availabel to form a trunk...

New Member

create a dot1q trunk between 4500X and ME3600X

If i do a switchport mode trunk the status chages to "trunking", however in fact the trunk is still not working.

And the cracy thing is when i switch back from "switchport mode trunk" to "switchport mode dynamic desirable" trunk remains up, but is still not working.

Re: create a dot1q trunk between 4500X and ME3600X

Hi.
Can you post a show interface trunk of both switch?
Thanks

Regards
Carlo

Sent from Cisco Technical Support iPhone App

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