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New Member

Trunk port


The trunk port is not coming up after setting up the trunk using the "set trunk command" in cat 6509 ( module 2).any suggestion would be appreciated.

Cisco Employee

Re: Trunk port

Make sure that the other end is also configured for a trunk. If you set both sides to on with the same trunk encapsulations and it still does work then I would check the fiber . Hope this helps,


Cisco Employee

Re: Trunk port

New Member

Re: Trunk port

1. Make sure you configure the exact same type of trunking protocol on both sides of your trunk link. If you specify ISL trunking on one side it must be same on the other. If however, you specify 802.1q the same applies.

2. Critical! - Make sure you have the ports set to the same Native VLAN on both sides before you set up the trunk. What happens is that all other (non-native) VLANs you trunk over the link are tagged. Those in the native VLAN are not tagged in the trunk link. If it is not the same native on both sides of the link then they will be completely foreign & invisible to each other.

Good luck.