Trunking Cisco and Extreme Switches

Myrdyn98

I have a Cisco 3550 and an Extreme summit x150. I have them connected by Gigabit fiber. I am trying to trunk them using this line. I have them connected with dot1q and can get both ports up and up but I can't get any packets out of the summit to our network. The switch is using a seperate subnet from the rest of the network but that subnet's default gateway is up already (we are replacing an old switch). Any advice or links to info?

Claymoore

Do you mean trunking or etherchanneling? What the rest of the known universe refers to as 'trunking', Cisco names 'etherchanneling' - combining multiple physical ports into one logical port. Since this is an etherchannel between a Cisco and a non-Cisco device you will need to use LaCP to negotiate the channel. You'll need to add something like this to your Cisco config (an example from one of my SAN switches that etherchannels to an EMC datamover):

interface Port-channel2
description Members g1/41-44
switchport
switchport access vlan 25

interface GigabitEthernet1/44
description DM2 NS80
switchport access vlan 25
channel-group 2 mode passive

The 'channel-group 2 mode passive' is where you define the channel negotiation protocol and how it is negotiated - look at the command options by using the ? and pick the one that works best with your equipment.

I'm only transporting one Vlan, but if you want to carry more than one Vlan across a physical or logical link - what Cisco calls 'trunking' - you'll need to change the port channel to look something like this:

interface Port-channel3
description G4-7 / 25-26 to MDF3
switchport
switchport access vlan 10
switchport trunk encapsulation dot1q
switchport mode trunk

I don't know what the commands would be for the Extreme Summit switch, but hopefully you have a decoder ring somewhere.

Pash

The rest of the known universe uses vlan tagging for vlan trunking it should be mentioned also :P

dtlokee

There could be a number of variables at play here. Take a look at the output of a "show interfaces gigabit x/y trunk" on the Cisco switch and make sure the interface is forming a trunk, and all the VLANs you are trying to send across the trunk are listed under the "VLANs allowed on the trunk" and "VLANs in a spanning tree forwarding state and not pruned" list the VLANs yo uare trying to use. If not you need to look at the configuration of the trunk on both sides to make sure the trunk forms, and if there are VLANs getting pruned off due to VTP pruning then you will need to edit the prune eligabile list on the Cisco switch to prevent it.