802.1q trunk from Cisco 3550 to Extreme Alpine

Hi,

I am trying to setup a VLAN trunk between a Cisco Catalyst 3550 and an
Extreme Alpine switch but have not been able to get it working.

I d/l'ed a config from a Catalyst 2950 (which I have been able to get
trunking working on no problem simply by using 'switchport mode trunk') to
the 3550 but then realised that it would need more configuring due to the
3550 being able to do ISL trunks.

I dont have access to the config currently so cant paste in full but
basically I modified the config by issuing the following commands on the
g0/1 interface:

switchport trunk encapsulation dot1q
switchport mode trunk

However this does not seem to work. Untagged traffic is fine but I can not
ping the IP on the Cisco vlan100 which is the VLAN I am trying to trunk
across the link.

I think my Alpine config is fine because it is configured the same way for
the trunk with the 2950 which works OK. It seems as if the Cisco is trying
to use an ISL trunk even though I have forced it to 'dot1q' ?

Any info would be greatly appreciated.

Cheers, Dan

 

Have you tried fixing the Extreme to 802.1q as well? If I recall correctly
Extreme also understands ISL.

Erik

 

Make sure that native VLANs match

--l0stbyte

 

Have you created the VLAN 100 in the Cisco's VLAN database? If not, it
will probably not pass the trunk.

switchport trunk encaps dot1q
switchport mode trunk
switchport nonegotiate

Strongly recommended, if you ask me