Re: mixed ISL & dot1Q trunking for a single VLAN

mflanigan · ‎10-30-2001

Has anyone tried trunking a single VLAN with a mix of ISL & dot1Q trunks? I have a customer with 1900's, 3500's, and 3Com switches. The 3Com's only do dot1Q, the 1900's only do ISL. Since trunking is specified on a per port basis, I would think it might be possible to propagate a single VLAN over the whole environment, depending on how much frame re-writing the 3500 does. I actually set this up inadvertently in an all-3500 environment, and it seemed to be working. The 3524-PWRs were doing dot1Q trunking to the IP phones, and ISL was running on the GBIC uplinks to a 3548. This was only in place for a brief period, though, and I am wondering about broadcast/multicast and STP issues.

zoushan · ‎10-30-2001

I hope this can help you :I have a catalyst 2948G and a catalyst 2924xl and many catalyst 1924. 2924 uplink to 2948G, 1924 uplink to 2924. 2948G and 2924 uplink is 802.1q trunk. 1924 and 2924 uplink is isl trunk. It works well.

mflanigan · ‎10-31-2001

Thanks, that's what I was expecting, but I wasn't sure

duani · ‎11-05-2001

Hello !

Is there any special configuration when I am

working with 3com

duani · ‎11-05-2001

Hello !

Is there any special configuration when I am

working with 3com

mflanigan · ‎11-05-2001

Apart from specifying 802.1q on any 3Com connections, I don't believe so.

duani · ‎11-06-2001

I did it

The problem was with vlan number 1

That was discard by the 3com It was the native vlan

so I just change the native vlan to a number that Is not in use and evry thing is o.k

802.1q was configurd also before