Adding a 3548XL switch to environment running MST Protocol

[pmajumder]

Hi,

I have a LAN environment where the spanning-tree mode is MST. This LAN is made of Cisco 6509's and Cisco 4506's - where the design is fully redundant .

I now need to add a Cisco 3548XL to this topology, and this is where the issue arises since the 3548 does not understand MST, and as such I don't want to create any STP issues.

What is the best way to go about implementing this?

Should I create a separate VTP domain and have a trunk connection to the existing LAN?

OR

Should I place it on the same VTP domain and a regular trunk connection?

OR

Should it be a separate LAN, i.e. a routed connection to existing LAN?

OR ?????

Please, any ideas with Pro's and Con's would be very helpful.

Thank you

Pradeep

[carenas123]

You can use PVST+ which can communicate with MST. But please note that, the PVST+ connection from 3548xl switch to the MST region MUST be through 802.1q trunks. Through tunneling concept, PVST+ and MST are interoperable.

[pmajumder]

Thank you for the feedback. I found out that the only drawback to introducing a PVST+ switch is an increase in the convergence time. I was able to mitigate this by disabling STP on the Cat3548xl, since it did not have any redundant links to the rest of the network.