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MST(STP) help needed....weighting links, etc..

I need some help doing some manual tweaking with MST(STP). Here is the scenario.

We have two load balancers with two uplinks (gigabit) going to two 6509s (one link each for a mesh configuration). There is a primary and a secondary load balancer.The second only takes over if the first box dies.

The load balancers can run MST but it has been recommended by the vendor not to run MST/STP so the load balancers are only doing passthru of BPDUs and NOT participating in the MST/STP algorithm. I need to know what the commands are to tweak the weighted values to make the load balancers fail in this particular order:

Primary LB - uplink #1 . then

Primary LB - upnlink #2 which goes to 6509#2, then

Secondary LB - uplink #1 which goes to 6509#1, then

Secondary LB - uplink #2 which goes to 6509#2.

Can someone give some advice please and perhaps the commands to make the Cisco weight out the links correctly so that MST/STP fails from link to link in the above listed order? Any information is highly appreciated.

Thank you,

  • LAN Switching and Routing

Re: MST(STP) help needed....weighting links, etc..

Hi Jake,

I'm not sure yet about the design. Here are some few additional questions:

-Is there a L2 link between the cat6ks, beside the connection through the load balancers?

-Is the secondary load balancer (let's call it LB2) forwarding traffic between its uplinks when it is in standby mode.

-Are you attempting to distribute traffic on several vlans, in order to use several uplinks at the same time, or are you ok with just one uplink being active at a given time for all the L2 traffic.

-Also, something stupid, how do you switch over from LB1 to LB2 if LB1 loses both its uplinks 1 and 2 to the cat6k?

A priori, I would say that making cat6k1 the root should be enough.