stp, hsrp best practices

[brad182]

Hi, couple of questions here...
1. What is better to use when configuring preferred stp pathways, path cost or port priority? Seeing as the path cost is dynamiclly determined by the media speed, and port priority starts with a default of 128, I was planning on defining preffered routes via the port priority??

2. Are there any hidden traps when using stp with hsrp, i.e. I will have 2 3550 L3 switches at the core of the network using hsrp for first hop redundancy, these switches will have several vlans configured as virtual interfaces.
I beleive the 3550s will still participate in stp as they are still primarly switches. Hence setting 3550a as stp root primary and 3550b as stp root secondary.

thanks
brad

 

[baddos]

HSRP and Spanning tree don't mess with each other. In fact they work well together.

To influence the spanning tree algorithm, you can use the "spanning-tree cost" cost command on each interface. With this, you can artificially inflate or deflate the cost of the interface to change from forwarding to blocking or vs.

 

[krr]

You have to watch out for the spanning tree forwarding delay.

See

http://www.cisco.com/warp/public/cc/so/cuso/epso/entdes/hsrp_wp.pdf

and especially

http://www.cisco.com/warp/public/619/8.pdf

to avoid problems.

*Rob