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Spanning Tree Question

Hi all,

I've recently read that, unlike Cisco, BPDUs are not sent on the native/untagged - or any other - vlan.

Questions:

1. Is this really true?
2. If so, what effect does this have on spanning tree's ability to correctly detect loops?
3. What considerations are there on a medium sized HP Procurve network (20 switches, with separate access + distribution layers) to ensure that spanning tree correctly detects loops?

Basically, I'm looking for a decent explanation on how this difference between Cisco's and HP's implementation of spanning tree, and how I can prevent loops in an HP environment.

(this isn't academic, a recent loop in the network took out all switches and all vlans on the entire network)

Cheers

convergint

On Procurve switches the BPDU is turned off by default and you must enable it to protect your network from loops.

The syntax from the CLI is:

spanning-tree all bpdu-protection

This basically enables the bpdu protection on every port, afterwards you should disable it on the uplink ports:

no spanning-tree {port} bpdu-protection

This blog has more detailed information: http://evilrouters.net/2009/03/11/bpdu-protection-on-hp-procurve-switches/

You can also download this HP whitepaper which discusses the differences in much finer detail: http://www.techdata.ca/techsolutions/networking/whitepapers/Feb10/HP%20Procurve%20Migrating%20from%20Cisco%20to%20ProCurve%20Networks.pdf

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TimotiSt

See attached HP interop guide for detailed explanation and practical examples, STP starts on page 21.

Tamas
procurve-cisco-interop.pdf