[j-nsp] Tricks for killing L2 loops in VPLS and STP "BPDU-less" situations?

[Jensen Tyler]

Quick google for "VPLS Multihoming" found me this:

http://www.juniper.net/techpubs/en_US/junos9.6/information-products/topic-collections/feature-guide/vpls-multihoming-bgp-signaling-solutions.html

Jensen Tyler
Sr Engineering Manager
Fiberutilities Group, LLC

-----Original Message-----
From: juniper-nsp-bounces at puck.nether.net [mailto:juniper-nsp-bounces at puck.nether.net] On Behalf Of Clarke Morledge
Sent: Friday, August 17, 2012 10:09 AM
To: juniper-nsp at puck.nether.net
Subject: [j-nsp] Tricks for killing L2 loops in VPLS and STP "BPDU-less" situations?

We have had the unfortunate experience of having users plug in small mini-switches into our network that have the capability of filtering out
(by-default) BPDUs while allowing other traffic through.  The nightmare situation is when a user plugs in such a switch accidentally into two of our EX switches.  Traffic will loop through the miscreant switch between the two EXs and without BPDUs it just looks like MAC addresses keep moving between the real source and the two EXs.

In an MX environment running VPLS, this problem can happen easily as there are no BPDUs even to protect against loops in VPLS, particularly when your VPLS domain ties into a Spanning Tree domain downstream where your potential miscreant switch may appear.

I am curious to know if anyone has come up with strategies to kill these loops for EXs running Spanning Tree and/or MXs running VPLS. 
Rate-limiting may help, but it doesn't kill loops completely.  I am looking for ways to detect lots of MAC address moves (without polling for
them) and blocking those interfaces involved when those MAC moves exceed a certain threshold via some trigger mechanism.

Assume Junos 10.4R10 or more recent.

Clarke Morledge
College of William and Mary
Information Technology - Network Engineering Jones Hall (Room 18) Williamsburg VA 23187 _______________________________________________
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