[f-nsp] FESX spanning-tree path cost success?

[Christian MacNevin]

By the way, the way I dealt with this in the conference I was just  
working on was to find the link between the two candidate roots
and jump that cost.

So for 10Gig links with a default cost of 2 and 1Gig with a default of  
4, I raised the interlink between the two roots to 3.
This worked cause we had a weird set of rings as the uplinks were  
costing us a grand a pop :S

root--------3---------root_standby
|						|
|						|
2						2
|						|
|						|
aggregate----2----aggregate
|						|
|						|
4						4
|		 				|
access-4-access-4-access


The idea was that that middle access switch (and everything else)  
should use the left path to the root unless there was a down link
as we wanted to be able to SPAN everything from that one root switch  
and wanted a more deterministic approach.

I'm guessing you don't have quite such an easy setup. What are you  
guys doing there? qinq style pseudo-vpn layer 2 stuff?




On Sep 9, 2008, at 5:40 AM, Jonathan Brashear wrote:

Nice job sending that to the list. :p


Network Engineer
> 214-981-1954 (office)
> 214-642-4075 (cell)
> jbrashear at hq.speakeasy.net
http://www.speakeasy.net
-----Original Message-----
From: Christian MacNevin [mailto:christian.macnevin at gmail.com]
Sent: Monday, September 08, 2008 3:12 PM
To: Jonathan Brashear
Cc: foundry-nsp at puck.nether.net
Subject: Re: [f-nsp] FESX spanning-tree path cost success?

It's your small knob. Get that fixed first.


On Sep 8, 2008, at 5:58 AM, Jonathan Brashear wrote:

Our DC has had intermittent issues over the past year with spanning-
tree loops with customers who have multiple uplinks to our switch
fabric.  We've explored a few different options with limited to no
success(such as bpdu guard, stp-protect, etc.), but currently we're
considering setting manual path costs on ports as a way to help avoid
the loops & subsequent cpu spikes we've dealt with.  Has anyone
deployed manual path costs for customers with multiple uplinks(either
to the same switch or multiple switches), and if so what success/
problems have you had with its implementation?  I'd prefer the info be
from the FastIron environment, but any Foundry-related discussion
would be appreciated.

Network Engineer
> 214-981-1954 (office)
> 214-642-4075 (cell)
> jbrashear at hq.speakeasy.net
http://www.speakeasy.net
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