[c-nsp] Deploying MSTP

Steve Dodd sdodd at syringanetworks.net
Wed Dec 28 11:14:07 EST 2011

-----Original Message-----
From: cisco-nsp-bounces at puck.nether.net [mailto:cisco-nsp-bounces at puck.nether.net] On Behalf Of Chuck Church
Sent: Wednesday, December 28, 2011 7:02 AM
To: 'Frédéric Loui'; 'Jay Nakamura'
Cc: 'cisco-nsp'
Subject: Re: [c-nsp] Deploying MSTP

Yep, definitely important to verify what VLANs are mapped to the instances.  The Nexus for example reserves some VLANs that aren't obvious, so when you map them, they end up back in instance 0 with no warning.  IOS didn't reserve those, so both my instance 0 and the one with high-numbered VLANs didn't match, so I had all kinds of problems till we discovered that.  There is a checksum that you can get it to display that should match between all connected devices.  Can't remember the command, but it worked well.


show spanning-tree mst configuration digest

will show you the hash and should match on all devices in the MST region.


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