Re: [OSL | CCIE_RS] Backbonefast on NM16-SW - Dynamips/GNS3

[LUCHO ORTEGA]

Hi Joe,

To simulate the link going down I was shutting down on A the designated port toward B instead of shutting down the root port on B.

It had become so tough getting to see the frames that A & B would exchange (RLQ) that at some moment I thought this RLQ frame was actually God's particle.

Well, after this minor change in the approach I was able to capture these 2 frames exchanged by A & C. Nah! It is not God's particle.

What is good is that I now understand how and under what circumstances Backbonefast works.

BTW, I was testing PVST mode which is all that the NM16-SW offers.

Thanks,

------ Original Message ------
Received: 02:07 AM EDT, 05/12/2010
From: "Joe Astorino" <jastor...@ipexpert.com>
To: "LUCHO ORTEGA" <lucho.ort...@usa.net>,ccie_rs-boun...@onlinestudylist.com,"CCIE OSL" <ccie_rs@onlinestudylist.com>
Subject: Re: [OSL | CCIE_RS] Backbonefast on NM16-SW - Dynamips/GNS3

What STP mode are you running? Try debug spanning-tree events on C during the link failure. Without BB fast it may change port state to DP immediately, but you should see it wait 20 second in blocking, then 2x forward-delay for listening/learning. You can see these changes in the debug.

What you are describing (immediate switch of C to DP) is precisely what BB fast should do. BB fast really gives you a backup designated port on the segment. I am not positive if NM has something to do with it but when you do get some rack time I encourage you to try it.

Also, check out the blog on STP direct vs indirect link failures I did a while ago -- I think it may shed some light along with Cisco's whitepaper on Uplinkfast/Backbonefast


Sent from my Verizon Wireless BlackBerry

Regards,

Joe Astorino - CCIE #24347
Sr. Technical Instructor - IPexpert
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-----Original Message-----
From: "LUCHO ORTEGA" <lucho.ort...@usa.net>
Date: Wed, 12 May 2010 00:51:31
To: ccie_rs<ccie_rs@onlinestudylist.com>
Subject: [OSL | CCIE_RS] Backbonefast on NM16-SW - Dynamips/GNS3

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