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 Mailto: [email protected] Telephone: +1.810.326.1444 Live Assistance, Please visit: www.ipexpert.com/chat eFax: +1.810.454.0130 IPexpert is a premier provider of Self-Study Workbooks, Video on Demand, Audio Tools, Online Hardware Rental and Classroom Training for the Cisco CCIE (R&S, Voice, Security & Service Provider) certification(s) with training locations throughout the United States, Europe, South Asia and Australia. Be sure to visit our online communities at www.ipexpert.com/communities and our public website at www.ipexpert.com -----Original Message----- From: "LUCHO ORTEGA" <[email protected]> Date: Wed, 12 May 2010 00:51:31 To: ccie_rs<[email protected]> Subject: [OSL | CCIE_RS] Backbonefast on NM16-SW - Dynamips/GNS3 _______________________________________________ For more information regarding industry leading CCIE Lab training, please visit www.ipexpert.com _______________________________________________ For more information regarding industry leading CCIE Lab training, please visit www.ipexpert.com
