Cost communities are a non-transitive value. Which means they can only be used inside an AS or Confederation.
Otherwise, it's just another extended community that can be used to manipulate path selection. If you end up being presented with multiple equal cost paths, the cost value (lowest wins) gives you another mechanism to choose one path over another. Check out: http://cisco.com/en/US/docs/ios/12_0s/feature/guide/s_bgpcc.html HTH, Scott Morris, CCIE4 (R&S/ISP-Dial/Security/Service Provider) #4713, JNCIE-M #153, JNCIS-ER, CISSP, et al. CCSI/JNCI-M/JNCI-ER VP - Technical Training - IPexpert, Inc. IPexpert Sr. Technical Instructor A Cisco Learning Partner - We Accept Learning Credits! [EMAIL PROTECTED] Telephone: +1.810.326.1444 Fax: +1.810.454.0130 http://www.ipexpert.com -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Suresh Mishra Sent: Thursday, February 14, 2008 9:46 AM To: [email protected] Subject: [OSL | CCIE_RS] BGP Cost Community Hello all, I am looking for a document that can help me understand how the cost community is used in BGP decision process. I am looking for examples that can explains the use of community ID and Cost in the BGP decision process. Thanks Suresh Mishra
