Hello Marc, The purpose of Multicast BGP in this instance was to solve the RPF failure that was bound to occur because PIM was enabled on all of the interfaces leading to the other domain. If you notice earlier in the lab BGP was supposed to prefer the path that is not PIM enabled thus resulting in an RPF failure. You may want to go back and check if you are prefering the correct paths. I hope this helps. Feel free to let me know I'm wrong :)
Sent from my Verizon Wireless Phone ----- Reply message ----- From: "marc abel" <[email protected]> Date: Wed, Aug 24, 2011 5:49 pm Subject: [OSL | CCIE_RS] Multcast BGP - related to lab Vol3 lab 5 config task 4.4 To: <[email protected]> I am still pretty confused about using multicast BGP and would appreciate any explanation about it including it's purpose and how it works. Specific to this lab and task there is this requirement. Configure inter-domain multicast routing in AS17, AS218, and AS469 such that all multicast routers can ping group joined by R9, as well as group 239.0.0.21 joined by BB1. You are required to configure BGP for this task. So I have setup multcast in those domains, filtering my RP's between the AS's. I have setup MSDP between the 3 RP's. Now I can ping those groups from everywhere. I have not setup multicast BGP yet. So in this scenario what is the purpose of MBGP? Is is just because they said so? Or is it actually supposed to be doing something? Does MBGP actually transport the multicast? or does it just transport the RP information? Or maybe it only makes interfaces pass the RPF check? Really confused. Thank you. _______________________________________________ For more information regarding industry leading CCIE Lab training, please visit www.ipexpert.com Are you a CCNP or CCIE and looking for a job? Check out www.PlatinumPlacement.com _______________________________________________ For more information regarding industry leading CCIE Lab training, please visit www.ipexpert.com Are you a CCNP or CCIE and looking for a job? Check out www.PlatinumPlacement.com
