Hello Marc, I meant to say PIM "was not" supposed to be enabled on the interfaces leading out of the AS's. The only interface that PIM was to be enabled on is an interface which was not preferred in BGP. Multicast BGP is used for RPF checks and also using it will not effect the IPV4 routing. Let me know if I'm wrong.
> Date: Thu, 25 Aug 2011 11:39:50 -0500 > Subject: Re: [OSL | CCIE_RS] Multcast BGP - related to lab Vol3 lab 5 config > task 4.4 > From: [email protected] > To: [email protected] > CC: [email protected] > > Thanks for replying. I did some more reading and I now understand MBGP > is just for RPF checks. I will say this is a topic ripe for blog post > (hint hint Marko). I didn't see much out there on the topic from any > of the vendors. > > I have moved on to the next lab already but I went back and looked at > the guide. I don't understand which interface isn't supposed to be PIM > enabled. I enabled it on all interfaces in the listed ASes, maybe that > is where I went wrong. > > On Thu, Aug 25, 2011 at 11:04 AM, [email protected] > <[email protected]> wrote: > > 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
