pim nbma has nothing to do with RPF . only three parameters matters to RPF , igp unicast table , MBGP , mroutes.
" pim nbma " is used for disable split horizon , similar to any distance vector split horizon rule. By default a router includes the interface S 0/0 in OIL , after enabling pim nbma it inclued based on neighbors ip's on that interface. you will see after S0/0 , an ip address of remote dlci appear in oil . After enabling nbma , i always reload the router router :-) . The only thing to worry about here is spoke should not become ASSERT winner on a hub and spoke topology , as now hub prunes back and remaining spokes which are only connected to hub will not get the feed. further " pim nbma " does not work with dense mode... On Thu, Mar 21, 2013 at 8:02 AM, Bob McCouch <[email protected]> wrote: > Hey Michael, > > I'm pretty certain you won't get a PIM adjacency up over a frame PVC that > does not have pseudo-broadcast enabled. PIM uses 224.0.0.13 for neighbor > discovery. And the multicast packets that PIM is routing most definitely > need a broadcast-enabled frame PVC. > > The 'ip pim nbma-mode' is not related to whether PIM uses link-local > multicast for neighbor discovery, rather it is used to deal with potential > RPF issues in a frame-relay hub and spoke network. If the hub receives a > multicast packet from a spoke off of the frame-relay link on Serial1/0, for > example, it would not be able to forward that same packet back out to > another spoke neighbor off the same interface as the interface the packet > was received on (the RPF interface) cannot be included in the OIL for the > group (as that would indicate an automatic RPF violation). > > 'ip pim nbma-mode' simply allows the router to include the actual PIM > neighbor ID rather than the interface in the OIL so that the router can > "hairpin" the multicast packet and send it back out to spokes other than > the one it was received by. > > Can you get PIM and multicast across a non-broadcast frame-relay link? Sure > -- that's what tunnels are for ;-) > > Good luck on your lab! > > > On Thu, Mar 21, 2013 at 12:03 AM, Michael Davis - Webquor < > [email protected]> wrote: > > > Hi everyone – I am working on multicast which is my biggest weakness > > leading up to the lab next week. I am trying to get a PIM adjacency > over a > > non broadcast frame-relay connection. It is not coming up. Can someone > > please explain if it is possible and why the command "ip pim nbma-mode" > is > > necessary on non-broadcast networks? The command doesn't seem to do > > anything to be honest. I suppose the big question is can I establish a > PIM > > adjacency over a frame-relay connection where no broadcast capability is > > enabled? > > > > _______________________________________________ > > 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 > > > > http://onlinestudylist.com/mailman/listinfo/ccie_rs > > > _______________________________________________ > 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 > > http://onlinestudylist.com/mailman/listinfo/ccie_rs > _______________________________________________ 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 http://onlinestudylist.com/mailman/listinfo/ccie_rs
