Re: BSR Configuration

From: Ben (bmunyao@gmail.com)
Date: Sat Jul 07 2007 - 13:13:19 ART


Hi Wim

Rack1R4#
*Mar 1 01:43:06.671: PIM-BSR(0): bootstrap on non-RPF path Serial1/1
Rack1R4#
*Mar 1 01:43:16.715: PIM-BSR(0): bootstrap on non-RPF path Serial1/0
Rack1R4#

This debug indicated that the multicast path does not coincide with the
unicast path
 The BSR is sending multicast adverts of RP-set over the path defined by
PIM. The router receiving this multicast, on checking its unicast routing
table , finds that the unicast path to the BSR loopback address is
different, hence the RPF failure.

Solutions:

1. You can tune IGP to ensure the two paths are the same.
     or
2. You can use the "ip mroute" command on the router receiving these
multicasts, defining the next hop to the BSR via the multicast path

For example, in the diagram below, the R1 loopback (150.4.1.1) is the BSR
address, and pim SM is enabled on the lower path interfaces passing thro R5
(the scenic route). Your IGP however will most likely pick the the upper
path to get from R4 to R1 (150.4.1.1).

          ---------------------------------
          | |
          | |
(BSR)R1----------------------------R4
          | pim | pim
          | |
          -------------R5---------------
                 pim pim

In this case, you will get the RPF failure unless one of the above solutions
are used.

HTH

Ben

On 7/5/07, Bob Sinclair <bob@bobsinclair.net> wrote:
>
> wim.depauw@getronics.com wrote:
> > Hi,
> >
> > I'm wrestling with a simple BSR configuration :
> > I created the following network
> >
> > R1----FR-----R4----HDLC-----R5----ETH----E2
> > |--------------------FR------------------ |
> >
> >
> If your BSR is on a spoke, then try enabling nbma-mode on the hub. In
> my experience, the hub will not resend the BSR messages on an incoming
> interface, unless you use the nbma-mode enhancement.
>
> HtH,
>
> --
>
>
> Bob Sinclair CCIE 10427 CCSI 30427
> www.netmasterclass.net
>
> _______________________________________________________________________
> Subscription information may be found at:
> http://www.groupstudy.com/list/CCIELab.html



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