From: Brian McGahan (bmcgahan@internetworkexpert.com)
Date: Wed May 17 2006 - 20:40:24 ART
Tony,
Try not to get into general rules and instead try to solve the
scenario based specifically on what the question is asking. In some
circumstances you will need static mrouting, in some you will not. Just
be aware of the fact of how to determine if it is necessary, such as
"show ip mroute count", "debug ip mpacket", etc.
HTH,
Brian McGahan, CCIE #8593
bmcgahan@internetworkexpert.com
Internetwork Expert, Inc.
http://www.InternetworkExpert.com
Toll Free: 877-224-8987 x 705
Outside US: 775-826-4344 x 705
24/7 Support: http://forum.internetworkexpert.com
Live Chat: http://www.internetworkexpert.com/chat/
> -----Original Message-----
> From: Tony Paterra [mailto:apaterra@gmail.com]
> Sent: Wednesday, May 17, 2006 6:15 PM
> To: Brian McGahan
> Cc: Cisco certification
> Subject: Re: IEWB Vol. 1 Lab 1 Multicast RPF checks against the RP...
>
> Brian,
> Thanks for the clarification. As a best practice is it safe to go an
> put static default mroutes on multicast routers that appear on the
> edge of the network (but probably have a unicast routing table that
> will cause RPF checks)?
>
> Adios,
> Tony
>
>
> On May 16, 2006, at 10:07 AM, Brian McGahan wrote:
>
> >> interface? If R2 is the mapping agent, does it matter that it
can't
> >> pass around the multicast address for cisco-rp-discovery?
> >
> > Yes it does matter. Since the candidate RP sends its
> > announcements as a multicast to the mapping agent these must pass
> > RPF as
> > they are forwarded. Likewise the mapping agents advertisements to
the
> > rest of the PIM neighbors are multicast and must also pass RPF. An
> > alternative would be to use BSR because it uses a combination of
> > unicast
> > and hop-by-hop communication.
> >
> >
> > HTH,
> >
> > Brian McGahan, CCIE #8593
> > bmcgahan@internetworkexpert.com
> >
> > Internetwork Expert, Inc.
> > http://www.InternetworkExpert.com
> > Toll Free: 877-224-8987 x 705
> > Outside US: 775-826-4344 x 705
> > 24/7 Support: http://forum.internetworkexpert.com
> > Live Chat: http://www.internetworkexpert.com/chat/
> >
> >
> >> -----Original Message-----
> >> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On
Behalf
> > Of
> >> Tony Paterra
> >> Sent: Monday, May 15, 2006 11:10 PM
> >> To: Cisco certification
> >> Subject: IEWB Vol. 1 Lab 1 Multicast RPF checks against the RP...
> >>
> >> I was going through the multicast portion of the first lab and
(being
> >> a little fresh to mcast) have noticed some unexpected behaviors.
R3
> >> is supposed to announce it's loopback as the RP for all multicast
> >> groups and R2 is supposed to announce it's loopback as the mapping
> >> agent. I understand these pieces, the real question... Is that
I'm
> >> running debugs and seeing RPF check failures on R5 for (150.1.2.2,
> >> 224.0.1.40) because of the unicast routing table.
> >>
> >> Is this the way this is supposed to operate? Are there any other
> >> ways
> >> around this outside of static mroutes or enabling multicast on the
> >> necessary interfaces to reach R5 on the proper (ethernet0/0)
> >> interface? If R2 is the mapping agent, does it matter that it
can't
> >> pass around the multicast address for cisco-rp-discovery?
> >>
> >> Thanks in advance,
> >> --
> >> Tony Paterra
> >> apaterra@gmail.com
> >>
> >>
> >
This archive was generated by hypermail 2.1.4 : Thu Jun 01 2006 - 06:33:21 ART