All things related to multicast

[Mike McBride <>]

If your customers maintain their own RP, you can peer directly with them
using one of your Anycast RPs. RPF works when receiving your SAs if they
default peer to you (or single peer) and RPF passes on receiving customer
SAs because you would be peering with their originating RP. No mesh
groups needed aside from your Anycast RP mesh. I believe most
implementations will skip peer rpf check when:

MSDP peer is originating RP
MSDP peer is default peer (or single peer)
MSDP peer is in same mesh group

You don't need to run the msdp peering between your border routers unless
that's what you want. Some providers find more flexibility in choosing
routers further into your AS for the MSDP peerings. Again, a common
deployment is several Anycast RPs in the providers AS, all being in the
same msdp mesh group. All routers within the providers AS statically
point to the Anycast RP address. Anycast RPs peer with customer RPs. This
is in addition to customers chosing not to run their own RP, no msdp, and
instead use the provider RP.

You should use mesh group where they make sense, but running a mesh group
to each customer seems a bit burdensome. I think mesh groups should only
be used intradomain.

mike

On Thu, 4 Apr 2002, Michael Hare wrote:

> Folks-
>
> I work for WiscNet (statewide educational network) up in Wisconsin.  We're
> starting to offer multicast services to any of our 500+ members who request
> it.  We currently run a sparse-mode WAN network, use anycast RP, and have
> two MSDP peering points with the outside world.  I'm struggling with how to
> exchange multicast with those members.  How are other organizations
> operating?
>
> We're currently letting each member use our RP.   We use OSPF pretty much
> exclusively as our IGP (BGP with very few members).  Seems to work OK.  We
> thought this would be the easiest to troubleshoot (for us).  Caveats
> include unnecessary WAN link utilization until SPT's are built for traffic
> that is really only supposed to stay inside the campus..  I don't yet have
> a feel for how thats really happening.
>
> I've also thought up of a second approach.  Each site could have their own
> RP and we'd MSDP peer with them.  From what I've read, you can only run
> MSDP with a non BGP neighbor if you're peering with a single MSDP peer or a
> mesh group..  So I'm assuming our customers could run an MSDP mesh with our
> border routers, and then I'd have to create separate mesh groups on each of
> our border routers for each customer.  This sounds a lot more complicated
> but seems to avoid unnecessary multicast traffic on our WAN links, and
> introduces lots of MSDP traffic in its place
>
> Any comments would be greatly appreciated.
>
> Thanks-
> -Michael
>
> /\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\
>
> Michael Hare
> UW-Madison Network Engineering
> WiscNet Network Engineering
> My phone: 608-262-5236
> 24-Hour NOC: 608-263-4188
> WiscNet: 608-265-6761
>
>