All things related to multicast

[Pavlin Radoslavov <>]

>   -- Auto-RP allows you to scope "service areas" within your domain.  At
>      this time, no organization has ever shown the need to do this because
>      the amount of multicast traffic isn't that great.  But the idea is
>      that you might define an RP for "manufacturing" to use the range
>      239.123/16 and another RP for "marketing" to use that same range.
>      You -can not- do this with the Bootstrap router.

Are you saying that you cannot have scope zones with BSR?
The post-RFC2362 BSR spec (draft-ietf-pim-sm-bsr-02.{ps,txt}
available from http://www.icir.org/mjh/pim.html)
allows Admin Scope Zones within the BSR mechanism.

>   -- The BSR uses a hashing process to determine which RP is going to be
>      used.  If you have multiple RPs, it is possible that one group
>      (for example 224.1.1.1) would use one of those RPs, while another
>      group (224.1.1.2) would use a different RP.  The idea was that if
>      your network had lots of multicast traffic, you wouldn't want to
>      overload the RP with all of that traffic, but distribute it.
>      However:
>       -- getting the hash right on all routers and between vendors was
>          a problem.

The hash is independent from the method used to distribute the RP
set, so it has nothing to do with the BSR.

>       -- there is no way to scope sub-domain service areas.  (I should

Not true (see above).

>       -- With Auto-RP the network manager defines which RP is responsible
>          for which group.  There is no "magic" distribution of groups
>          among multiple RPs.

There is nothing to prevent you from doing the same with the BSR.

IMO, static RP and BSR are the two mechanisms that give you the
spectrum of what you need (SSM is orthogonal; Anycast-RP is
complementary):

 * The static RP is very simple and easy to understand, but lacks
   flexibility if an RP fails (the Anycast-RP is a work-around for
   that). And, of course, you need to configure things manually.

 * The BSR can deal with RP failures, and can work in a
   plug-and-play fashion. Of course, you need to know how it works
   to have it on your side and do some specific tasks.

Things like mixture of sparse-dense mode just add too much
complexity to the picture.

Pavlin