All things related to multicast

[Hoerdt Mickael <>]

Hello,

The last 5 years in the multicast routing community have seen a lots of
change in the way that we can interpret how we can have multicasting as
a standard service for the Internet users : much more bandwidth is
available,
much more processing power, new multicast services models, new addressing
and routing solutions and new implementations.

What I would try do here is to now sum up the progress accomplished with
you,
to have an idea where we stand today with layer 3 multicasting to have a
nice view of
the tradeoffs given by each solutions.

For me, two technical  solutions emerged : PIM-SSM + MLDv2/IGMP3 and
PIM-RP-embedded+MLDv1/IGMPv2. The first one is the implementation of the
SSM model the second one implements the ASM model (which is an overset
of SSM).

So here is the thing that I would like that we fill up together, I
already started as you
can see:

PIM-SSM, MLDv2/IGMPv3 :

Pro :
. Works with IPv4/IPv6
. A source can enforce its channel.
. Don't need modifications to PIM, only edges routers have to be modified.
. Control plane and data plane are totally disjoint
....

Con:
. All the hosts need to implements MLDv2/IGMPv3
. Need to maintain a (S,G) per sources in the group.
. To to discover new sources can takes a long time
....

Missing:
. How to efficiently do dynamic source discovery.
. S from (S,G) is a central point of failure.
....

PIM-RP-embedded, MLDv1/IGMPv2:

Pro:
. Very simple way to do inter-domain ASM, by elegantly coupling
adressing and
   routing.
. You don't have to modify the hosts.
. In-band multicast source discovery per group.
. Could maintains one (*,G) per group no matter how many sources you have.
....

Con:
. Only works with IPv6.
. Need alls the routers to be modified.
. PIM-SM Register encapsulation is ugly.
. Could maintains one (*,G) per group and one (S,G) per source in the
group is the
  DRs switched to the SPT.
....

Missing:
. How do I manage my RP ?
. where to put the RP ?
. How do I control the access to my RP ?
. How to have well known multicast addresses for inter-domain ?
....


Hoerdt Mickaël