Subject: Re: Multicast

From: Gunnar Lindberg <[email-masked]>
Date: Thu, 8 Mar 2001 09:12:57 +0100

Please explain what's wrong with my take on multicast scalability:

Every time a new sender shows up, the entire multicast core (RPs,
right now those running MSDP in the default free zone) has to be
informed. To "show up", the host just starts sending data.

Every time a new receiver shows up, its nearest RP has to initiate
a data distribution path (tree) torwards the sender(s). This is
likely to involve at least some of the core routers.

Scalability problems:

    1)	An indivivual sender - host, my Linux PC - affects routing
	information in the entire router core. Just send data.
	There are a few hosts on the Internet.

    2)	As if his wasn't enough, consider the potential for DoS-
	attacks. The recent Ramen worm was the first(?) example;
	who can claim it was the last?

Assume technology evolves fast enough to solve 1). We still have 2).

My claim is that it doesn't scale to allow individual hosts to affect
the Interet core routing system. What do I miss?

	Gunnar Lindberg

---

From: Masataka Ohta <[email-masked]>
Date: Sat, 10 Mar 2001 00:54:29 +0859 ()

Gunnar;

> informed. To "show up", the host just starts sending data.

You are wrong to say "multicast scalability" instead of "MSDP
scalability".

> Assume technology evolves fast enough to solve 1).

No, it does not.

> the Interet core routing system. What do I miss?

Then entire multicast (actually MSDP) core has nothing to do with
the Internet core routing system.

							Masataka Ohta