Subject: Re: packet loss between mbone2.UU.Net & SanFrancisco.mci.net

From: [email-masked] (Tim Dorcey)
Date: Tue, 11 Feb 1997 16:47:28 -0800

At 11:12 AM 2/11/97, [email-masked] wrote:
>|> "Dorian R. Kim" <[email-masked]> wrote:
>|>         4) A business model that ISPs can use. Billing by the size of the
>|> pipe doesn't cut it.
>
>"Doesn't cut it" *compared to what*?
>
>"What are the real marginal costs associated with usage?"  There is
>no moral issue involved in making people pay for "actual usage" if
>it is cheaper to provide better service without such billing.
>[I guess this is why economists are rarely politicians  ;-)  ].

I think the point is not "pipe size" versus "actual usage," but "pipe"
versus "tree."  If I accept a multicast packet into my network, I may need
to carry more than one copy out of my network, which would seem to have
implications for capacity planning.

If the Internet were fully multicast capable, then each person on a 28.8
dial-up link would have the ability to send a 28.8 stream simultaneously to
every other host on the Internet.  How is that going to work?  If multicast
were flow controlled (a la TCP), it might have a chance, since the amount
of data being injected/created in the network would be regulated by the
amount actually getting out.  If everyone wanted to receive the same thing
we could get by with a 28.8 backbone, and if everyone wanted to receive
something different, we'd need something like the current backbone scaling.
Hmm, that might actually work?  Too bad there is no back pressure in
multicast.

Multicast economies look a lot different whether you are closer to the
source or to the sinks.  I.e., if I am an ISP, and a bunch of my clients
wish to receive the same data at the same time, it's a big win for me (and
the rest of the net), if I can get a single copy, and replicate it locally.
On the other hand, if one of my clients wants to deliver the same data to
a lot people, I would prefer that they buy a bigger pipe, rather than
expecting me to make their copies within my network.  I don't know how ISP
peering relationships are usually structured:  do they pay to receive
packets or to get rid of them?

Tim

---

From: Bill Fenner <[email-masked]>
Date: Tue, 11 Feb 1997 19:04:59 PST

In message <v02130505af26b79c206e@[204.80.124.85]> you write:
>every other host on the Internet.

No, that's broadcast.  With multicast, each person on a 28.8 dial-up link
would have the ability to send a 28.8 stream simultaneously to each host
on the Internet which desires to receive said stream.  Why is this a problem?

  Bill