Subject: RE: BitTorrentvs MBONE

From: "Hallam-Baker, Phillip" <[email-masked]>
Date: Thu, 15 Sep 2005 19:34:47 -0700

> Behalf Of Michael Thomas

>    Are we to believe that they are largely self-healing problems
>    as bad p2p apps will eventually correct themselves since it's
>    in their interest? Is it reasonable to believe that there is
>    enough general clue that they could be expected to do that?
>    And the collective clue of the ietf is not really needed to
>    help this along?

Last time I heard that type of talk it was from all those folk who just
had to tell us why the network hypertext project we were working on at
the time was certain to be a collosal failure.

In terms of bandwidth headroom the Internet seems a heck of a lot better
off today than in the early days of the Web when people thought a T1 was
the ultimate in network connection. 

Sure bittorrent is probably not great design by many standards. Neither
is NNTP, a protocol which used to rip up about half the Internet
bandwidth churning bits around that almost nobody would ever read.
Pre-emptive flood fill is an 'interesting' strategy to say the least.
Many ISPs no longer support it. Comcast charges extra.

I think that the reasonable question to ask here is 'does MBONE have a
future?' If I was asked to design a new media distribution protocol from
scratch I certainly would not choose MBONE as a model. The technical and
political problems both appear insoluble to me.

To return to the original question. The IETF is certainly capable of
solving complex problems. What it does not appear to be capable of is
letting go of failed experiments. Take multicast out to the woodshed,
its long overdue. 

_______________________________________________
Ietf mailing list
[email-masked]
https://www1.ietf.org/mailman/listinfo/ietf

---

From: Tim Bray <[email-masked]>
Date: Thu, 15 Sep 2005 19:52:49 -0700

On Sep 15, 2005, at 7:34 PM, Hallam-Baker, Phillip wrote:

> Sure bittorrent is probably not great design by many standards.

For the record, I think bittorrent is a superb design, especially  
when seen as a first cut.  It will improve. -Tim

---

From: John Kristoff <[email-masked]>
Date: Thu, 15 Sep 2005 22:30:14 -0500

On Thu, 15 Sep 2005 19:34:47 -0700
"Hallam-Baker, Phillip" <[email-masked]> wrote:

> future?'

It doesn't even have a present.  It's long gone.  Native multicast
on the public Internet seems to continue to have a future, but only
for a continued subset of the global Internet.  I've heard some talk
of renewed interest in multicast deployment, but I'm skeptical.  If
you look at some statistics [1] you find:

  About 450 ASNs (and not just .edu's) representing about 5000 routes
  seen via MBGP.

  These routes expand to cover about 125,000,00 million possible
  addresses (compared to about 1.1 billion addresses covered by a
  current unicast table).

  There are about 1,300 (not totally and obviously bogus) SAs.

What is interesting is that these numbers haven't moved all that much
over the past few years.  Multicast deployment has peaked, but one
might consider 10% (using address coverage as one measure) to be
pretty widely deployed.

What seems to have pretty strong and probably growing interest is site
local multicast applications such as file/image distribution and Video
over IP.

> If I was asked to design a new media distribution protocol
> from scratch I certainly would not choose MBONE as a model. The
> technical and political problems both appear insoluble to me.

They are.  Even after the MBONE, large-scale multicast is still quite
hard.  I think this paper captures the general sentiment pretty well
and I bet a few other operators who have had similar multicast
deployment experience will be nodding their heads with a familiar
feeling of shared pain as they read through Section 2:

  <http://gravity.lbl.gov/grbell/docs/RIPQOS-GRBell.pdf>

Even if you could get past the complexity issue, I would contend
that you would also need to overcome the security fears real (and they
are in the multicast case) or imagined whenever it requires the netops
people to have turn 'something on'.  Today, it is more likely that
things get turned off, rather than turned on and that has real serious
implications for how new things get deployed, which I'm sure is no
secret to you and most others here.

[1] http://www.multicasttech.com/status/

John