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

From: Dave Hayes <[email-masked]>
Date: Mon, 10 Feb 1997 20:24:01 -0800

"Paul 'Shag' Walmsley" <[email-masked]> writes:
> As I am one of the individuals who is currently multicasting one of the
> radio stations that Van mentioned (KCOU), I think that some discussion on
> this topic will be at the worst informative and at best entertaining.  

Actually, at the worst, Mr. Jacobson and others who feel similarly will
not respond to this thread. I think this subject needs discussing as
well, if only for a bit.

> At this point [Van] state[s]:
...
> > since every college in the country seems to think it's very cool to
> > broadcast their local radio station on the mbone.  
> ... this is certainly contradictory ("every college in the country"
> != 3), but it also seems potentially misleading.  I think it is
> misleading since there seem to be other much more serious problems
> confronting the MBONE other than college radio stations,

Agreed. The magnitude of other problems, however, does not alter
the existance of the original problem...if any.

A "more proper" response to Van Jacobson is forthcoming.
------
Dave Hayes - Altadena CA, USA - [email-masked] 
Freedom Knight of Usenet - http://www.jetcafe.org/~dave/usenet

            "It is a dragon, destroyer of all," cried the ants. 
                      Then a cat caught the lizard.

---

From: Jon Crowcroft <[email-masked]>
Date: Tue, 11 Feb 1997 06:33:46 +0000

i think this is an operational question, not a poltical/content one

when a router is breaking thains on the mbone, but a reduction in
traffic will fix things, we (the community) have established a 
priority for what we ask to turn off......

in the absence of congestion (whether from link or router, or broken
config overload), nobody minds anythinbg being sent - why would they?
this is the Internet:-)

 >the existance of the original problem...if any.

we could re-examine the priority above ...but i suspect that we'd
probably end up with the same answer

if the nets in trouble, keep ephemera of local interest local (drop
that ttl).....mboned seminars seem to me to be pretty vital....as does
NANOG....which after all, might be the very place they get to fix the
router or congestion problems 

[i take it you guys know what NANOG is, right? :-)

 jon

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From: "Giorgio Ventre (Dipartimento di Informatica e Sistemistica)" <[email-masked]>
Date: Tue, 11 Feb 1997 11:36:38 +0100

> config overload), nobody minds anythinbg being sent - why would they?

I would say that this operational issue has a huge political
implication.
The problem is how a community like Internet can manage decisions on the
allocation of scarce resources. Until today, the problem has been solved
by having a restricted group of experts monitoring the traffic and
intervening in case there would be congestions that could endanger one
or two "interesting" events. 

I just wonder what can be used as the metric to define "interesting to
the MBone" an event. The size of the attendance surely not, since I can
bet that even NANOG will have troubles if competing with a live concert
of *your favorite rockstar name here*...   

Since there are no secure *and* reliable *and* fair mechanisms in sight
that will solve this problem in the near future, I believe that we need
to find an alternative approach.

Even we accept the reality that this will not avoid that a misconfigured
application/router/anything will destroy the MBone, at least we should
think to something that can try to manage the available resources with
fairness. Peer reviewing might be an approach at least to start.  

-- 

===========================================================================
Dr. Ing. Giorgio Ventre					
Dipartimento di Informatica e Sistemistica		Tel: +39 81 7682891
Universita' di Napoli Federico II			Fax: +39 81 7683186
Via Claudio 21, 80125 Napoli, Italy	  e-mail: [email-masked]
===========================================================================

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From: Jonathan Day <[email-masked]>
Date: Tue, 11 Feb 1997 13:23:24 +0000 (GMT)

> to find an alternative approach.

IPv6 /might/ solve that one by setting priorities and flow-labels, but
it'll be a loooooong time before it's sufficiently widely used to even
find out if the claims are true, let alone make use of them.

/However/, some automatic mechanism for preventing any one stream from
blocking others, for IPv4 multicasting, should be simple enough to write.
As for fair, well, that usually depends on what side of the knife you're
on when things start getting cut. /Reasonable/ is often far more achievable
than /Fair/.
 
> fairness. Peer reviewing might be an approach at least to start.  

The net as a whole is unbelievably fragile. Large segments of the net,
both unicast and multicast, often vanish when a single link goes down.
Vast sections are often heavily lagged, and links easily get overloaded.
The 'Intertree' sounds a lot sillier than the Internet, but it would
seem to reflect rather more honestly the level of redundancy on some
parts of the net.

Jonathan

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From: Jon Crowcroft <[email-masked]>
Date: Tue, 11 Feb 1997 14:42:35 +0000

>find out if the claims are true, let alone make use of them.

s/ipv6/red|int-serv/g

 >seem to reflect rather more honestly the level of redundancy on some
 
there is some in some palces, but there's no global
coordination.....

its a mes[h]...

cheers

 jon