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

From: "Jung, Michael" <[email-masked]>
Date: Tue, 11 Feb 1997 09:05:58 -0500

I agree that this should only be a operational question.

It seems that the focus should not be the content of the data
but the quality and salability that data can be delivered.

Speaking for myself, I don't really care if their are thousands
of potential senders of "insert content type here".  The MBONE
or whatever it will evolve to is certainly more progressive the
any unicast alternative.

--mikej

>-----Original Message-----
>From:	Jon Crowcroft [SMTP:[email-masked]]
>Sent:	Tuesday, February 11, 1997 1:34 AM
>To:	Dave Hayes
>Cc:	Paul 'Shag' Walmsley; Van Jacobson; [email-masked]
>Subject:	Re: packet loss between mbone2.UU.Net & SanFrancisco.mci.net
>
>
>
>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:-)
>
> >> 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.
>
>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
>

---

From: Arlie Davis <[email-masked]>
Date: Tue, 11 Feb 1997 11:26:26 -0500

None of this would be a problem if multicast routing worked the way it
is supposed to.

-- arlie

>----------
>From: 	Van Jacobson
>Sent: 	Monday, February 10, 1997 5:37 PM
>To: 	[email-masked]
>Subject: 	packet loss between mbone2.UU.Net & SanFrancisco.mci.net
>
>
>I guess that problems like this are only going to get worse
>(over the past 2 months, the mean packet rate through the
>backbone mrouters has gone from 120 p/s to over 250 p/s)
>since every college in the country seems to think it's very cool to
>broadcast their local radio station on the mbone.  Today I count
>at least 3 of them active -- CMU, University of Missouri-Kansas
>City & University of Missouri-Columbia.  At a time when there's
>new, original, content starting to appear on the mbone, it's a
>shame to have the bandwidth taken away by yet another low
>quality rendition of CDs anyone can buy at the corner store.  Oh
>well, perhaps one day the parties involved will realize they're
>not actually demonstrating a very high level of coolness.

---

From: Bill Fenner <[email-masked]>
Date: Tue, 11 Feb 1997 08:24:04 PST

>I'm not talking about this particular instance of overcommitting, I'm
>talking about the ceiling of MBone bandwidth in general which seems to
>be more mandated by the mrouted 512kbps rate limit than spotty
>overcommitting.

At the last mboned meeting, no providers admitted to rate limiting
(e.g. they all claimed they had turned off mrouted's default).

>But as you might already have discovered, somebody is distributing
>their unicast tables again:

Must be with a high enough metric that it doesn't get to me; I can't
find more than ~6k routes on MCI or DARTNet.  (Or the protection
mechanisms in IOS kicked in, but I thought that was set at 7k).  Looks
like someone in Europe is going to have to track this one down.

  Bill

---

From: "Jung, Michael" <[email-masked]>
Date: Wed, 12 Feb 1997 15:43:30 -0500

The last I heard was that they had (3) T3's.  A current solution
they have is a product called "PointCast Intranet I-Server".

You also can create your own Intranet goodies with it.

--mikej

>From:	Bill Fenner [SMTP:[email-masked]]
>Sent:	Wednesday, February 12, 1997 1:48 PM
>To:	Ross Finlayson
>Cc:	[email-masked]
>In message <[email-masked]> you write:
>>It's really a lot simpler: ISPs are basically "pipe mongers".  Multicast has
>>the potential to reduce the size (& thus cost) of the pipes that ISPs *buy*,
>>and could conceivably (by promoting interesting content) increase the number
>>(& perhaps size) of pipes that they sell.
>
>But what the ISP's mostly see is that it is likely to *decrease* the
>number of pipes they sell.  How many T3's does pointcast currently
>have, and how many would they need if they used multicast?  How about
>audionet.com?  How much of a loss is that for the ISP?  Why would they
>encourage such a move?
>
>  Bill

---

From: Dave Hayes <[email-masked]>
Date: Wed, 12 Feb 1997 15:35:30 -0800

> audionet.com?  How much of a loss is that for the ISP?  Why would they

Look at netnews.

If half the number of netnews posters were to start sending video
streams, is there a technology that will exist that can handle that
much video?

;-)
------
Dave Hayes - Altadena CA, USA - [email-masked] 
Freedom Knight of Usenet - http://www.jetcafe.org/~dave/usenet

Man does not have a capacity of instant comprehension. So rare is the
knowledge of how to train this, that most people and institutions have 
compromised by playing upon man's proneness to conditioning and 
indoctrination instead.
The end of *that* road is the ant-heap. Or, at best, the beehive.

---

From: "Jeffrey S. Curtis" <[email-masked]>
Date: Mon, 17 Feb 1997 14:39:10 -0600

John McGowan writes:
}Dear Dorian R. Kim,
}
}     Are you able to run successfully with PIM *sparse* mode as well as
}dense mode at your site?  If so, were there any startup problems, odd
}quirks?

I'm not Dorian, but for over a year, I've been running sparse-mode
PIM across my site (and across a T1 to a remote site) with a DMVRP
tunnel to an mrouted machine.  It all works fine now; about 15 of
the mrouters are ciscos running 10.2(x) where x is typically between
11 and 15.  The PIM/DVMRP border router is a cisco running 11.0(13)
which seemed to have a memory leak for a while (it steadily lost
100kB/day for two weeks) but that cleared up coincident with the
end of the most recent Mbone unicast routing screw-up.  It probably
wasn't a memory leak at all.

When I first set this up, I needed to run dense-mode in one part of
the network (including where the PIM cloud touched the DMVRP tunnel),
and that led to some serious memory leaks (several MB/day as I recall),
but this was way back around 10.2(7) or so and I believe it was fixed
by about 10.2(7.3).

One other side note - everywhere where I can use multicast fastswitching,
I *don't*.  I've talked to far too many people who've pulled out far
too much hair troubleshooting what turned out to be fastswitching bugs.
cisco tells me that it's considered safe to use at this point, but since
my traffic is light enough that I have spare cycles right now, I'd rather
burn the CPU than worry about whether the traffic is going to get through.

Jeff
-- 
Jeffrey S. Curtis                      | Internetwork Manager
Argonne National Laboratory            | Email: [email-masked]
9700 South Cass Avenue, ECT-221        | Voice: 630/252-1789
Argonne, IL 60439                      | Fax:   630/252-9689