Subject: Re: Multicast Last Mile BOF report

From: "Kevin C. Almeroth" <[email-masked]>
Date: Tue, 15 Jul 2003 22:52:57 -0700

>>> The problem being tackled isn't completely clearly defined, but the
>>> general philopshy is that multicast is not being deployed because most
>>> potential receivers are using ISPs that don't supply multicast
>>> service.  The proposal is that we need some form of auto-tunnelling
>>> protocol which would allow a receiver to request unicast tunnelling of
>>> multgicast traffic from a replicator somewhere on the
>>> multicast-capable internet.  Such proposals have come up repeatedly
>>> over the last ten years.
>>
>>there is a serious contest to see how many mechanisms multicast
>>and v6 can develop to overcome why they are not being deployed.
>>they should get a clue.

Look at how many mechanisms NAT required before it was deployable.

Ease of deployment != good

-Kevin

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From: Randy Bush <[email-masked]>
Date: Wed, 16 Jul 2003 08:21:55 +0200

> Look at how many mechanisms NAT required before it was deployable.

there was demand for nat.

> Ease of deployment != good

and 500 gadgets do not make a technology adopted when it has no
business model folk can understand.

randy

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From: Keith Moore <[email-masked]>
Date: Wed, 16 Jul 2003 09:19:10 -0400

] and 500 gadgets do not make a technology adopted when it has no
] business model folk can understand.

one business model that might be understandable is: you should support
multicast if/when it saves you enough bandwidth (over the same content
being sent over separate unicast streams) to make it worth your cost.

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From: Masataka Ohta <[email-masked]>
Date: Wed, 16 Jul 2003 22:48:06 +0859 ()

Keith;

> being sent over separate unicast streams) to make it worth your cost.

It means it saves nothing for receivers that they don't want to
receive multicast stream.

Then, senders are not motvated to send multicast stream.

Also, the bandwidth saving is beneficial to ISPs that ISPs supporting
multicast should charge less to its customers. It's not bad if ISPs are
competitive and backbone bandwidth were expensive.

								Masataka Ohta

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From: Randy Bush <[email-masked]>
Date: Wed, 16 Jul 2003 16:04:05 +0200

> being sent over separate unicast streams) to make it worth your cost.

if i needed to save bandwidth, which is not demonstrated as i sell it
</sarcasm>, that there is no content my customers want means i will add
capex and opex to save no bandwidth.

randy

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From: Keith Moore <[email-masked]>
Date: Wed, 16 Jul 2003 10:02:21 -0400

On Wed, 16 Jul 2003 22:48:06 +0859 ()
Masataka Ohta <[email-masked]> wrote:

] > one business model that might be understandable is: you should support
] > multicast if/when it saves you enough bandwidth (over the same content
] > being sent over separate unicast streams) to make it worth your cost.
] 
] It means it saves nothing for receivers that they don't want to
] receive multicast stream.
] 
] Then, senders are not motvated to send multicast stream.

maybe the ISPs supporting multicast could prioritize that traffic, thus 
providing better service on multicast than unicast, thus providing an
incentive for receivers to use multicast over unicast.

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From: Masataka Ohta <[email-masked]>
Date: Wed, 16 Jul 2003 23:04:17 +0859 ()

Keith;

> incentive for receivers to use multicast over unicast.

Prioritization is orthogonal to uni/mulitcast issue.

Users will favour those ISPs which prioritize unicast and pay more money.

Other users may use the prioritized multicast for 1:1 communication.

							Masataka Ohta

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From: Keith Moore <[email-masked]>
Date: Wed, 16 Jul 2003 10:20:21 -0400

] Users will favour those ISPs which prioritize unicast and pay more money.

more money will nearly always buy more bandwidth.

] Other users may use the prioritized multicast for 1:1 communication.

the trick is to only prioritize multicast for which there are enough listeners.
but this seems doable.

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From: Keith Moore <[email-masked]>
Date: Wed, 16 Jul 2003 10:17:36 -0400

] >> and 500 gadgets do not make a technology adopted when it has no
] >> business model folk can understand.
] > one business model that might be understandable is: you should support
] > multicast if/when it saves you enough bandwidth (over the same content
] > being sent over separate unicast streams) to make it worth your cost.
] 
] if i needed to save bandwidth, which is not demonstrated as i sell it
] </sarcasm>,

if your customers pay flat rate and you can deliver them the same or better
service at less cost to you, isn't this at least some incentive?
(perhaps not enough to overcome your costs?)

if your customers pay per megabyte and they can get better service at
less cost by using multicast, isn't this also an incentive of a different
sort?

] that there is no content my customers want means i will add
] capex and opex to save no bandwidth.

indeed, lack of content is a problem.  multicast won't fly unless/until 
there is content available through it that lots of people want to get.  
IETF meetings are great for me but they have a limited audience overall.

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From: John Stracke <[email-masked]>
Date: Wed, 16 Jul 2003 10:17:32 -0400

>incentive for receivers to use multicast over unicast.
This would provide an incentive to game the system and use multicast 
even if you had only one receiver.

Isn't the real problem the fact that the set of streams that people 
might receive is so diverse, most links won't be carrying more than one 
copy of the unicast stream anyway? Multicast would help only at the 
sender's end, in the case of flash crowds; and the sender's ISP has no 
incentive to shrink the size of the bitpipe the sender needs to buy.

-- 
/==============================================================\
|John Stracke      [email-masked]                       |
|Principal Engineer|http://www.centive.com                     |
|Centive           |My opinions are my own.                    |
|==============================================================|
|"But she calls her ship _Mercy of the Goddess_!" "Kali." "Oh."|
\==============================================================/

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From: Randy Bush <[email-masked]>
Date: Wed, 16 Jul 2003 16:22:54 +0200

let's get real here.  though we have been pushing it since i was
in nappies (and i have deployed it in isp(s), and i also donate
to hopeless progressive causes), there is far more email traffic
about multicast than there is actual multicast traffic on the WAN
internet (yes, it is heavily used on a few LANs).

randy