[38678] in North American Network Operators' Group

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Re: Multicast Traffic on Backbones

daemon@ATHENA.MIT.EDU (Eric Gauthier)
Sun Jun 10 13:46:54 2001

Date: Sun, 10 Jun 2001 13:44:19 -0400
From: Eric Gauthier <eric@roxanne.org>
To: Michael Whisenant <mwhisen@foreigner.whisenant.net>
Cc: Tim Winders <twinders@SPC.cc.tx.us>,
	Joshua Goodall <joshua@roughtrade.net>, Deepak Jain <deepak@ai.net>,
	"Nanog@Merit. Edu" <nanog@merit.edu>
Message-ID: <20010610134419.B6210@roxanne.org>
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In-Reply-To: <Pine.LNX.4.33.0106100753180.9619-100000@foreigner.whisenant.net>; from mwhisen@foreigner.whisenant.net on Sun, Jun 10, 2001 at 08:05:24AM -0500
Errors-To: owner-nanog-outgoing@merit.edu


> they not be compensated for the flow? If you are going to have N times
> receivers of your stream, should they then not have the ability to charge you
> some factor greater than 1 to support the flow? One method is to limit the
> amount of bandwidth of multicast per edge interface, but if a 128K stream is
> sent to hundreds or thousands of places then it could impact certain links as
> well. Maybe not the backbone running at OC-x speeds...

I'm relatively new to multicasting, but my impression is that if you have a
128K stream that you are sending out then, even if you are sending it towards 
hundreds or thousands of places, no individual link would have more than 
128K on it (thus the point of multicasting).  There may be hundreds of 
different links each with an additional 128K, but the N-factor amplification 
you are referencing would be more from the "we now have to send this same 
128K out 20 different peering links and possibly (depending on your peering
policy) pay 20 times the bandwidth cost" but it shouldn't cause any 
individual link to become overloaded.

Eric :)

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