Subject: mboned: RE: comments on draft-hayashi-rac-issues-00

From: Pekka Savola <[email-masked]>
Date: Mon, 7 Mar 2005 02:50:17 +0200 (EET)

(I took out [email-masked] because its reply 
address mechanism appears to be screwed up..)

On Sun, 6 Mar 2005, Manfredi, Albert E wrote:
>>     For NSP to guarantee and charge for a certain quality of data
>>     delivery it is important that they can limit the number
>> of receivers
>>     to a level that their bandwidth and servers can handle.
>>
>> ==> I don't understand this requirement.  We're talking about 
>> multicast here.  Why is a bandwidth reservation important?  Are you 
>> just looking at this at the customer access link or..?
>
> My interpretation was that what needs to be limited is the total 
> number of multicasts available in the network. Certainly, if 
> everyone is watching the same program, there would be no problem 
> (assuming that other traffic is controlled as well, of course). So 
> the "number of different multicast groups available for receivers to 
> join" is a better way of stating this, perhaps, and this also ties 
> into the bandwidth each group requires, discussed in your next 
> comment.

Well.  We're talking about gigabit grade backbones here.  Even with 
the bitstream of 5 Mbit/s per group, even 100 simultaneous groups 
might not be a problem.  Do the content providers even offer that 
many?  Is this a real concern in real networks?

-- 
Pekka Savola                 "You each name yourselves king, yet the
Netcore Oy                    kingdom bleeds."
Systems. Networks. Security. -- George R.R. Martin: A Clash of Kings
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