Network end users to pull down 2 gigabytes a day, continuously?

Marshall Eubanks tme at multicasttech.com
Wed Jan 10 06:53:40 UTC 2007


On Jan 10, 2007, at 1:49 AM, Marshall Eubanks wrote:

>
> Dear Valdis;
>
> On Jan 9, 2007, at 10:02 PM, Valdis.Kletnieks at vt.edu wrote:
>
>> On Tue, 09 Jan 2007 11:29:32 EST, Gian Constantine said:
>>> If you considered my previous posts, you would know I agree  
>>> streaming
>>> is scary on a large scale, but unicast streaming is what I  
>>> reference.
>>> Multicast streaming is the real solution. Ultimately, a global
>>> multicast network is the only way to deliver these services to a
>>> large market.
>>
>> Multicast streaming may be a big win when you're only streaming  
>> the top
>> 5 or 10 networks (for some value of 5 or 10).  What's the performance
>> characteristics if you have 300K customers, and at any given time,  
>> 10%
>> are watching something from the "long tail" - what's the  
>> difference between
>> handling 30K unicast streams, and 30K multicast streams that each  
>> have only
>> one or at most 2-3 viewers?
>
> This is a very good point. It is very reasonable to expect viewing  
> choices to follow
> a Pareto distribution (such as Zipf's law or the 80-20 rule). That  
> plus some reasonable
> economic assumptions make 30K commercial channels not an  
> unreasonable assumptions in a
> few years. But that also implies that it is _not_ realistic to have  
> "30K multicast streams that each have
> only one or at most 2-3 viewers." You may have 30K streams, most  
> may have only a few viewers, and
> still have fairly large savings.
>
> To flesh out your example,
> if you have 1 million viewers on your network, and if you assume  
> 30K channels and
> the same Pareto distribution as web sites,
>
> - the largest channel has 1.8% of the audience
> - 50% of the audience is in the largest 2700 channels
> - the least watched channel has ~ 10 simultaneous viewers
> - the multicast bandwidth usage would be 3% of the unicast.
>
> These same models IMHO makes cell phone RF multicast not incredibly  
> compelling. Because there is less
> feedback on a multicast RF, the power has to be greater for a  
> multicast channel, and
> in that case the bandwidth (or RF power)  savings are small or even  
> negative, because you only
> have maybe 100 people on a cell watching.

s/watching/watching content from your 30K channels/

Regards

>
> Regards
> Marshall
>




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