Contention/Oversubscription maths

Adam Armstrong lists at
Fri May 27 12:14:19 UTC 2011

On 27/05/2011 03:12, Valdis.Kletnieks at wrote:
> On Thu, 26 May 2011 23:48:48 BST, Adam Armstrong said:
>> Finally, what do people think of selling a 1G service with 1G backhaul
>> (and potentially 10s or 100s of customers buying this service alongside
>> n*100s of customers with 100M service)?
> Depends what weasel words you put in your SLA, I suppose.  Can they
> claim SLA credits for it being down/unusable if they're only getting 1% of
> the throughput they paid for?  And are they a captive audience or not?
No SLA, residential customers.

1% is quite unlikely to happen, it would require every customer in a 
very large deployment to be trying to download >1mbit/sec at the same time.

Peak average usage for most UK broadband installations seem to be 
between 20 and 100Kb/sec. I'm working on the basis of 300Kb/sec because 
our access speeds are much higher.

(this would suggest 300Mbit/sec peak for 1000 users, but my question is 
whether we'll see that level of aggregation at 1000 * 100Mb on 1GE, or 
whether it's going to be very 'peaky', and we'll only see that 
smoothness when we aggregate 10-15 buildings onto 10GE)

> What do you do on Patch Tuesday?

Update windows.


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