Big Temporary Networks

joel jaeggli joelja at bogus.com
Sun Sep 16 16:42:27 UTC 2012


On 9/16/12 9:24 AM, Jay Ashworth wrote:
> ----- Original Message -----
>> From: "Gaurab Raj Upadhaya" <gaurab at lahai.com>
>>> So you're *REALLY* motivated on this "reduce the coverage" thing,
>>> then.
>> you could say yes :), reduce the coverage per-AP. Most APs I have seen
>> will start failing with about ~100 associations and not to forget
>> about the max GE uplink they have. that's about 40-50 people at most
>> (being optimist).
> Really?  100 associations?  On enterprise/carrier grade gear?
>
> Seriously?
We tend to engineer for a maximum of around 50 associations per radio 
(not AP). beyond that performance really starts to suck which can be 
measured along a multitude of dimensions. The most visible one to the 
client(s) being latency due to loss and subsequent retransmission.

Reduction in coverage is done on a couple of dimensions. that ap with  
the 3-5dBi gain dipoles probably shouldn't  be 100mW. but the noise 
floor is in a different place when the room is full of clients so it 
can't be to low either. Dropping the low speed rates backward 
compatibility with 802.11b and setting the multicast rate to something 
higher will force clients in marginal coverage situations to roam more 
quickly, hog the air less and allow for higher throughput.
>>>> g) we have a /32 and /20 (v6 and v4 respectively) address space
>>>> assigned by APNIC for this and other events in Asia (including
>>>> the APNIC meeting itself) so we use that. We used to have a v4
>>>> /16 though before runout.
>>> I'm talking to someone from the Interop team; they have a dedicated
>>> /8.
>> They gave that 45/8 back and kept 2 x /16 for themselves.
> I did not know that.  Good on 'em.
>
> Cheers,
> -- jra




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