[Cerowrt-devel] Coping with wireless-n [#305]

Dave Taht dave.taht at gmail.com
Thu Dec 8 07:09:18 EST 2011

On Thu, Dec 8, 2011 at 12:51 PM,  <david at lang.hm> wrote:
> On Thu, 8 Dec 2011, Dave Taht wrote:

> this puzzles me.
> splitting 2.4G and 5G into different different networks (broadcast domains)
> is a huge win. cince I can't find any open implementation fo band steering,
> this requires putting the two bands on different SSIDs.

Oh, god no, I'm not dropping that. Having those split AND off the wired
network is staying in...

> but I don't understand why there is a big problem with G and N sharing the
> same SSID.

Because you can fully FQ G, and if you do that to N, it messes up aggregation.

> there is some


> grief with having different speeds on the same channel, but
> only in that the same amount of data will take longer to transmit (causing
> problems with predicting how long the queue is in terms of time as it will
> vary on the destintation), but even if you stick with G for example, it can
> transmit at 54, 48, 36, 24, 18, 12, 6, 1 Mb/s. adding N just adds some
> higher speeds to this. If the devices are configured sanely, they should be
> transmitting the header for a G frame to reserve the air time and then
> sending the N frame inside of that. this has a slight overhead compared to a
> pure N network, but it doesn't matter if the G network is on the same SSID
> or on a different one, the problem is sharing the airtime on the channel.

It's a packet scheduler test more than anything else.

> David Lang

Dave Täht
SKYPE: davetaht
US Tel: 1-239-829-5608
FR Tel: 0638645374

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