Installing DD-WRT -

Tim ignored_mailbox at
Sun Aug 22 06:42:41 UTC 2010

>> All your wireless devices transmit on the same channel.

> yes and no. depends on manual assignment.

Well, generally speaking, your access point only works on one channel,
and all the clients use the same one.  If you have two access points on
the same channel, such as across a large site, your clients use the one
with the strongest signal, with the clients being on the same channel
two.  But it's less problematic to have your access points on different
channels (less likely to have spots where reception won't work), and the
clients will change channels to suit the access point they're using.
Generally speaking, an access point doesn't change the channel that it's
using, after its setup.

Going from what I understand of Bob's setup, he's got one access point
and several clients.  Those clients may have inbuilt wireless, or they
may connect to a dongle/box to provide wireless networking.  In that
case, they would all be on the same channel.  Even if he connected a
separate DHCP server, it would be yet another client, rather than act as
an access point (providing networking service to other clients).

>> With wired networking, through a switch or router, many devices can all 
>> talk simultaneously, if they're each talking to different devices.

> again, yes and no. with a switch, yes.
> with a router, no. again, first to transmit/first heard.

Only if you're talking about /through/ the gateway, or different clients
wanting to talk with the same device.  Half a dozen clients all talking
to each other, or anything else within the LAN, can do so
simultaneously.  i.e. Pairs of chatting devices that aren't talking to
something else that's busy.

> for wireless, what is needed, if not already, is ability for each interface
> to monitor in a delayed channel switch scan mode.
> when a signal is received, interface would listen for it's ip. if being
> 'called', it then replies and communications are established.
> if interface needs to communicate, it would first scan for an open channel,
> then send destination ip address and listen for reply.

Generally, when there's more than one access point available to you,
whether they're part of the same LAN or not, your client will do one of
a few things:

  Connect to one, and ignore all the others, until /you/ quit.

  Use the same one as last time.

  Use the one with best reception that it's authorised to use.

  Switch between access points if reception drops off the current one.

  Use the one the user manually selected.

What isn't going to happen, with the usual way things run, is:

  To connect and disconnect while idle.  Once it's connected to one, it
  keeps using the same one for the whole session, unless a problem crops
  up.  NB:  I'm not talking about continuous RF transmission, I'm
  talking about continuous association with the same access point.

  To switch access points if the one that you're currently set up to use
  is too busy.

[tim at localhost ~]$ uname -r

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