[Cu-wireless] channel allocation; subnet routing; dhcp

Ralph Johnson johnson at cs.uiuc.edu
Thu May 2 04:04:53 CDT 2002


I need to start coming to meetings so I understand what you are talking
about.  This week, unfortunately, I was dealing with a flooded basement.

>From: David Young <dyoung at onthejob.net>

>I can understand the desire to keep the routing tables compact, but subnet
>routing seems unnatural for a wireless network. Will OSPF bog down if
>we do not use subnets? Every host in a subnet needs to be individually
>routed, anyway....

The whole idea of subnet routing is that things in a subnet are not
individually routed.  So, if you are individually routing to the
elements of a subnet then you are not using subnet routing.  Am I
missing something? 

My understanding is that a few thousand entries in the routing table
is no big deal.  Millions are a problem.  Are you talking about just
Champaign-Urbana?  If so, what is the point of subnet routing?

>To get the most links, you want to use the fewest channels. To achieve
>least contention, you want to use the most channels. But if you have a
>channel per station, you have zero connectivity.

Can't you use three channels without contention?  Also, if your
antennas are directional, you could have several antennas on the
same channel without them interfering.  For example, I'm thinking
of using patch antennas up and down a street.  A house could use
channel 1 going north and channel 12 going south.  It could use
channel 7 on an omnidirectional antenna.  Suppose this street was
north/sourth.  A house on the south corner might use channel 12 going
east as well as channel 12 going north.

-Ralph




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