Multipoint bridge link throughput

[ipeers]

I have been listening to the PLEC WLAN course and am a bit unclear about the multi site scenario whereby there is a main building with 3 or 4 other sites being fed by an omni directional aerial.The course example is that the main site is capable of running at 11 meg but the satellitesare set to 2 meg perhaps because of distance so that each site's max. speed is 2 meg.The speaker goes on to intimate that if there was another site that was very close to the main building it could run at 11 megs,but is this using the same bridge as everyone else or a separate one used just for an 11 meg link

[kmarrero]

This scenario is using the same bridge. Keep in mind that usually the Mps is going to fluctuate due to the distance and interference that may be in between the main site and the remote sites.

[ndoshi]

Available bandwidth between bridge depends on many factors like distance between the bridges , interference , signal quality etc .

Say if you have 3 bridges , A , B and C . A being hub and B and C as spoke .

B and C will be non root and they are client to A . A has Max 11 meg and this 11 meg is shared between B and C .

If you want 22 meg than you need two pair of bridge

br1--------br2

br1a-------br2a

you can have max 33 meg as there are 3 overlaping channels 1, 6 and 11

so ,

br1--------br2

br1a-------br2a

br1b--------br2b

Nilesh

[ipeers]

Nilesh - the question I'm asking is this - if spoke site B can only run at say 2 megs because of distance or whatever can site C which might be really close and therefor able to run at 11 megs run at 11 megs ,in other words mixed speeds - I suspect not but the Cisco notes are a little ambiguous

[derwin]

Yes you can have clients all running at different speeds

As a client moves further away from the AP it will step down the speed in order to maintain a reliable connection, this will have no bearing on the operation of clients that are closer to the AP

You can configure on the AP the minimum speed that you what the clients to drop down to The paramter you use to configure this is Data rate on the Radio hardware page. Please see this link for further details

http://www.cisco.com/univercd/cc/td/doc/product/wireless/airo_350/accsspts/ap350scg/ap350ch3.htm#15458

David

[ipeers]

David,

thanks for your reply however the question is about bridges not access points - I am talking about a root bridge feeding perhaps 2 or 3 remote sites via an omni directional antenna.The question is can 2 of the remote sites be running at say 2 meg because of distance away from hub (main) bridge and the third site run at 11 megs because it is much closer and the signal is better

[derwin]

The way this works is the same for bridges and AP's as they both use the same media access and phy layer methods

So the answer is YES