Inherited Linksys Voice over IP and data installation.

Question

I have just inherited a brand new linksys, voice over ip data installation. It has roughly 25 telephones and the same number of computers with new WMP300N network cards and SPA941 IP telephones. The company remodeled an old construction with 100% masonry wall (brick and/or concrete). The remodeling included the 100% wireless data and telephone installation. Now that the remodeling is finished and work has started, the network saturates as soon as there are a few users. The computers are all using LinkSys WMP300N cards and the telephones are all LinkSys SPA941. They installed approx 15 wifi repeaters for telephones and 10 for datos. They installed two separate but identical AP's, one for Data and the other for Voice but both on a 192.168.1/24 subnet.(Zonet ZSR1124WE) The folks who installed this didn't, for some reason, use LinkSys AP's and repeaters but used Zonet ZSR1124WE for all.
My questions are:
1. Wouldn't using the same subnet be the same and using the same
wire that that would allow voice/telephones to saturate and
slow down the data even though the AP's are separate?
2. Wouldn't channel interference between the aprox 25
repeaters be common?
3. If I were to remove all their equipment (APs and repeaters.)
an install 2 LynkSys AP's in the center of the offices
where there is an open patio with a watt or better amplifier
(not illegal here, not in the U.S.) output and a high gain
antenna on each of the two and using separate networks.
172.16.1/24 for datos and leave 192.168.1/24 for telephones
have a chance at success and if so could you estimate
how much of a change and recommend equipment and/or other
critical or semi-critical points that I have missed?
Thanks,
ed
P.S. I have my doubts that this is even possible but it would be cool, if it only worked

Answer 1

Umm.. you left out quite a bit of information:
How are the wired phones connected to the wireless network?
What channels do the APs use and how are they connected in between each other (and other wired data equipment)?
What kind of network is it? B, G, N?
How many WLAN channels are used? One per AP and all repeaters use the channel of the AP they repeat for?
As far as the subnet goes, the current setup shouldn't be a problem - I figure the problems are more likely to come from the wireless than the wired part of your network. Considering that you're basically halfing the throughput with each repeater (assuming the same channel which is likely since there are only 3 that do not interfere unless you have an A network) - the sheer number of repeaters is most likely to be blamed for the poor performance. Traditional WLAN networks generally use a wired backbone, plus you'd have a single net and use one of the three distinct channels in order to minimize interference.
Increasing the output of the main antenna is also only half of the problem... if you can reach clients that are farther away, those clients will also need the appropriate power output to reach the base again - and those wireless cards are limited in that way.
There are two essential pieces to tracking down a problem with your VoIP equipment:
The configuration of every device involved
SIP protocol traces
And don't forget: there's no such thing as giving too much information when describing a problem.