There are a number of factors to keep in mind when running wireless
networks and voip phones. 

First and foremost, wireless is a shared environment, whereas hard wired
devices are not (or at least you control how many devices are on a
drop). What this means is that the wireless access POD in the ceiling
can accommodate x amount of wireless devices (x depends on manufacturer)
and they all share the upload port. So think of it like this: Our
network ports are by default 100mb, a desktop pc is hardwired inline
with VOIP phones so both share that 100mb port. A robust setup that has
worked for us well for many years. A wireless POD, however, allows up to
16 (for us) connections, so if you have a bunch of carts and voip phones
operating in the same area they will ALL share the 100mb port that the
POD is plugged into. Major slowdown. When a few nurses wander down the
hall then all of a sudden the slow area gets faster as the network hands
over these users to the next closest POD. 

Furthermore, the QOS will give the voip phone priority and, depending on
how your voip is setup, the phone will take the maximum amount of
bandwidth. Voip phones can usually be set (with cisco it can) to a
bandwidth rate which is supposed to reflect where you are. For example,
if I'm at home and using my softphone over a WAN connection the system
will automatically give me a low bandwidth phone connection (not as good
a quality but manageable). Anywhere internally over our network the
system will use the maximum to provide the best quality phone call. 

One solution that you can try is to up your amount of wireless pod's
that cover the problem area. Personally I would call in your wireless
company and have them do a study so they can recommend a proper answer.
If you have wireless monitoring software you should be able to do a
report on the PODS in that area to see if they are overloaded. Along
with that possible solution you then also look at setting your POD to
allow less connections at the same time so they will then automatically
go to the new POD and that will then give users more speed. (most
systems will automatically shuffle users to other available PODS to
maximize throughput). 

Another solution is to look at throttling back your voip phone bandwidth
usage for wireless connections - but I would go with more pods first as
dropping bandwidth often equates to lower quality phone calls and no-one
likes that. Testing, however, would allow you to consider if it's worth
it. 

What I have found is that the very benefit of wireless, mobility, can
cause havoc with managing networks. You can design you wireless POD
layout perfectly only to find out months later that the 'gathering' area
where staff congregate has moved and now you have lots of coverage in
the area they no longer go to and not enough POD coverage in the new
area. This then,  in turn, causes slowdowns and frustration and is
always IT's fault. 


The wireless world, more so than the hard wired world, is a constantly
evolving beast. I therefore highly recommend using software that can
tell you how the POD's are faring - are they constantly overloaded, are
they under utilized, etc. etc. That will help you ensure you have
adequate POD's in the needed areas. 

Also, don't forget that wireless is a 3 dimensional world, where POD's
from the floors below and above can also assist with network connections
as long as they reach the affected area. 

Hope this helps...

Gary Gevaert
 
>>> Practice Random Acts of Kindness and Senseless Acts of Beauty <<<
 
Project Analyst
Niagara Health System - Shaver Site
DataCentre Building
541 Glenridge Avenue
St. Catharines, Ontario L2T 4C2
www.niagarahealth.on.ca
 
Phone:   905-378-4647 x 44806
 

-----Original Message-----
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of Gearry Judkins
Sent: July 3,2007 1:01 PM
To: Moody, Barbra
Cc: Meditech L (E-mail)
Subject: Re: [MEDITECH-L] Wireless and VoIP

Moody, Barbra wrote:
> Hello Everyone,
>
> We are having problems with our wireless carts and our VoIP and we
aren't sure exactly what's happening.  We know that when our VoIP
communication devices hit the wireless network it knocks everything down
to B from G and slows everyone down.  We were told that we couldn't run
them on 2 different networks because the would clash.  This is making
PCS run so slow on the carts that the nurses are complaining loudly.  It
is much slower than the PC's at the desk.  Have any of you had problems
like this or have any suggestions?
>   
Are your Wireless VOIP phones B only?  A single B/G wireless radio can 
not operate in both modes at the same time.  If 802.11B is enabled, the 
entire radio will throttle down to the B mode once there is an 802.11B 
device associated.  That means all other B/G devices in that footprint 
also need to throttle down to communicate with the access point.  I 
suspect this is what is currently happening.  You can also easily run 
into bandwidth problems if your AP density is very low, causing many 
devices to share access points.

Another factor that could contribute to this is QOS.  If your VOIP vlan 
gets priority, than other devices are going to get diminished 
performance when VOIP uses large amounts of bandwidth.

However, based on your description I would guess that the first scenario

is more likely.

Gearry Judkins
Information Systems
Franklin Community Health Network

=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=
To subscribe or unsubscribe to the meditech-l, visit
http://mtusers.com/mailman/listinfo/meditech-l_mtusers.com

To check the status of the meditech-l, visit MTUsers.NET

For help, email [EMAIL PROTECTED]

Please visit and add information to the MTUsers WikiPedia at
MTUsers.NET/mwiki
______________________________________
meditech-l mailing list
[email protected]
http://mtusers.com/mailman/listinfo/meditech-l_mtusers.com


Confidentiality Notice:
This e-mail message, including any attachments, is for the sole use of the 
intended recipient(s) and may contain confidential and privileged information. 
Any unauthorized review, use, disclosure or distribution is prohibited. If you 
are not the intended recipient, please contact the sender by reply e-mail and 
destroy all copies of the original message.

=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=
To subscribe or unsubscribe to the meditech-l, visit 
http://mtusers.com/mailman/listinfo/meditech-l_mtusers.com

To check the status of the meditech-l, visit MTUsers.NET

For help, email [EMAIL PROTECTED]

Please visit and add information to the MTUsers WikiPedia at MTUsers.NET/mwiki
______________________________________
meditech-l mailing list
[email protected]
http://mtusers.com/mailman/listinfo/meditech-l_mtusers.com

Reply via email to