[Asterisk-biz] Forklift a 2000 phone PBX

[Michael Welter]

steve szmidt wrote:
> On Thursday 24 March 2005 18:42, Michael Welter wrote:
> 
>>I'm staring at an RFP--this company wants to replace a 2000 position PBX
> 
> 
>>The big unknown is wiring.  I'm going to assume the worst, that the
>>existing LAN is overloaded.  I would a) have to make LAN wiring out of
>>existing Cat3 wiring, or b) install a new voice-only LAN.
>>
>>Does anyone know how to qualify existing Cat3 wiring for use as a LAN?
> 
> 
> This seems like a really bad idea. Why lock down into a not only old and 
> outdated technology, but for 2000 users?!!
> 
> You want to keep the network operating efficiently. Modern switches does a lot 
> better job than yesterdays technology. If you have 250 people on the phone at 
> the same time, and you are using g.729, you have used 10Mb right there. Never 
> mind any other protocol.

It's 10Mbps from the IP phone to the LAN switch located in the telephone 
closet, and, unless we put mini LAN hubs in the office, only one IP 
phone will be using this leg.  This leg will also include PoE from the 
LAN switch.  From the LAN switch to the router will be GigaBit Ethernet.

Jim Van Meggelen made a very astute observation that, with a separate 
voice LAN, we won't be encroaching upon the IT staff's domain.
> 
> For 2000 users you cannot think like that. It should be done right or not at 
> all.
> 
> On top of it VoIP is not yet proven to work well under hacking conditions. We 
> know SIP is not very safe in that regard. IAX2 is better but it's still very 
> new. So the safe thing to do is to keep them seperate.
> 
> It's safer to build a dedicated LAN between the PBX and a server as that 
> connection can be really tightend down.

The back-end infrastructure is not the problem.  It's the "last mile", 
from the telephone closet to the user's wall jack, that is the problem. 
  If you've ever fished a cable through the ceiling and down the wall 
then you'll know what I mean.  That times 2000 becomes a serious (and 
expensive) installation problem.  Not to mention the building codes and 
inspection process that goes with new wiring.