[VoiceOps] using a T1 to extend PRI service and involuntary fax over sip

[Paul Timmins]

On 01/24/2011 05:08 PM, Lonny Clark wrote:
> Most point-to-point T1s that are provisioned are now being backhauled 
> over IP. This means that the T1 has to be encapsulated in an IP 
> stream, and the timing for the T1 is also embedded in the stream. Any 
> slips in the timing may be masked by the backhaul method (you won't 
> see an alarm). It also means that now you have the possibility of a 
> dropped or out-of-order packet, which was not possible if the circuit 
> were T1/T3 all the way through. The possibility of timing issues would 
> also be increased by the fact that now you are encapsulating twice, 
> once in the point-to-point T1, and also at the SIP-to-PSTN interface 
> (assuming the PSTN link is TDM). The fax-to-email service itself has 
> to also demux the data, and then interprets the result of that as an 
> analog stream using software.

Are you really seeing that much PWE3 pseudowire out there? Every time 
I've looked it has no benefit over SONET other than more trouble 
tickets, unless you really, really have decent QoS and almost no need 
for TDM service in an area you simply can't get SONET to.

That being said, on the CLEC side, I have seen no real demand for PWE3 
psuedowire out there at all. It's just more expensive and problematic 
than the time tested, more widely available TDM gear.

Not saying there isn't a huge demand for IP to the edges, but replacing 
perfectly good sonet with IP, just to carry less traffic due to IP and 
PWE3 overhead? I'm just not seeing it.

-Paul