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

[Lonny Clark]

My company is a CLEC + ISP, and we are using a lot of pseudowire. Any
customer that wants high-speed IP that is not in range of the CO gets
pseudowire (about 2 miles). We split some of them into voice/data channels
using Adtran gear, and MUX others for higher bandwidth.

Customers that are in range of the CO get DSL/bonded DSL/EOC. We require one
of the latter two options for SIP.

We do our business in mostly rural areas, no fiber except to the city core.
We have leased fiber connecting our POPs for out IP backbone. We have good
QoS inside of our network, but not in the outbound long-distance trunks.
That is the reason we see more errors there, which we don't see inside our
footprint.

Once upon a time the telecom network was the heart of this company, and data
services plugged into it. Now the exact opposite is true, the IP network is
the heart, and the telecom circuits are appendages to that. The
time-tested/widely-available TDM gear is still used - at the customer's
premises, but our core network is IP-based.

Lonny Clark

On Mon, Jan 24, 2011 at 2:25 PM, Paul Timmins <paul at timmins.net> wrote:

> 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
>
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