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<big>Greg,<br>
<br>
My assumption from your discussion is that you are transporting ATM
cell traffic over T1 circuits. If you are transporting T1 TDM traffic
over ATM than<br>
that is a different matter. T1 over ATM cells need to be terminated and
have the ATM cells stripped reconstruct the ESF frame of T1 and then
you can run<br>
it over "standard" T1/DS3/T3 infrastructure. <br>
<br>
Having done ATM over T1 in a previous life, usually the framing for an
ATM T1 is ESF. As long as you are muxing on a straight 28 T1's on a
T3/DS3 over fiber or that keeps channelized T1s for your ATM circuits
you are fine. SBC and Verizon both have tarriffed services for ATM over
T1, T3, OC-3c and OC12c the last time I worked with them. If memory
serves We used HEC encoding on the DS3 based ATM circuits but for
standard M13 mux i do not know if it will be C, hec or PLCP encoding.<br>
<br>
What is the payload that you are transporting over the ATM cells? TDM
traffic such as voice, IP over ATM, IP over Frame Over ATM, video over
ATM<br>
or native ATM cells? You will get some additional propagation delay and
jitter whether you just transport the bits or terminate the circuits
and forward the<br>
data streams or PDUs.<br>
<br>
One issue that I would research on the device that you are terminating
the T1 with ATM payload into is whether the interface uses the ESF
signalling channel<br>
at all?<br>
<br>
John Lee<br>
(ISDN - It Suites Dennis's Needs)<br>
</big><br>
<br>
<br>
Greg Boehnlein wrote:<br>
<blockquote type="cite"
cite="midPine.LNX.4.44.0412011328160.23652-100000@nucleus.nacs.net">
<pre wrap="">Hello,
This is my first post to the NANOG list, so please.. be gentle! ;)
I am looking at consolidating several different POPs in a specific city
that include a mixture of Point to Point and ATM T1 circuits. My goal is
to shut down all of the physical infrastructure in that city, cross
connecting all of the circuits onto a Muxed DS3 and backhaul them into a
larger Metro POP.
This is pretty simple for the standard DS1 and PRI circuits, but
the ATM T1 connections have me wondering. I do not have a great deal of
experience with ATM, and although we have a couple of T1 ATM
interconnetions in our primary Metro POP, I am questioning wether it is
truly possible to cross connect the ATM T1 interconnects to Verizon and
SBC onto a standard M13T mux, backhaul them into my Metro POP and then
hand them off to appropriate ATM interfaces.
I've gotten conflicting answers from various sources, so I figured
that I would ask here, as most likely there is someone here who can give a
cogent answer as to why or why not.
So, can I cross connect several ATM T1s onto a DS3 mux and break them out
on the other side? Or do I need some sort of intelligent MUX that
understands ATM?
</pre>
</blockquote>
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