[c-nsp] Re: T1 circuits over OC3

Chris Boyd cboyd at gizmopartners.com
Fri Oct 1 10:38:07 EDT 2004

OK, going back to basics:

You have an ATM OC-3 at your location?  If so, that precludes doing 
Sonet style TDM on it, since all the payload timeslots are used for ATM 
cell transport.  You can, as others have mentioned, do CBR circuit 
emulation (CE), but you'll have to have ATM switchgear with CE 
capability in front of your router to peel the CE VCs off.

You'll also have to convince your T-1 carrier to deploy CE equipment in 
their CO to turn the T-1 loop to your customer into ATM cells.  That's 
the hard part.

You may be better off talking to your carrier to see if they can do 
something about the path that the FR-ATM PVCs take to get them better 
performance.  Or get your carrier to move you from OC-3 to OC-12 so 
that you have TDM timeslots available for T-1/DS-3 circuits.

I hope that everyone will forgive (and that mimedefang is not running) 
a small GIF attachment to help make things clearer.  If not, you can 
get it here: http://www.gizmopartners.com/ce.gif

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