[c-nsp] Re: T1 circuits over OC3

Andy Dills andy at xecu.net
Fri Oct 1 12:09:03 EDT 2004

On Fri, 1 Oct 2004, Jay Ford wrote:

> On Fri, 1 Oct 2004, Andy Dills wrote:
> > I don't think they wanted to use an ATM T1, as nobody wants the cell loss
> > on low speed links like that. And few people have that type of CPE
> > equipment laying around.
> I'm not talking about ATM on T1.  I'm talking about T1 on ATM.  The CPE
> interface is plain old T1 at both ends.

I understand what you're saying now, but in order to do that, we come back
to the same problem: The telco will not just install and use the equipment
you tell them to.

We keep coming back to the same range of possibilities:

- ATM DS1 (yuck)
- Frame DS1 and FRASI
- Getting the telco to deploy equipment just for you

> > See, I thought the requirement was for terminating a traditional leased
> > line, for instance using HDLC or PPP, but just accepting the T1 over the
> > ATM.  Similar to a channelized DS3.
> Yeah, I wasn't figuring delivering the T1 at the edges via ATM, just over ATM
> in the cloud.
> > That's L1, I'm talking L2.
> The upper layers are whatever you want.  It looks like a real T1 to the gear
> at the edges.

Yes, provided you have an LS at each end. I was under the impression we
were trying to work with a scenario where neither the telco would need to
install new equipment and where the customer wouldn't need to implement
additional router ports.

And in that scenario, FRASI is the way to go. It's a shame it doesn't work
better for him, it works flawlessly for us.


Andy Dills
Xecunet, Inc.

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