[c-nsp] bonded T1s into 7206VXR

[Bill Wichers]

> Hi all,
[snip]
> My question is: will this bonded T1 service act like a single circuit?
> I.e.
> if I have a single TCP connection that needs, say 4M bandwidth, will the
> bandwidth be equally distributed across all three 1.5M circuits?

Yes, it will have the bandwidth of 3xT1 circuits, but latency will be the
same as a single T1 circuit. You can get the full bandwidth using ATM
bonding or MLPPP, and I would bet ATT will use one of those two methods to
deliver the service.

> I am also
> wondering if the bonding will work any differently if the (3) T1's are
> across (2) PA-MC-2T1 cards vs a single PA-MC-4T1 card.

I don't think it will matter in a 7200 how the ports are distributed
card-wise (in a 7500 it can matter with dCEF and such). For simplicity,
I'd personally use a PA-MC-4T1 card and put all the members of the 4.5
Mb/s T1 bundle into the same card. That way all your circuits are on
interfaces in order which is a lot easier for management purposes, IMHO. I
also *know* that works with MLPPP :-)

If ATT uses ATM bonding to deliver the service, then you'll probably have
to use one card since the ATM is handled in hardware and I don't think it
can span multiple port adapters.

You should ask ATT if they will use MLPPP or ATM bonding to bond the T1s
together into a bundle, since that will have a big impact on what you'll
need in your router to support the connection.

     -Bill

*****************************
Waveform Technology
UNIX Systems Administrator