NFAS

~ I've ordered four new PRIs from MCI and they need to know if I want ~ one D-channel per PRI or do I want to control all four PRIs from one ~ D-channel (with another one for backup). ~ ~ I've got plenty of channels. Are there any benefits to assigning a ~ D-channel to each PRI, or is this just wasting two channels for ~ nothing? ~

Pros of having one 4 T1 NFAS group with 2 D channels:

- you get 2 extra B channels

- it might be cheaper than 4 separate PRIs

- uses up less packet handler resource on the switch (a benefit for the telco, not for you)

Pros of having 4 separate T1 PRIs:

- any 2 or 3 T1s can go down and the remaining T1s will still work

- more flexibility for moves/adds/changes

- you could configure the different PRIs different ways (e.g. one could be for dialout only, you could have different DNIS for different service etc.)

If you don't care about the extra 2 B channels, and if the telco charges the same either way, I'd go with the 4 separate PRIs personally.

Aaron

In addition to Aaron's response, I've run into gear that doesn't do NFAS correctly, or at all. So its going to also depends on what you are hooking up, and if it properly supports NFAS.

NFAS came later, and not doing it is more well supported on different gear.

Also with some PBXs NFAS is an extra cost option.

Just my opinion, but NFAS complicates things. I believe in the KISS method. (Keep It Simple, Stupid)

If you only have 1 B channel and your lose that PRI all the other PRI's go down, too. If each PRI has it's own B channel and one goes down the others still function.

Take care, Rich

God bless the USA

- Less chance the carrier will really screw thing up....

Thank you all for your comments. I sent the provisoning guy a message that we want a D channels for each PRI.

-- Bob Simon remove both "x"s from domain for private replies