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From: motcid!benyukhi@uunet.uu.net (Ed Benyukhis)
Newsgroups: comp.dcom.telecom
Subject: Re: ISDN Frame Relay Service
Message-ID: <14615@accuvax.nwu.edu>
Date: 9 Nov 90 14:29:48 GMT
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X-Telecom-Digest: Volume 10, Issue 813, Message 8 of 8


In article <14396@accuvax.nwu.edu>, zweig@cs.uiuc.edu (Johnny Zweig)
writes:

> I was talking to Van Jacobson last week and he described a service his
> local telco is going to offer real soon now in which the customer sets
> up virtual calls using the D-channel and then dumps HDLC frames onto
> the B-channel and they get routed by the CO switch. Zounds! This
> sounds really neat -- the functionality of IP coming right out of the
> funny-looking ISDN jack on the wall.  

> Does anyone know more about this service?  I am mostly interested in
> how reliable the frame delivery would be, whether frames would be
> delivered in order, whether one could set up calls to the same
> destination over both B-channels in a PRI (to crank out 128kbps to a

> single other machine) and that sort of thing.

The way you describe the connection and looking at the data transfer
rate, you are referring to a BRI and not a PRI.  The subject, of your
post semms to suggest that you want to know more about Broadband ISDN
services and recomendation.  Frame Relay Service is really an OC-1
CCITT standard that is being implemented with laboratory equipment and
in laboratory conditions at this point.  If it is a BRI that you want
know about, as it is currently implemented on some CO switches, here
it is:

B-channel connection can be provisioned with either packet or circuit
services or both on-demand (ODB).  All connections over the B-channel
are set-up via D-channel Q.931 control messages.  However, in the case
of a circuit switched connection, layers 2-7 are not defined nor used.
Users can/should provide their own synchronization and error control
mechanisms.  In the case of the Packet Switching over the B-channel,
layer 2 is LAPB and layer 3 is X.25.  You get your basic synch, error
correction and the flow control with these two layers.  Yes, PVC
guarantees that frames will be delivered in order, and yes, both
B-channesl can be routed to the same destination address.

I am not really sure if this is what you are looking for of if it is
different ISDN services you are interested in.  Drop me a line if you
want to find out more about ISDN or BISDN.

Regards,

Edward Benyukhis, Motorola, CIG
(708) 632-4658