Path: utzoo!attcan!uunet!zaphod.mps.ohio-state.edu!usc!apple!bionet!hayes.ims.alaska.edu!accuvax.nwu.edu!nucsrl!telecom-request From: ames!ames!claris!portal!cup.portal.com!fleming@uunet.uu.net Newsgroups: comp.dcom.telecom Subject: Re: ISDN Frame Relay Service Message-ID: <14446@accuvax.nwu.edu> Date: 7 Nov 90 17:04:54 GMT Sender: news@accuvax.nwu.edu Organization: TELECOM Digest Lines: 33 Approved: Telecom@eecs.nwu.edu X-Submissions-To: telecom@eecs.nwu.edu X-Administrivia-To: telecom-request@eecs.nwu.edu X-Telecom-Digest: Volume 10, Issue 797, Message 6 of 10 > 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. Frame delivery would be unreliable by design. Error-checking and retransmission becomes the responsibility of the terminal (Application Layer), not the network. This mindset change lets you rip out most of the overhead associated with X.25 and start packetizing at 1.5 Mb/s (today ... faster soon). Frames would maintain sequence since you are setting up virtual circuits (connection-oriented). "Both B channels in a PRI" -- a PRI has 23 B channels. And yes, you can dedicate all 23 of them to a single virtual circuit. I haven't seen frame relay promised yet for BRI (2B+D), but it is certainly feasible. There's a decent non-technical tutorial on frame relay in the October issue of Telecommunications magazine (Disclaimer: I wrote it). Let me know by E-mail if I can help. Stephen Fleming | Internet: fleming@cup.portal.com Director, Technology Mktg. | CI$: 76354,3176 AOL: SFleming Northern Telecom | BIX: srfleming X.500: ??? 7900 Westpark Drive, A220 +---------------------------------- McLean, Virginia 22102 | Opinions expressed do not (703) 847-8186 | represent Northern Telecom.