Path: utzoo!telecom-request Date: 20 May 91 17:31:47 GMT From: "Fred R. Goldstein" Newsgroups: comp.dcom.telecom Subject: Re: It Still Don't Network ... or? Message-ID: Organization: Digital Equipment Corp., Littleton MA USA Sender: Telecom@eecs.nwu.edu Approved: Telecom@eecs.nwu.edu X-Submissions-To: telecom@eecs.nwu.edu X-Administrivia-To: telecom-request@eecs.nwu.edu X-Telecom-Digest: Volume 11, Issue 380, Message 5 of 10 Lines: 54 In article , hpa@casbah.acns.nwu.edu (H. Peter Anvin) writes... > A few questions about ISDN: > 1. Is is feasible/not feasible to use ISDN as a link in an IP or Ethernet > network? Sure. There's even an Internet mailing list on the topic of IP over ISDN. Ethernet, on the other hand, is a LAN subnet, and ISDN is a WAN subnet, so you're comparing apples to pie there. You could however run Ethernet remote bridges over ISDN. Or anything else, since it's a bit pipe. > 2. Is ISDN a worldwide standard, or another one of them "we decide what we > want" USA standards? Worldwide. CCITT I-series, to be specific, albeit with national standards for some of the finer details. > 3. Does the 64 kbit/s B-channel rate over ISDN include error correction? In circuit mode, no, it's raw bits. You run the error correction. In packet mode, it's like X.25, with a checksum on each packet. > 4. Does the D-channel protocol include service identification (say IP, > video, voice, modem)...? Generally, yes. It has specific codepoints for CCITT and ISO standard protocols at various layers. IP, on the other hand, is not CCITT-standard, so it'll probably be a) unidentified or b) identified using the "user specified" codespace. > 5. Is is possible to call a POTS line with a modem from an ISDN connection? Yes, if you run a modem over ISDN. ISDN is essentially an access arrangement, and it interworks fine with the analog phone world. > 6. What are typical rates for ISDN? Is it billed per minute or per block? Up to your local telco. Figure that circuit mode ISDN is billed like a phone call, maybe a surcharge for clear-channel data calls (but regular price for voice calls). Packet mode will probably have the usual per-packet (X.25-style) rates. Plus monthly line charges, usually between one and two times the usual phone rate, for the Basic Rate (2B+D) ISDN line. Fred R. Goldstein Digital Equipment Corp., Littleton MA goldstein@delni.enet.dec.com voice: +1 508 952 3274 Do you think anyone else on the planet would share my opinions, let alone a multi-billion dollar corporation?