ac220@cleveland.freenet.edu (Richard Szabo) (11/17/90)
What are the alternatives to the following: My shop runs a data network over multi-drop four-wire leased lines to ~80 branch locations stragetically sprinkled over half of our state, Ohio. The lines run SDLC or Bisync and carry IBM 3270 terminal traffic. There are 4800- and 9600-bps circuits. The lines are utilized only during normal business hours. They cost a lot. Is there a good way to have switched lines dial into a bridge to create a multi-drop image? Is X.25 a viable alternative? Are there new services such as ISDN or Virtual Private Data Networks or anything else that could substitute? Rich Szabo Cleveland, Ohio, USA +1 216 662 1112 Internet: ac220@cleveland.freenet.edu
BRUCE@ccavax.camb.com (Barton F. Bruce) (11/20/90)
In article <14764@accuvax.nwu.edu>, ac220@cleveland.freenet.edu (Richard Szabo) writes: > What are the alternatives to the following: My shop runs a data > network over multi-drop four-wire leased lines to ~80 branch locations If you have DDS II filed there you should find that you can do the whole thing with digital ckts. Digital multidrop nets are what the bank cash machines and lottery agents all use. x.25 may be viable. There are IBM related issues there that I don't know about, but the LECs are installing x.25 switches (getting ready for x.25 on ISDN) and here in MA, a 9.6kb port into their x.25 switch is about $40/mo. You then need to rent some sort of channel from that CO (may be a few COs away) to you. The typical choices are: DDS II (which may include some DOV class hardware at lower speeds), DOV over an existing dialup phone line, or (yuk) even a four wire analog ckt with a v.29 modem on it. You will pay SOOO much to rent a telco v.29 for the CO end (95/mo here) that this latter one is a silly choice. If you go with DDS, look for NRS (network reconfig service) or any sorts of CO multiplexing that may be offered. The T1 that starts at one end of the state goes to some far point and then gets broken down to 24 DS0s. In NRS, you get to control and reconfigure the CO DACSs remotely. Great for testing and emergency backup site switching. With the CO muxing, they just break it up for you and it sits quite static until you pay to change something. It is possible that NEITHER is available, but ask. Is there a single or a few cable companies that cover all this area? Are many of your sites covered by the same cable headend? Are there any fiber bypass carriers making any headway? If so, the phone company should be getting more creative in providing what you have long needed.
schoff@uu.psi.com (Martin Schoffstall) (11/29/90)
In article <14868@accuvax.nwu.edu> BRUCE@ccavax.camb.com (Barton F. Bruce) writes: X-Telecom-Digest: Volume 10, Issue 837, Message 5 of 9 In article <14764@accuvax.nwu.edu>, ac220@cleveland.freenet.edu (Richard Szabo) writes: >> What are the alternatives to the following: My shop runs a data >> network over multi-drop four-wire leased lines to ~80 branch locations >If you have DDS II filed there you should find that you can do the >whole thing with digital ckts. Digital multidrop nets are what the >bank cash machines and lottery agents all use. In the NYC area many of the ATM machines use the local NYTEL X.25 network. Marty [Moderator's Note: This seems to be the case in Chicago also, at least for ATM's run by First National Bank. PAT]