Path: utzoo!attcan!uunet!altnet!ernie!peter
From: peter@ernie.NECAM.COM (Peter DiPrete)
Newsgroups: comp.dcom.lans
Subject: Re: Ethernet bridges above 56Kb
Summary: Yes, you can use parts of a T1 curcuit
Message-ID: <116@ernie.NECAM.COM>
Date: 22 Jul 88 02:47:17 GMT
References: <9392@dartvax.Dartmouth.EDU>
Organization: NEC America RATS, San Jose, CA
Lines: 29

In article <9392@dartvax.Dartmouth.EDU>, finn@eleazar.dartmouth.edu (Andy Behrens) writes:
> 
> All the bridges that I have seen either use an entire T1 circuit, or
> use only 56Kb of it.  Does anyone know of one which can be configured
> for data rates between these limits?

This question requires a little knowledge about how 56 Kb circuits and T1
circuits (actually called facilities) are related.  A T1 (sometimes called
DS1) facility is composed of 24 multiplexed 56 Kb (called T0 or DS0) circuits.
If your application will use less than half of the T1 facility, you might 
consider a T1 mux and use as many T0 circuits out of the 24 that you feel
you require for the particular application.

Of course, the additional hardware costs money, and there may be better ways
to use the bandwidth.  Bridge communications, now part of 3Com, has a wide
variety of products that will allow you to bring 56 Kb INTO the LAN you 
are shipping via the T1 line and share it that way.  And since the Bridge
boxes are effectively "packet switches," this might make the MOST effective
use of the lan.  It would also let you attach PC's and other equipment to the
lan and share them long distance.

We are looking at Bridge IB/3's to connect three LANs, one in Japan, one in
Virginia, and one in San Jose!  I'll let you all know how it works out.

Peter Di Prete
NEC America
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