From owner-freebsd-hackers  Fri Jan 12 12:52:24 1996
Return-Path: owner-hackers
Received: (from root@localhost)
          by freefall.freebsd.org (8.7.3/8.7.3) id MAA05545
          for hackers-outgoing; Fri, 12 Jan 1996 12:52:24 -0800 (PST)
Received: (from dyson@localhost)
          by freefall.freebsd.org (8.7.3/8.7.3) id MAA05535
          Fri, 12 Jan 1996 12:52:19 -0800 (PST)
From: John Dyson <dyson>
Message-Id: <199601122052.MAA05535@freefall.freebsd.org>
Subject: Re: Status of ISDN drivers
To: bjj@sequent.com (Ben Jackson)
Date: Fri, 12 Jan 1996 12:52:19 -0800 (PST)
Cc: jdl@jdl.com, gjennejohn@frt.dec.com, hackers@freebsd.org
In-Reply-To: <199601122033.MAA29337@eng4.sequent.com> from "Ben Jackson" at Jan 12, 96 12:33:15 pm
X-Mailer: ELM [version 2.4 PL24]
Content-Type: text
Sender: owner-hackers@freebsd.org
Precedence: bulk

> 
> In message <199601121601.IAA18013@freefall.freebsd.org> , you wrote:
> > > > WRT getting 128kb/sec. I though the RBOCs in the States only support
> > > > 56kb/sec. per channel ? How you going to squeeze 128kb/sec. out of that ?
> > > 
> > Even in Indianapolis, we get the full 64k+64k.
> 
> My impression was that you got 56k*2 + 16k, where the 16k was for routing
> and control type information, but could be used for your data if your ISP
> was connected to the same phone switch as you.
> 
There are 2-B channels, and 1 D-channel.  The B channels are usually
circuit switched and are capable of 64K -- except for when there
are antiquated trunks between COs. The D-channel is used for signaling
and can also be used for packet data if so provisioned.  (Actually
the signaling is packet Q921/Q931.)  It is possible on some switches
to configure the B-channel to be packet swithced, but the overhead is
excessive.

John Dyson