Date: Fri, 12 Jan 1996 12:52:19 -0800 (PST) From: John Dyson <dyson> To: bjj@sequent.com (Ben Jackson) Cc: jdl@jdl.com, gjennejohn@frt.dec.com, hackers@freebsd.org Subject: Re: Status of ISDN drivers Message-ID: <199601122052.MAA05535@freefall.freebsd.org> In-Reply-To: <199601122033.MAA29337@eng4.sequent.com> from "Ben Jackson" at Jan 12, 96 12:33:15 pm
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> > 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
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