From owner-svn-src-head@freebsd.org Thu Jan 4 20:16:41 2018 Return-Path: Delivered-To: svn-src-head@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 85A9DEB3D68; Thu, 4 Jan 2018 20:16:41 +0000 (UTC) (envelope-from lidl@pix.net) Received: from hydra.pix.net (hydra.pix.net [IPv6:2001:470:e254:10::4]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client CN "mail.pix.net", Issuer "Pix.Com Technologies LLC CA" (not verified)) by mx1.freebsd.org (Postfix) with ESMTPS id 8F3F17EF3E; Thu, 4 Jan 2018 20:16:40 +0000 (UTC) (envelope-from lidl@pix.net) Received: from torb.pix.net ([IPv6:2001:470:e254:11:146e:bd77:a3bd:67b7]) (authenticated bits=0) by hydra.pix.net (8.15.2/8.15.2) with ESMTPA id w04KGNag084945; Thu, 4 Jan 2018 15:16:30 -0500 (EST) (envelope-from lidl@pix.net) X-Authentication-Warning: hydra.pix.net: Host [IPv6:2001:470:e254:11:146e:bd77:a3bd:67b7] claimed to be torb.pix.net Subject: Re: svn commit: r327086 - head/sys/dev/lmc To: Poul-Henning Kamp , Stefan Esser Cc: Pedro Giffuni , Warner Losh , Brooks Davis , svn-src-head@freebsd.org, svn-src-all@freebsd.org, src-committers References: <201712221715.vBMHF27m046894@repo.freebsd.org> <20180103220942.GC95035@spindle.one-eyed-alien.net> <02a7407a-0445-e503-9279-e893f53f8ef0@FreeBSD.org> <3f4a7247-e711-c65a-d973-c929ac8726db@freebsd.org> <62258.1515060043@critter.freebsd.dk> From: Kurt Lidl Message-ID: Date: Thu, 4 Jan 2018 15:16:23 -0500 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.12; rv:52.0) Gecko/20100101 Thunderbird/52.5.2 MIME-Version: 1.0 In-Reply-To: <62258.1515060043@critter.freebsd.dk> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-BeenThere: svn-src-head@freebsd.org X-Mailman-Version: 2.1.25 Precedence: list List-Id: SVN commit messages for the src tree for head/-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 04 Jan 2018 20:16:41 -0000 On 1/4/18 5:00 AM, Poul-Henning Kamp wrote: > -------- > In message <3f4a7247-e711-c65a-d973-c929ac8726db@freebsd.org>, Stefan Esser writes: >> Am 04.01.18 um 00:41 schrieb Pedro Giffuni: > >> It appears to be a strange beast that uses the Ethernet chip to generate a >> bit stream which is then converted to HDLC. Not sure whether these were used >> for Frame Relay or to connect to the British X.25 JANET, a few decades ago. >> Perhaps also to connect to SS7 signaling networks? > > They were actually pretty versatile, we used them both for "blank" > E1 and Nx64 scenarios, and I know they were used for Frame Relay > several places in US. > > I don't think they could do SS7 or ISDN like the MUSYCC chip could. > > But nobody uses T1/E1/T3/E3 lines any more for anything... There's thousands upon thousands of customers that attach to networks via T1 lines, running Frame-Relay to this day. Granted, ADSL has captured the consumer market, but NxT1 is still popular in the business world. (And pretty much all the T1s in the world are actually delivered over 2Mmbps SDSL, which is then turned into the 1.544 mbps T1 interface, but that's not really germane to this...) As for the lmc product itself, and that driver- David Boggs, when working at DEC-WRL (Dec's Western Research Lab) realized that the Ethernet controller that ran the "de" Ethernet chips could be easily plumbed into an FPGA and used as the front-end controller for the framer for the serial line. In 1999 I worked with David Boggs to modernize this driver (or more precisely, the "sbe" version of it), so it had SMP locking for FreeBSD and BSD/OS. Dave is really easy to work with, and we were able to make the driver deal with Frame Relay, in addition to the "Cisco HDLC" (aka chdlc) framing. I don't think we attempted to get the synch PPP stuff working, as I only had access to a T1 line with FR signaling on it. T1 is just an electrical standard for interface, you can do all sorts of different signaling and protocols over that interface. I still have this hardware (but not in use), as well as a pair of the HSSI boards (54mbps, suitable for use with a T3 circuit). If you just want someone to test it, I can probably lash together two machines with these cards as the interconnect. -Kurt