From owner-freebsd-isdn Fri Oct 26 5:33:14 2001 Delivered-To: freebsd-isdn@freebsd.org Received: from arg1.demon.co.uk (arg1.demon.co.uk [194.222.34.166]) by hub.freebsd.org (Postfix) with ESMTP id B5D7F37B405 for ; Fri, 26 Oct 2001 05:33:12 -0700 (PDT) Received: by arg1.demon.co.uk (Postfix, from userid 1002) id 2B16C9B1A; Fri, 26 Oct 2001 13:33:11 +0100 (BST) Received: from localhost (localhost [127.0.0.1]) by arg1.demon.co.uk (Postfix) with ESMTP id 225EC5D24; Fri, 26 Oct 2001 13:33:11 +0100 (BST) Date: Fri, 26 Oct 2001 13:33:11 +0100 (BST) From: Andrew Gordon X-X-Sender: To: Martin Husemann Cc: Subject: Re: RFC1974 (STAC) In-Reply-To: <200110260716.f9Q7Gju04711@night-porter.duskware.de> Message-ID: <20011026132510.N36971-100000@server.arg.sj.co.uk> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-freebsd-isdn@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.org On Fri, 26 Oct 2001, Martin Husemann wrote: > Excuse me if I'm a bit behind with reality (in catch-up mode now) - I just > noticed one of the big german ISPs, t-online, now offers STAC compression > (RFC 1974) for their ISDN access. Do we have support for that already? Anyone > looked at it? I don't know of implementation for use with I4B. The information necessary to implement it is publicly available - RFC1974 gives the PPP packet encapsulation, and the compression algorithm itself is in X3.241, available from ANSI (it's only 14 pages). There appears to be a linux implementation (I've not tried it): http://www.ibh.de/~beck/stuff/lzs4i4l/ However, STAC holds patents on the compression algorithm, so the legal status of any implementation would be questionable. It is also not clear that it offers much advantage in typical use, since many things are already compressed (graphics on web pages, .tgz downloads, SSH tunnels/connections), and small transfers are constrained by TCP slow-start (the acutal HTML of sensible size web pages). I suppose compression would help with those web pages which have stupid amounts of javascript with long variable names and loads of whitespace. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-isdn" in the body of the message