From owner-freebsd-hackers@FreeBSD.ORG Wed Sep 12 12:39:57 2007 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 7A0E216A417 for ; Wed, 12 Sep 2007 12:39:57 +0000 (UTC) (envelope-from alexey.bobok@gmail.com) Received: from ug-out-1314.google.com (ug-out-1314.google.com [66.249.92.173]) by mx1.freebsd.org (Postfix) with ESMTP id E8FE713C45B for ; Wed, 12 Sep 2007 12:39:56 +0000 (UTC) (envelope-from alexey.bobok@gmail.com) Received: by ug-out-1314.google.com with SMTP id a2so229855ugf for ; Wed, 12 Sep 2007 05:39:56 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=beta; h=domainkey-signature:received:received:date:from:x-mailer:reply-to:x-priority:message-id:to:subject:in-reply-to:references:mime-version:content-type:content-transfer-encoding; bh=E6Ue1qkS0BB0NB8MrGM1B7OVB7JUX3n0iVrjkJ9SVtE=; b=cieD/co2zqpZYzXhXaW2HwGBU+jod1+9mDsV2NCa7iwCRTgzw7KLqCBHTXmn/PYwvA3FdeK7nqnfW0yhWwHeT7nTK6JFEe5jOjZQJfXlLLLkFjwkbLe4lqvoCdDDa0HaeUyXFHte4FevycBI26ANtR49QD8ozLsoY9gzNIp+/34= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=beta; h=received:date:from:x-mailer:reply-to:x-priority:message-id:to:subject:in-reply-to:references:mime-version:content-type:content-transfer-encoding; b=nSgDtIpNe/Rtda3eFKULOku7cxfu3CmwNHVmv5HP8ksXlnIpgjPB4i9wxAAkhM6fpO6rMPhnouTy7pG16JkE27FnmLlK2KXt89cYzH/eoKp7AuTrT8LKhGORnlSarYQJsBMlBvYEPt7avaZh6QLs5QFc1jxw776WmYhWXP21HXs= Received: by 10.67.15.17 with SMTP id s17mr1779557ugi.1189599186263; Wed, 12 Sep 2007 05:13:06 -0700 (PDT) Received: from showjumper.inetcom.com.ua ( [77.90.253.35]) by mx.google.com with ESMTPS id k30sm2721441ugc.2007.09.12.05.12.57 (version=SSLv3 cipher=OTHER); Wed, 12 Sep 2007 05:12:58 -0700 (PDT) Date: Wed, 12 Sep 2007 15:12:59 +0300 From: Alexey Bobok X-Mailer: The Bat! (v3.99.1) Professional X-Priority: 3 (Normal) Message-ID: <869014419.20070912151259@gmail.com> To: "freebsd-hackers-request@freebsd.org" In-Reply-To: <20070912120008.AB75216A477@hub.freebsd.org> References: <20070912120008.AB75216A477@hub.freebsd.org> MIME-Version: 1.0 Content-Type: text/plain; charset=windows-1251 Content-Transfer-Encoding: quoted-printable Subject: Re: freebsd-hackers Digest, Vol 233, Issue 3 X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list Reply-To: Alexey Bobok List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 12 Sep 2007 12:39:57 -0000 =C7=E4=F0=E0=E2=F1=F2=E2=F3=E9=F2=E5, freebsd-hackers-request. I think it's not real because of implementation of TCP protocol (ACK numbers and so on). Maybe it's easier to use smthng like CARP to share 1 IP between multiple hosts, PFSYNC to share state tables of PF? > Send freebsd-hackers mailing list submissions to > freebsd-hackers@freebsd.org > To subscribe or unsubscribe via the World Wide Web, visit > http://lists.freebsd.org/mailman/listinfo/freebsd-hackers > or, via email, send a message with subject or body 'help' to > freebsd-hackers-request@freebsd.org > You can reach the person managing the list at > freebsd-hackers-owner@freebsd.org > When replying, please edit your Subject line so it is more specific > than "Re: Contents of freebsd-hackers digest..." > Today's Topics: > 1. TCP/IP redundant connections (Artem Kazakov) > 2. Announcement: Devilator 1.0a for FreeBSD (Borja Marcos) > ---------------------------------------------------------------------- > Message: 1 > Date: Tue, 11 Sep 2007 23:33:19 +0900 > From: "Artem Kazakov" > Subject: TCP/IP redundant connections > To: "FreeBSD Hackers" > Message-ID: > > Content-Type: text/plain; charset=3DISO-8859-1 > Hello Everyone! > For my research project I'm working on making some network services redun= dant. > And I have one idea, but I'm not so good and operating system > internals, so could you please tell what do you think. If it is > possible at all. > So, I have two hosts, which are all the same and they have some > network service which I need to make available all the time. This > service has some internal state, which is synchronized over private > connection. And at one time only one of the servers actually works > with clients, the other on is just sitting there and kept > synchronized. > The clients have persistent TCP connections to the server, and in case > of failure they make UDP broadcasts searching for server and then > reconnect. So basically there is no need to use IP-sharing between two > of them. But if the server fails, the client usually notices that > after some time-out (tcp keep alive time out I suppose) which is not > very good in some cases. > So I want to utilize IP-sharing and TCP-connection synchronization > (which is not yet implemented by anyone as far as I know). I want it > in case of failure seamlessly to switch to the other machine. As far > as the internal state is synchronized, if it is possible to > synchronize open connections as well(and all the low level stuff as > packet sequence numbers and so on) it would allow to make switch-over > to the back-up server in a matter of seconds, and the clients would > stay connected. > Is is possible to do so ? And if yes, how difficult would it be for a > person who has solid background in general-tasks programming, but no > experience with low level system programming ? And what are the > possible cave-eats of this approach? > Thank you. > Artem Kazakov. --=20 =D1 =F3=E2=E0=E6=E5=ED=E8=E5=EC, =C0=EB=E5=EA=F1=E5=E9 =C1=EE=E1=EE=EA mailto:alexe= y.bobok@gmail.com