From owner-freebsd-net@FreeBSD.ORG Thu Dec 7 12:12:04 2006 Return-Path: X-Original-To: freebsd-net@freebsd.org Delivered-To: freebsd-net@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id 2FB9916A510; Thu, 7 Dec 2006 12:12:04 +0000 (UTC) (envelope-from rrs@cisco.com) Received: from sj-iport-4.cisco.com (sj-iport-4.cisco.com [171.68.10.86]) by mx1.FreeBSD.org (Postfix) with ESMTP id 1F1B643D62; Thu, 7 Dec 2006 12:07:12 +0000 (GMT) (envelope-from rrs@cisco.com) Received: from sj-dkim-8.cisco.com ([171.68.10.93]) by sj-iport-4.cisco.com with ESMTP; 07 Dec 2006 04:08:03 -0800 Received: from sj-core-3.cisco.com (sj-core-3.cisco.com [171.68.223.137]) by sj-dkim-8.cisco.com (8.12.11/8.12.11) with ESMTP id kB7C830v021703; Thu, 7 Dec 2006 04:08:03 -0800 Received: from xbh-sjc-221.amer.cisco.com (xbh-sjc-221.cisco.com [128.107.191.63]) by sj-core-3.cisco.com (8.12.10/8.12.6) with ESMTP id kB7C82dE001884; Thu, 7 Dec 2006 04:08:03 -0800 (PST) Received: from xfe-sjc-212.amer.cisco.com ([171.70.151.187]) by xbh-sjc-221.amer.cisco.com with Microsoft SMTPSVC(6.0.3790.1830); Thu, 7 Dec 2006 04:08:02 -0800 Received: from [127.0.0.1] ([171.68.225.134]) by xfe-sjc-212.amer.cisco.com with Microsoft SMTPSVC(6.0.3790.1830); Thu, 7 Dec 2006 04:08:02 -0800 Message-ID: <457803F1.7040303@cisco.com> Date: Thu, 07 Dec 2006 07:07:13 -0500 From: Randall Stewart User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.7.12) Gecko/20050920 X-Accept-Language: en-us, en MIME-Version: 1.0 To: Andre Oppermann References: <161d69110612060709n3bf99bd4y47d94b021b8f1d02@mail.gmail.com> <4577D858.4010300@freebsd.org> In-Reply-To: <4577D858.4010300@freebsd.org> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit X-OriginalArrivalTime: 07 Dec 2006 12:08:02.0221 (UTC) FILETIME=[57FE35D0:01C719F8] DKIM-Signature: v=0.5; a=rsa-sha256; q=dns/txt; l=915; t=1165493283; x=1166357283; c=relaxed/relaxed; s=sjdkim8002; h=Content-Type:From:Subject:Content-Transfer-Encoding:MIME-Version; d=cisco.com; i=rrs@cisco.com; z=From:=20Randall=20Stewart=20 |Subject:=20Re=3A=20Urel, =20a=20TCP=20option=20for=20Unreliable=20Streami ng.=20Need=20your=20help. |Sender:=20; bh=juSQEwmjzHzAmlLHhVy+AtJ8l5TYZ7oABcBWVWT+JuI=; b=USFg3mdlUz8QzJ1DKVCXZ8gGxZ6IMosVYhb+84t9OQBeyFuz03gRf318X98LhaBeL9HxwT3U pqIBiBqpnUAfEsSatryC+QhQoYEdjmB1cKzuTkJ4DZ6iC4Pw8URg9KJe; Authentication-Results: sj-dkim-8; header.From=rrs@cisco.com; dkim=pass (sig from cisco.com/sjdkim8002 verified; ); Cc: gnn@freebsd.org, maillist ifiaas , freebsd-net@freebsd.org Subject: Re: Urel, a TCP option for Unreliable Streaming. Need your help. X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 07 Dec 2006 12:12:04 -0000 Andre Oppermann wrote: > gnn@freebsd.org wrote: > > >> >> How is this different from the recently integrated SCTP? > > > It doesn't try to retransmit at all. A lost segment is lost and > resending it would be pointless for realtime content. On the other > hand you don't want to blast the network at a fixed rate and so > this protocol wants to use a congestion control algorithm to back > off when bandwidth gets scarce. I haven't looked at the details > yet but my initial guess would be that the actual TCP code isn't > the best starting point. TCP is too obsessed with retransmitting > if something got lost. > Andre: Thats true for normal SCTP.. not PR-SCTP.. which is a sender option. In this case you don't get retransmissions.. or get a limited number depending on how you set it up :-) R -- Randall Stewart NSSTG - Cisco Systems Inc. 803-345-0369 803-317-4952 (cell)