From owner-freebsd-net@FreeBSD.ORG Mon Aug 8 15:58:58 2005 Return-Path: X-Original-To: freebsd-net@freebsd.org Delivered-To: freebsd-net@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id BF39D16A41F; Mon, 8 Aug 2005 15:58:58 +0000 (GMT) (envelope-from zec@icir.org) Received: from xaqua.tel.fer.hr (xaqua.tel.fer.hr [161.53.19.25]) by mx1.FreeBSD.org (Postfix) with ESMTP id 4908F43D48; Mon, 8 Aug 2005 15:58:58 +0000 (GMT) (envelope-from zec@icir.org) Received: by xaqua.tel.fer.hr (Postfix, from userid 20006) id E7C669B6C4; Mon, 8 Aug 2005 18:00:44 +0200 (CEST) Received: from [127.0.0.1] (imunes.tel.fer.hr [161.53.19.8]) by xaqua.tel.fer.hr (Postfix) with ESMTP id 54EB39B762; Mon, 8 Aug 2005 18:00:35 +0200 (CEST) From: Marko Zec To: freebsd-net@freebsd.org Date: Mon, 8 Aug 2005 17:57:47 +0200 User-Agent: KMail/1.7.2 References: <1123040973.95445.TMDA@seddon.ca> <1123055951.16791.TMDA@seddon.ca> <42F734D0.6F7387E0@freebsd.org> In-Reply-To: <42F734D0.6F7387E0@freebsd.org> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-2" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200508081757.47499.zec@icir.org> X-Spam-Checker-Version: SpamAssassin 3.0.2 (2004-11-16) on xaqua.tel.fer.hr X-Spam-Level: X-Spam-Status: No, score=-2.6 required=8.0 tests=BAYES_00 autolearn=ham version=3.0.2 Cc: Dave+Seddon , Andre Oppermann Subject: Re: running out of mbufs? 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: Mon, 08 Aug 2005 15:58:58 -0000 On Monday 08 August 2005 12:32, Andre Oppermann wrote: > Dave+Seddon wrote: > > BTW, I'd be interested to know people's thoughts on multiple IP > > stacks on FreeBSD. It would be really cool to be able to give a > > jail it's own IP stack bound to a VLAN interface. It could then be > > like a VRF on Cisco. > > There is a patch doing that for FreeBSD 4.x. However while > interesting it is not the way to go. You don't want to have multiple > parallel stacks but just multiple routing tables and interface groups > one per jail. This gives you the same functionality as Cisco VRF but > is far less intrusive to the kernel. Andre, the stack virtualization framework for 4.x is based precisely on introducing multiple routing tables and interface groups. In order to cleanly implement support for multiple independent interface groups, one has to touch both the link and network layers, not forgetting the ARP stuff... and in no time you have ended up with a huge and intrusive diff against the original network stack code. So I see no point in pretending we could get such a functionality for free, i.e. with only a negligible intrusiveness to the kernel code. A more appropriate question would be whether the potential benefits of having multiple stack state instances could outweight the trouble and damage associated with the scope of required modifications to the kernel code tree. Only if we could get an affirmative answer to that question it would make sense to start thinking / debating on the most appropriate methodology to (re)implement the multiple stacks framework. Cheers, Marko