Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Fri, 1 Nov 2002 19:27:07 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Fri, 1 Nov 2002 19:27:07 -0500 Received: from e4.ny.us.ibm.com ([32.97.182.104]:65202 "EHLO e4.ny.us.ibm.com") by vger.kernel.org with ESMTP id ; Fri, 1 Nov 2002 19:27:05 -0500 From: "Venkata Jagana" Importance: Normal Sensitivity: Subject: Re: [PATCHSET] Mobile IPv6 for 2.5.45 To: "David S. Miller" Cc: yoshfuji@wide.ad.jp, kkumar@beaverton.ibm.com, kuznet@ms2.inr.ac.ru, ajtuomin@tml.hut.fi, lpetande@tml.hut.fi, netdev@oss.sgi.com, linux-kernel@vger.kernel.org X-Mailer: Lotus Notes Release 5.0.3 (Intl) 21 March 2000 Message-ID: Date: Fri, 1 Nov 2002 16:32:13 -0800 X-MIMETrack: Serialize by Router on D03NM036/03/M/IBM(Release 5.0.10 |March 22, 2002) at 11/01/2002 05:32:21 PM MIME-Version: 1.0 Content-type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1890 Lines: 47 Hello Dave, >Just like a router changes and monitors routes, a home agent daemon >would change and monitor mipv6 state. So for the same reason we don't >put OSPF routing databases into the kernel, we do not put the home >agent registration into the kernel :-) I absolutely understand your concerns about keeping the Home Agent registration in the kernel. However, I still believe that keeping this code in userspace would cause problems for handoffs. (btw, this code will never get executed on a regular host - only routers configured as Home Agents would be running this code as a module). Currently, when a Home Agent receives a registration request during the Mobile Node's handoff mechanism, it needs to respond in a reasonably quick time period so that the sessions on the MN can continue without experiencing delays. Longer delays could be harmful for applications such as VoIP, for which the latencies are quite critical. By moving this registration process to userspace, we have no control over when the home registration would complete, since there are no guarantees when the home agent daemon would run. BTW, according to ongoing discussions at Mobile IP WG, it is believed that even few hundred millisecs of latencies are not acceptable to critical apps, during which time the IP packet transfer is completely stopped. With such latency issues, I still believe that moving the registration to userspace would create issues for the MN. Thanks, Venkat ---------------------------------------------------------------- Venkata R Jagana IBM Linux Technology Centre, Beaverton jagana@us.ibm.com Tel: (503) 578 3430 T/L 775-3430 - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/