From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Luis Carlos Cobo" Subject: Re: Proposed interface for per-packet mesh-ttl Date: Thu, 16 Aug 2007 15:43:16 -0700 Message-ID: <8e8340660708161543l1b4de41at861fbb98463f39e8@mail.gmail.com> References: <445f43ac0707031149o2b50fc0en48aef4130b4b60ec@mail.gmail.com> <445f43ac0707031229m4ed60e0cg7960437c3e373c8e@mail.gmail.com> <20070727195616.GA31510@infradead.org> <1185574942.17934.9.camel@xo-13-A4-25.localdomain> <20070728073145.57155e03@oldman> <445f43ac0707301337l2f7d62ebx6955a12cd89c6bd3@mail.gmail.com> <20070730215316.5c236e18@oldman> <8e8340660708161221t1c0bee01g9d0cb1835f7026f0@mail.gmail.com> <20070816171913.2ad87e47@oldman> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: "Javier Cardona" , "Dan Williams" , "Christoph Hellwig" , netdev@vger.kernel.org To: "Stephen Hemminger" Return-path: Received: from py-out-1112.google.com ([64.233.166.183]:63545 "EHLO py-out-1112.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752075AbXHPWnS (ORCPT ); Thu, 16 Aug 2007 18:43:18 -0400 Received: by py-out-1112.google.com with SMTP id u77so608551pyb for ; Thu, 16 Aug 2007 15:43:17 -0700 (PDT) In-Reply-To: <20070816171913.2ad87e47@oldman> Content-Disposition: inline Sender: netdev-owner@vger.kernel.org List-Id: netdev.vger.kernel.org On 8/16/07, Stephen Hemminger wrote: > The problem with socket options is how does the application know > the correct policy? Pushing configuration to application is just deferring > the problem, not solving it. You want some policy to be done by the > infrastructure; that means kernel, libraries, daemons, etc. Doing it in > the application is often inflexible and unusable. The policy will usually be done by the kernel. If the flag is not set, which will happen most of the time, the driver will use a sensible default ttl. The socket option would only be used by applications that are specifically interested in a configurable ttl (like an application to plot neighbors within an specific diameter). A per-interface setting is not good enough, since we do not want the neighbor-plotting tool to affect the ttl of other connections (e.g. a ssh session) that might be going on at the same time. -- Luis Carlos Cobo Rus GnuPG ID: 44019B60 cozybit Inc.