From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sowmini Varadhan Subject: Re: [RFC] Stable interface index option Date: Tue, 1 Dec 2015 16:06:08 -0500 Message-ID: <20151201210608.GB23178@oracle.com> References: <20151201080652.5cba6f8b@xeon-e3> <20151201.142847.1980856920707150414.davem@davemloft.net> <20151201122038.795305df@xeon-e3> <20151201.155725.733555238839381632.davem@davemloft.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: stephen@networkplumber.org, hannes@stressinduktion.org, max@rfc2324.org, netdev@vger.kernel.org To: David Miller Return-path: Received: from aserp1040.oracle.com ([141.146.126.69]:18492 "EHLO aserp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753070AbbLAVGU (ORCPT ); Tue, 1 Dec 2015 16:06:20 -0500 Content-Disposition: inline In-Reply-To: <20151201.155725.733555238839381632.davem@davemloft.net> Sender: netdev-owner@vger.kernel.org List-ID: On (12/01/15 15:57), David Miller wrote: > >> > Also current versions of SNMP provide more useful information about > >> > network interface slot information in ifDescription > >> > >> Well if they do provide strings, then that is probably a better way > >> forward than messing with the kernel. > > > > It gives strings based on PCI information but nothing useful > > on tunnels. > > But at least in theory, that could be extended to do so right? iirc even for the cisco NOS-es, the snmp ifindex for virtual interfaces (tunnels, vpc, loopback) etc would not have any slot etc info, but would have other things (specific to the virtual interface type, e.g., FEX interface index had something that was pertinent to fex) But the bigger reason they had a immutable snmp-ifindex was that the uspace networking applications could build state based on that immutable index and hang on to that number, regardless of any renumbering that happened due to HA/failover. And, since they did not (in general) have to deal with random third party apps, they did not have to deal with questions like "what should POSIX/glibc APIs send - the immutable or the mutable index?" so it was ok for them to have the complexity of two interface indices. --Sowmini