Hi,
>________________________________ > From: Fernando Gont <ferna...@gont.com.ar> >To: Brian Haberman <br...@innovationslab.net> >Cc: 6man Chairs <6man-cha...@tools.ietf.org>; Fernando Gont ><fg...@si6networks.com>; 6man WG <ipv6@ietf.org>; >draft-ietf-6man-stable-privacy-addres...@tools.ietf.org >Sent: Thursday, 11 April 2013 5:28 PM >Subject: Re: AD Evaluation: draft-ietf-6man-stable-privacy-addresses > > >Hi, Brian, > >On 04/10/2013 07:01 PM, Brian Haberman wrote: >>>> Additionally, I will note that this scenario may not be as unusual as >>>> you think. For example, the ifIndex on some Cisco gear will change >>>> enough that IOS has a configuration command to make it stable. >>> >>> what's the "event" upon which the interface index will change? >>> "Interface removal", as in the suggested text, or something else? >> >> My understanding is that some devices assign an ifIndex when the device >> is activated (e.g., at boot time). Since device activation is >> non-deterministic, an interface can get assigned a different ifIndex >> each time it boots. To deal with this behavior, IOS has a "persist" >> command that keeps state about each interfaces initial ifIndex. > >I've not experienced that myself. That said, I'd probably argue that >such changes are probably annoying for there reasons: I guess that if >the interface index changes, so does the usual suffix in the interface >name (e.g. ethN, wlanN) -- hence delaying with link-local addresses >would become more painful than necessary. > > >A number of years ago this happened with Linux. IIRC, it was related to >changing the default order of device driver loading, or changing from >sequential loading of device drivers to parallel loading. That reordered the >interface numbering and therefore the names, which people didn't like. The >solution at the time was to use the interface MAC address to assign interfaces >persistent names by renaming the interfaces late in the initialisation stage. >I don't remember reference to resetting ifindexes. > > >One thing that may also influence this draft is that interfaces may be added >to the system after it has booted. For example, I carry around a couple of >USB/Ethernet adaptors that I'll add to my laptop if I need them for >troubleshooting (and with my new laptop being wifi only, just to connect to a >wired network), and I may not know if I'll need them when I boot my laptop. I >also have a 3G mobile dongle that I occasionally use. I'm pretty sure Linux >allocates ifindex values sequentially as the driver is loaded, so what ifindex >values these dynamic interfaces gets is not going to be consistent and >persistent. > >Regards, >Mark. -------------------------------------------------------------------- IETF IPv6 working group mailing list ipv6@ietf.org Administrative Requests: https://www.ietf.org/mailman/listinfo/ipv6 --------------------------------------------------------------------
