Date: Mon, 19 Apr 2004 15:43:30 -0700 From: Bill Fumerola <billf@FreeBSD.org> To: Julian Elischer <julian@elischer.org> Cc: net@freebsd.org Subject: Re: what is the story on if_index allocation ? Message-ID: <20040419224330.GN17862@elvis.mu.org> In-Reply-To: <Pine.BSF.4.21.0404191227150.64627-100000@InterJet.elischer.org> References: <20040419110912.A71274@xorpc.icir.org> <Pine.BSF.4.21.0404191227150.64627-100000@InterJet.elischer.org>
next in thread | previous in thread | raw e-mail | index | archive | help
On Mon, Apr 19, 2004 at 12:28:23PM -0700, Julian Elischer wrote:
> It's completely un-needed except that some standards want to access
> interfaces by index for statitics purposes.
they're "un-needed" in much the same way that statically assigning disk
numbers is "un-needed". sure, the disks don't light on fire without it,
but some consistancy and persistance does make things nice.
for comparison: vendor C has a default-to-off option for this (''snmp
ifindex persist'') which pre-allocates numbers loosely based on max_modules
* max_ports_in_modules and dumps this mapping into the filesystem. vendor
J allocates dynamically and won't reuse ifIndex numbers over the life
of a router.
a way of keeping indexes consistant for a given named interface (even
across creation/destruction via cloning, kld, etc) is most certainly a
desirable feature. the more persistant this can be made (life of the
module all the way up to life of device) the better.
i disagree that this logic belongs outside the kernel in the snmp agent.
an inconsistant if_index makes it difficult and error prone for using
the index in multiple utilities whose data may be combined/joined/scaled
with information from the snmp agent's IF-MIB/ifXTable tables.
--
- bill fumerola / fumerola@yahoo-inc.com / billf@FreeBSD.org
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20040419224330.GN17862>