Re: IfIndex persistance

On Wed, 16 Feb 2005 09:50:18 +0000 David wrote:
DG> It would appear that CISCO routers have a feature (1) which allows the
DG> ifindex values which are sent in SNMP responses to be persistant. [...]
DG>
DG> Is there a way to achieve this on net-snmp, or could it be added? Its not
DG> really the reboot persistance that bothers me, its the chopping and
DG> changing that happens with tunnels which come and go that causes the
DG> unnecessary traffic.

Unfortunately, this is not a simple issue. Indexes should absolutely stay the
same during the lifetime of the agent process. On some platforms it does. On
others it does not. The current trend, I think, is to get the ifIndex
information from the kernel. On some platforms, this is already true. On
others, it isn't. For example, on Linux the current default ifTable
implementation uses counting (and thus is subject to shifting indexes). The new
mfd rewrite however, gets ifIndexes from the kernel. It remains to be see if
this will be sufficient, or if some other mechanism is needed for kernels which
might re-use interface names or indexes for transitory interfaces like tunnels.

What os are you using? If you bring up a tunnel to site A, what is the
interface name? If you take that tunnel down and bring up a tunnel to site B,
does it get the same name, or a different one?

--
Robert Story; NET-SNMP Junkie
Support: <http://www.net-snmp.org/> <irc://irc.freenode.net/#net-snmp>
Archive: <http://sourceforge.net/mailarchive/forum.php?forum=net-snmp-users>

You are lost in a twisty maze of little standards, all different.


-------------------------------------------------------
SF email is sponsored by - The IT Product Guide
Read honest & candid reviews on hundreds of IT Products from real users.
Discover which products truly live up to the hype. Start reading now.
http://ads.osdn.com/?ad_id=6595&alloc_id=14396&op=click
_______________________________________________
Net-snmp-users mailing list
Net-snmp-users@lists.sourceforge.net
Please see the following page to unsubscribe or change other options:
https://lists.sourceforge.net/lists/...net-snmp-users