Re: IfIndex persistance

On Wednesday 16 February 2005 20:40, Robert Story wrote:
> 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?

I am using linux (2.6). Its not just the tunnels, eth? and wlan? ports seem
to jump around all over the place, sometimes given numbers way above
the number of interfaces. The tunnels are tun?.

David


-------------------------------------------------------
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