On Wed, Jan 05, 2000 at 06:39:45PM -0500, Bruce R. Babcock said:
> Ed,
>
> http://www.cisco.com/public/cons/isp/documents/IOSEssentialsPDF.zip has quite a bit more info on this an other very useful features.
Great. I have 2.6.9, that's 2.7.2, time for me to update :)
> Unicast RPF drops are counted today by the router under 'sho ip traffic'. Per interface counters are coming RSN, CSCdk70183. Probably 12.0(9)S/T
Great.
router#show ip traffic
IP statistics:
[...]
Drop: 1299111 encapsulation failed, 6264 unresolved, 0 no adjacency
213983 no route, 37278 unicast RPF, 0 forced drop
Yeah, the next thing that I'd like to see would be the
capability to log interface & source addr for the dropped packet.
I guess that's not so important when you have the caveat stated
below: "Do not use this command where asymmetric routing can
occur."
I think I remember discussion about RPF on Nanog like years
ago. I remember the consideration "if there is *a* path back out
the interface, not necessarily the *best* path" would make this
feature more useful. I'm guessing this is difficult (correct me
if I'm wrong) because I'd wager the FIB only stores the best path,
not all paths.
Seems like this feature is most useful on access routers
only, or backbone router interfaces going to stub networks. We
have no stub networks (all POPs are multi-homed internally) and we
are only slowly migrating NAS equipment to Ciscos. This *would*
be nice on the 6400 platform. I haven't upgraded any of my 6400's
to 12.0 yet, but I will be. Is CEF supported on the 6400, do you
know?
> BTW, CSCdk65684 was opened to get the documentation added.
Thanks, Bruce.
Ed
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