[c-nsp] CEF fun in SXF

[Phil Rosenthal]

Bringing this back up from the dead, but we ran into this today on a  
SXF4 box with 6748-dfc3bxl and 6704-dfc3bxl.  Anyone know if this  
will be fixed ever?

TAC seemed to be clueless about this issue.

--Phil
On Dec 8, 2005, at 4:24 PM, Gert Doering wrote:

> Hello colleagues,
>
> we've just had lots of fun with one of our Sup720/12.2(18)SXF  
> boxes, and
> I'm curious whether one of you has been hit by it before, and maybe
> even has a bug ID (which would save me some time with first-level TAC)
> or case number that I could link to...
>
> The box is running perfectly well since 6 weeks, and has seen quite  
> some
> amount of (VLAN-)interface configuration/deconfiguration churn  
> since then
> - new customers are connected, customers move to other VLAN numbers  
> (don't
> ask), interfaces are deconfigured.
>
> Today, I did a pretty standard interface deconfiguration ("no int  
> vlan3305"),
> and all of a sudden, hell broke loose:
>
> *All* directly connected (!) customers had massive packet loss - about
> 50-80% - while packets to non-"connected" targets had no problems  
> at all.
>
> Took me a while to figure out what the problem is (I was looking for
> overload, customer worm infections, out-of-memory hickups, etc.) and
> then I decided to reconfigure the interface, as it was before -  
> very basic
> configuration: interface, IP address, description, uRPF.  Voila,  
> everything
> normal.
>
> Set interface to "shutdown".  Boom, packet loss.
>
> Set interface to "no shutdown".  Everything normal.
>
> It gets more weird.
>
> Removed IP configuration from vlan3305 - so all that's left is
> "int vlan 3305 / no shutdown".  Everything stays normal.  (There is no
> connected route for that interface anymore!!!  How can it affect CEF?)
>
> Remove vlan 3305 from last trunk port -> msfcautostate -> interface  
> goes
> to "down" -> packet loss.  Re-add vlan 3305 -> interface up ->  
> everything
> fine.
>
>
> Next thing I tried was "clear ip route *", then setting the  
> interface to
> "shutdown", and doing "clear ip route *" again.  Aha!  No more  
> packet loss.
>
> A few seconds later, the box told me:
>
> Dec  8 21:53:32: %FIB-4-AUTOREPAIR: CEF database auto-repair executed
>
> ... which seems to confirm my suspicion: somehow the removal of an
> interface messed up CEF for lots/all other directly connected  
> networks.
>
> Huh???
>
>
> Does this sound familiar to anyone?
>
> gert
>
> -- 
> USENET is *not* the non-clickable part of WWW!
>                                                            // 
> www.muc.de/~gert/
> Gert Doering - Munich, Germany                              
> gert at greenie.muc.de
> fax: +49-89-35655025                        gert at net.informatik.tu- 
> muenchen.de
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