[c-nsp] tag-switching on the 6500?

Thu Jan 20 15:12:25 EST 2005

Quite a frightening list you have there.

We're still mid implementation on the Sup720-3bxl related aspects.  MPLS 
so far appears to be stable, however we did run into an issue with a 
"missing" label on an LSR.  We noticed it when we had an IBGP adjacency 
go down.  The /32 of the destination was present in the routing table 
(learned by OSPF), and CEF was populating properly, but the mpls 
forwarding table seemed to have simply lost the appropriate tag entry.  
TAC confirmed the issue, and resetting the LDP session forced the 
rebuild.  To date, it cannot be reproduced.  No ddts has been generated.

We're rolling more into this segment of our network over the next week.  
After we upgrade everything to SXD03, that is. 

Mike Bernico wrote:

>Sure, I'll give you an overview.  Cisco support has been pretty good and
>they are treating all these issues very seriously, but unfortunately we
>are having a few problems.  
>
>We deployed 22 nodes on 12.2.18SXD1 on the advice of Cisco.
>
>We quickly began to experience MLS "freezes" that would cause the data
>plane of the router to stop forwarding some packets correctly, even
>though the control plane advertised the router as a feasible path.
>Those issues are documented in bug CSCef84262 and bug CSCee4986.
>(Pretty much all the bugs I name here are Cisco internal.)
>
>These bugs were resolved in 12.2.18SXD3, however MLS still freezes
>occasionally.  This is because, as far as I can tell, Cisco DEs have not
>implemented a graceful way to recover from an MLS freeze or a mechanism
>to prevent MLS freezes.  So far they have only addressed some of the
>symptoms that cause MLS freezes.   
>
>Currently, on 12.2.18SXD3 we are experiencing the following issues:
>
>1.  Sometimes during normal provisioning activities (VRF changes, adding
>loopbacks, etc.) the router crashes.  This is attributed to CSCsa49900
>and there isn't a fix currently.  We didn't find this bug originally,
>but after experiencing it we've been adding to someone else's P1 case. 
>
>2.  MLS still freezes on occasion but DE does not know why.  We are
>currently running a "development release" of IOS that is designed to
>find the problems.  (rebuild of 12.2.18SXD3 with debug flags on)
>
>3.  We've had at least two occasions since deployment where heat sinks
>have fallen off cards.  In one case the heat sink was loose in the
>chassis when I received it from the factory.  In the other case it came
>loose while in use and caused a short.  
>
>So what issues are you guys having?  Anything I should watch out for?
>
>
>Thanks,
>Mike
>
>
>-----Original Message-----
>From: Greg Schwimer [mailto:gschwimer at godaddy.com] 
>Sent: Thursday, January 20, 2005 11:48 AM
>To: Mike Bernico
>Subject: Re: [c-nsp] tag-switching on the 6500?
>
>We're having our share of issues too.  What are you running into? 
>
>Mike Bernico wrote:
>
>  
>
>>I'm doing LDP on 7600s (same as 6500) with sup720 3BXLs.  While we're
>>having many horrible problems with the 7600, LDP seems to work ok.  
>>
>>I looked up a document that said the sup2/msfc2/pfc2 was ok for EoMPLS,
>>MPLS CoS, and MPLS VPN (not TE) so my guess is that it should work with
>>TDP.  
>>
>>The first thing I'd check is if the packets coming out of the 6500 to
>>the 7500 are getting labeled.  If I had to guess, I'd guess TDP was
>>advertising labels but label imposition isn't happening on your packets
>>because you used card X instead of card Y and card X only labels
>>    
>>
>packets
>  
>
>>on Tuesdays.  (Sorry, I'm bitter)  I'd be especially careful of card
>>support when it comes to L2VPNs.  
>>
>>Good Luck,
>>
>>Mike
>>
>>
>>
>>-----Original Message-----
>>From: Jon Lewis [mailto:jlewis at lewis.org] 
>>Sent: Thursday, January 20, 2005 10:45 AM
>>To: cisco-nsp at puck.nether.net
>>Subject: [c-nsp] tag-switching on the 6500?
>>
>>Is anyone doing tag-switching on 6500s mixed with cisco router
>>    
>>
>platforms
>  
>
>>(7xxx, 36xx)?  While trying to turn up a 6509 (sup2/msfc2/pfc2) running
>>12.2(18)SXD3, I've found that while TDP appears to work, our 7500s fail
>>to
>>switch some packets tagged by the 6509.  I've been afraid to turn on
>>much
>>debugging on live routers passing large amounts of traffic, the above
>>    
>>
>is
>  
>
>>about all the detail I have so far.
>>
>>I'm basically wondering if there's some knob I've not encountered on
>>    
>>
>the
>  
>
>>router platforms that needs to be set on the 6509 in order for
>>tag-switching to work properly, or if it just doesn't entirely work on
>>sup2/msfc2?
>>
>>----------------------------------------------------------------------
>>Jon Lewis                   |  I route
>>Senior Network Engineer     |  therefore you are
>>Atlantic Net                |
>>_________ http://www.lewis.org/~jlewis/pgp for PGP public key_________
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>>
>>    
>>
>
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