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

[Mike Bernico]

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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