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Can't enable MPLS on 6509-E

Unanswered Question
Apr 18th, 2012
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I've got a 6509-E in the lab at the moment for some pre-deployment testing, however I don't seem to be able to enable MPLS on a select interface.

router#conf t

router(config)# interface gi1/48

router(config-if)#mpls ip


As you can see after I enter the "MPLS IP" command it simply backs out of interface level configuration back to global exec, and naturally the MPLS command doesn't show in configuration for that interface.

Am I missing something obvious or do I have a genuine issue?

I'm running a SUP720-3BXL with WS-X6748-GE-TX line cards with the DFC upgrade (WS-F6700-3BXL).

The IOS is: s72033-adventerprisek9_wan-mz.122-33.SXI2a.bin

Any thoughts?


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Overall Rating: 5 (1 ratings)
Peter Paluch Wed, 04/18/2012 - 08:39
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Is the port pre-configured with no switchport and assigned an IP address?

It may be possible that the MPLS is only supported on selected line cards but I have no personal experience with 6500 boxes so this has to be taken with a grain of salt. Hopefully someone with bigger experiences joins this thread!

Best regards,


Leo Laohoo Wed, 04/18/2012 - 15:59
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Multiprotocol Label Switching (MPLS)

I've never seen that command before.  Try the link above.

Peter Paluch Thu, 04/19/2012 - 04:43
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You mean using the tag-switching ip ? Right, that was the original command to activate MPLS and its predecessor, Tag Switching... yeah, I remember seeing that command on earlier IOSes. Most of recent IOSes have reverted to using mpls ip instead of the tag-switching ip. Thanks for pointing this out, hopefully it solves the mystery here!

Best regards,


DuncanM2008 Thu, 04/19/2012 - 05:20
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Many thanks for your input Peter & Leo, in the end I think this problem boiled down to a supervisor issue of some sort.

Previously when I treid to enable the command it was after I'd done some NSF/SSO testing by rebooting a supervisor, and was running from the new Active SUP (was previously standby). So possibly a dCEF sync issue of some sort, based on the fact MPLS requries an operational FIB table from CEF.

Once I cold-powered the chassis again and let everything start fresh I was able to enter the command succesfully, might be worth noting with 12.2SXI I also had to enable:

"mpls label-protocol ldp"

Seems because 12.2SXI has support of both TDP & LDP that LDP isn't default.

Once I did that the LDP session came up with the 7204 VXR running IOS 15.

Also "tag-switching ip" isn't supported on 12.2SXI, I checked this first to see if needed to run the original incarnation of MPLS / Tag Switching.

Many Thanks!


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