MPLS on FE between 7600 and 7500

Unanswered Question
Oct 1st, 2007

I have a 7500 that connects to a 7600 using a PA-FE-TX interface and I'm using MPLS. When I set the MPLS mtu on the 7600 it requires me to adjust the interface MTU (6700 series switch card) as well (from 1500 to 1524). The 7500 will allow me to send the MPLS MTU to 1524, but it says that I can't adjust the interface MTU. Is there a way around this? I've searched the forum and didn't find a definitive answer. I'd like to adjust the 7500 if possible, but if not, then I could do the 7600.

Any help or guidance is appreciated.


I have this problem too.
0 votes
  • 1
  • 2
  • 3
  • 4
  • 5
Overall Rating: 0 (0 ratings)
lamarhinson Mon, 10/01/2007 - 16:57

Could you provide more background. You might want to just stick with the 6700 verses the 7500. Meaning that the problem is with the older hardware.

8wsmith Tue, 10/02/2007 - 07:20

i'm not in a position to remove the 7500 - it's a PE device and the 7600 is the P router. Is this the information you were looking for?

mlund Wed, 10/03/2007 - 00:27


You can probably solve this by configure "mtu 1524" and ip "ip mtu 1500" on 7600, and on 7500 "mpls mtu 1524"

This is what I did under a migration from 7200/7500 to 7600


8wsmith Wed, 10/03/2007 - 06:19


thanks for the tip! - we are trying it now in our lab.


8wsmith Wed, 10/24/2007 - 13:10

Thanks again for the tip - it worked great and we are now running in production.


This Discussion