[c-nsp] MTU Issue on QinQ Eth link with MPLS

[Masood Ahmad Shah]

Well, interesting.. sometimes Cisco guys forget to import some cool
features; I don't know why but it has been seen on some occasion. Better you
down grade to the release which support baby giants....

For those switches that support up to 1530 bytes, the default MTU value is
1500. If you want to change this, use the global configuration command that
is available for versions of software above 12.1(6)EA2. Here is sample
configuration and verification:


This URL might help...

http://www.cisco.com/en/US/products/hw/switches/ps700/products_configuration
_example09186a008010edab.shtml


Regards,
Masood Ahmad Shah



-----Original Message-----
From: mb2 at os.datafx.com.au [mailto:mb2 at os.datafx.com.au] 
Sent: Friday, January 04, 2008 3:06 AM
To: Masood Ahmad Shah
Cc: cisco-nsp at puck.nether.net
Subject: RE: [c-nsp] MTU Issue on QinQ Eth link with MPLS

Quoting Masood Ahmad Shah <masood at nexlinx.net.pk>:

> Well, better you check current MTU settings using command
>
> # sh interfaces | inc MTU
>
> And cheers :)
>
> Yes of course you need to adjust routers MTU as well; if you are running
> with MPLS or gre
>

Thanks Masood.

I've run into a strange problem on the 2950's - Both devices are 
C2950G-24-EI (Which support baby giants), but the one with the more 
recent IOS is only reporting that it supports 1500 byte mtu?:

Model number: WS-C2950G-24-EI System serial number: FOC0833X3M8

System image file is "flash:c2950-i6q4l2-mz.121-22.EA7.bin"

No baby giant support:

gc-sw-08(config)#system mtu ? <1500-1500> MTU size in bytes



Whereas:

Model number: WS-C2950G-24-EI System serial number: FOC1012Z5BJ

System image file is "flash:/c2950-i6q4l2-mz.121-22.EA6.bin"

Baby giant support:

ESW01-BNE(config)#system mtu ? <1500-1530> MTU size in bytes


I compared both images on the Feature Navigator, and there is no 
mention of any Features unique to the images other than "IEEE 802.1x - 
Auth Fail VLAN" on the EA7 vers.?



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