01-04-2004 07:34 AM
ge-wan ge-wan ge-wan
P1(OSR)-----P2(OSR)-----P3(OSR)-----P4(OSR)
|FE |FE | FE | FE
PE(36) PE PE PE
As the above figure,I have four OSR connected using
OSM-4GE-WAN's ge-wan interface,at each OSR I use one
L2 GE port connected two one of the 4 GE-WAN interface,
the L2 GE port use 802.1q trunk.
Each OSR use a FE link to connect PE router, the FE links
are access link of a vlan which was trunked by the L2 GE port
to the LE GE-WAN interface.
The GE-WAN subinterface and the L2 GE/FE interface are
all configured to pass jumbo frames.
Everything seems ok and after the VPN and all network run
normally for almost a month,packets bigger than 1500 bytes
can't pass through P1 or P2, and no events logged .
The case never happened to P3 and P4 .
The hardware and IOS version and mpls vpn configuration
are the same at the four OSR.
Who can give me some help or advice about that?
THANKS
mail:td.wu@163.com
01-06-2004 06:07 AM
Would you please clarify what the MTU problem is that you have? It it IP MTU? Are there any firewalls that could be blocking dynamic MTU discovery?
01-08-2004 08:31 PM
There is no firewall.The IP mtu is 1526 and the layer2 fastethernet mtu is 9216.Everything is ok for the mpls ,but after running for almost a month,there is a OSR can't allow the big packet pass through.
01-08-2004 04:58 AM
Away from your issue here you have one which is even worse. P switching and MPLS on the OSM-GIG-WAN modules is not supported. You require the osm+ cards along with the sup720+ module. If you dont have this then you will run into endless problems with blackholing etc etc. I found this out the hard way also so you are not alone.
01-08-2004 08:26 PM
But I do use the OSM-GIG-WAN as the P router,the cisco document hasn't said that OSM can't running as P in mpls vpn.If it's true as you said,I'll come into a nightmare.
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