[c-nsp] MTU - PPPOE

[Paul Stewart]

Here's an age old topic but with a twist....
 
We provide DSL services to a number of customers (as a telco) and their MTU
must be 1492 in order for it to work properly.  This however is not true
when we wholesale DSL from another telco (Bell Canada) which serves are
largest DSL area.
 
They (Bell) send us l2tp tunnels from their Juniper gear via a series of
dot1q vlans which terminate on some Redback units (currently - but moving to
7206VXR shortly).  With this arrangement we must use an MTU of 1452 at
customer sites.
 
My question is hopefully simple.. is there a way to provide service to these
customers with an MTU of 1492?  Seems like a simple question but I have a
feeling it's complicated to resolve....
 
Basically the layout is:
 
Bell Demarc --> Cisco 2924 --> OC-12 transport --> Cisco 6509 --> Redbacks
 
MTU is 1500 along the entire route....
 
Thanks,
 
Paul