[nsp] SMDS -> ATM ?

[RH List Account]

Good afternoon list folks,

I'm running into a bit of a brick wall here, and am probably missing
something.

We use an ATM-OC3 to aggregate our clients' frame connections.  Works like a
charm:

interface ATM3/0.23 point-to-point
 description xxx
 bandwidth 256
 ip address xxx
 pvc xx/yy
  oam-pvc manage
 !

Simple. Works.

Now we're trying to move our SMDS circuits onto the same pipe (why not, save
ports and cash!).  

Our telco (BTC) insists they're doing everything the same as normal, and it
should "just work". It doesn't.

So, here's the config...

vc-class atm SMDS
  ubr 10000
  oam-pvc manage
  encapsulation aal5snap   <--  tried with and without
  protocol ip inarp broadcast
!
interface ATM3/0.32 point-to-point
 description SMDS 10Mbps to xxx client
 ip address xxx
 pvc xx/yy
  class-vc SMDS


Any ideas?  I'm at a loss, and the telco is not being helpful.

Thanks in advance

Rob