IP over SONET considered harmful?

Not decrementing the IP TTL at each LSR hop no more breaks the
IP TTL mechanisms than does frame-relay or ATM.

If this is the goal why not have a knob to generate an "appropriate"
ICMP message when IP TTL is exceeded, where appropriate may
mean "not relating to the MPLS infrastructure" or "none at all"?

If people really really want to make sure IP ttl is decremented
only by one no matter how many MPLS hops there have been, then
they are obviously not worried about forwarding loops across
a possibly very long (and consequently probably very expensive)
MPLS cloud, and should not object to my earlier proposal for
the configuration command.

ps. In fact, there may even be some ISP's that would prefer that
their internal L2 infrastructure remain invisible.

These ISPs are wankers.

  Sean. (and that is the politest way I would put it)

Sounds reasonable to me. My point was that decrementing the IP TTL,
whether it be at each LSR or only at egress, should be a decision
that can be made by the provider.

- paul