Last Call Review of draft-ietf-bier-mpls-encapsulation-10
review-ietf-bier-mpls-encapsulation-10-opsdir-lc-morton-2017-10-24-00

Authors and OPS-DIR,

I have reviewed the LC version of the draft above,
describing the BIER encapsulation of MPLS and non-MPLS
packets, within the limits of BIER domains and sub-domains.

I noted that BIER routers are expected to decrement TTL,
but if the TTL=1, the packet MUST not be forwarded.
But then, there is no requirement for further action
or notification.

A requirement to pass the expired packet elsewhere seems 
to be necessary to generate a notification of TTL expiry,
but any action beyond discard is worded as optional 
(MAY be passed to other layers for processing).
To me, this seems incomplete from a network operation 
perspective.

If this topic has been discussed at some length, please
let us know how this concern about operations was addressed, or
suggest edits/clarifications to the current text.

thanks and regards,
Al