[rbridge] Hop Count processing

[Dinesh G Dutt]

I'd like to modify the hop count processing in section 3.6 (of draft 12) 
slightly. The advantages of this alignment are:
  - Make it possible to implement something like L2 traceroute
  - Align it with what is done in other protocols such as IP and MPLS 
for development and operational simplicity.
  - Not forward a frame that will be dropped by the next hop.

The existing text at the beginning of 3.6 is:

The Hop Count field is a 6-bit unsigned integer. Each RBridge that is
about to forward a TRILL data or ESADI frame MUST check this field
and discard the frame if this field is zero. If this field is greater
than or equal to 1, it MUST be decremented in the forwarded frame.

The suggested replacement is:

The Hop Count field is a 6-bit unsigned integer. It is decremented by 1 
by each Rbridge that forwards a TRILL encapsulated frame. The frame is 
dropped if either the Hop Count in the received frame is 0 or the Hop 
Count is decremented to 0.

Comments ?

Dinesh

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