WATM — New Access Bridge cannot distinguish between different kinds of handoff

In Terminal Initiated Handoff (section 8.3) and Access Recovery
(section 8.4.2) the new Access Bridge needs to invoke different
methods depending on the kind of handoff (step 4 in 8.3.2 and step 5
in 8.4.2.2). However, it is not possible for it to make this
distinction based on the information it has received in previous steps
of the handoff.

Furthermore, in Network Initiated Handoff (section 8.2) the only
distinction for the new Access Bridge is the previous invocation of
transport_address_request. But it is possible that the terminal could
not establish connectivity during the handoff procedure and resorted
to another kind of handoff later. So in this case the new Access
Bridge misidentifies this handoff as network initiated.

The simplest way to correct this seems to be to add an element for
handoff type into RecoveryRequestBody (section 7.2.4). This solution
also looks quite clean.

see above