3. if a) is selected there is no other choice than an upstream flowspec in the Path msg and a upstream tspec in the Resv message
That *does* raise an interesting question. Namely, does the ingress know the bandwidth to request? If it does then there is no need for a TSpec on the Resv as the reservation has already been made commensurate with the FlowSpec on the Path.
If the ingress does *not* know and needs to see a TSpec from the egress, then we need another Path exchange after the Resv in order to make the actual reservations. In that case it really would be a mess and not worth trying to shoe-horn into a bidirectional LSP format.
A