Analysis of PCE operation for reroute

A first analysis of PCE operation, shall provide potential tracks to follow, to allow path computation when a path computation is triggered (whatever is the request : service-create/reroute/feasibility -check ....) for an existing service that may be affected by a failure. Indeed, in this case, the PCE shall be allowed to use resources that are already in use by the current service.
Acceptance criteria : one or several approach are proposed for PCE adaptation to cope with path calculation accross resources used by the service to reprovision.