This bit mask indicates optional session values for this tunnel. The following describes these bit fields: fastRerouteThis flag indicates that the any tunnel hop may choose to reroute this tunnel without tearing it down. This flag permits transit routers to use a local repair mechanism which may result in violation of the explicit routing of this tunnel. When a fault is detected on an adjacent downstream link or node, a transit router can re-route traffic for fast service restoration. mergingPermitted This flag permits transit routers to merge this session with other RSVP sessions for the purpose of reducing resource overhead on downstream transit routers, thereby providing better network scaling. isPersistent Indicates whether this tunnel should be restored automatically after a failure occurs. isPinned This flag indicates whether the loose- routed hops of this tunnel are to be pinned. recordRouteThis flag indicates whether or not the signalling protocol should remember the tunnel path after it has been signaled.