Providing Unsignaled Critical Services for a Future Satellite Packet Network

A Future Satellite-Based Packet Network (FSPN) includes highly mobile users operating in demanding environments. Packet-switched traffic encompasses applications that are robust in the face of these challenges but also includes applications whose operational utility requires a relatively low delay, jitter, and loss performance. On-path, in-band signaling protocols are inappropriate for many terminals. For these, minimum delay, low loss transfer characteristics are provided by Unsignaled Critical Services (UCS) for which aggregate usage levels are communicated out-of-band. UCS need not be strictly static; time-of-day constraints are available, allocations can be invoked through network management interfaces, or short-term network managment interaction can change allocations. UCS are implemented through the use of IP Differentiated Services, specifically the Virtual Wire Per-Domain Behavior, but includes resource allocation interactions between the IP network layer and the Per-hop Behavior provided by the link layer in a manner unique to satellite systems. The network is further constrained by the use of encyrption which limits packet inspection techniques to the in-the-clear packet header fields only. The architecture of UCS is described, issues for users and providers of UCS are explored, and issues in the network-link layer interactions are examined. Current work on UCS is focused on these issues.