Range Extension via an Internet Protocol (IP) - Based Satellite Network

Range extension, originally a radio communications term, refers to use of intermediate nodes or special communication techniques to provide connectivity between two nodes that otherwise cannot communicate. In this paper, we describe network architectures for providing range extension service through an IP-based satellite network such as the transformation communications satellite (TSAT). In the most general case, IP-based range extension covers intra as well as inter domain connectivity. In addition to using TSAT when it is the only means for providing connectivity, the scenario where a user network has complete intra-domain reachability yet may choose to use a route provided by an external network is also considered. The former application may arise when a user network consists of geographically disparate sites or when a user network that is initially connected may become disconnected due to mobility. The latter can arise for load sharing across internal and external routes to better utilize bandwidth or when the external route has better quality of service (QoS) characteristics. A wide range of solutions developed by the Internet Engineering Task Force (IETF) can be adopted for IP-based range extension. Potential solutions include Layer 3 and Layer 2 virtual private networks (VPNs), extending user network interior gateway protocol (IGP) to the external network, use of IP tunnels, and modifications to the way that routes are redistributed between IGPs and exterior gateway protocols (EGPs). This paper provides an overview of these solutions and describes how they can be used for TSAT range extension service