Gateway discovery and routing in ad hoc networks with NAT-based Internet connectivity

The paper presents gateway discovery and routing schemes for ad hoc networks with NAT-based Internet connectivity. To maintain a reachable gateway set (RGS) and up-to-date routes to gateways, an extended HELLO (e-HELLO) message is used. A mobile node includes its RGS in the e-HELLO message and periodically broadcasts it to neighbors. On receiving the e-HELLO message, a mobile node updates its RGS and routes to gateways. To prevent on-going sessions from being broken, the current default gateway is maintained as long as it is in the RGS and there exists any on-going session. A proxy route reply (p-RREP) message is used to allow a source node to change its default gateway during route discovery. Also, a packet routing scheme for subnet-based ad hoc networks with Internet connectivity is presented. The proposed gateway discovery and routing schemes can efficiently support NAT-based Internet connectivity in ad hoc networks.