Connecting OSPF MANET to Larger Networks

The Open Shortest Path First (OSPF) routing protocol for IP networks performs inefficiently when operated over multihop, broadcast-based radio channels such as IEEE 802.11 in IBSS mode. These types of networks are known more generally as mobile ad-hoc networks (MANET). The Internet Engineering Task Force (IETF) OSPF working group has been considering extensions to OSPF to enhance performance over such channels, and multiple OSPF MANET proposed extensions are advancing to experimental status. Although OSPF MANET performs more efficiently within the MANET itself, it has the side effect of propagating large numbers of routing updates throughout the rest of the OSPF flooding domain. In this paper, we examine OSPF MANET's interaction with attached non-MANET networks, and explore various techniques for reducing the overhead, such as static and dynamic route summarization, route redistribution, cross-layer abstraction techniques, and tunneling approaches between MANET Border Routers (MBR)s. We use a hybrid testbed/emulated network to quantitatively explore the tradeoffs between different approaches.