ABSTRACT
Contents 25.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 612 25.2 A Novel Modular Routing Framework . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 613
25.2.1 Routing Architecture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 613 25.2.2 Marnetd API . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 614
25.2.2.1 Network I/O Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 616 25.2.2.2 Packet Forwarding and Source Routing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 619 25.2.2.3 On-Demand Routing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 621 25.2.2.4 Task Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 622 25.2.2.5 Utility Functions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 623 25.2.2.6 Local Terminal Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 624 25.2.2.7 Additional Supporting Functionality . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 626
25.3 Marnet: Marburg Ad Hoc Network Emulation Testbed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 627 25.3.1 Topology Manager . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 627 25.3.2 Xen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 629 25.3.3 Network Topology. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 630 25.3.4 Discussion. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 630
25.4 Related Work . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 632 25.4.1 Routing APIs and System Services. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 632 25.4.2 Network Simulators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 633
25.5 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 634 25.6 Acknowledgment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 635 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 635
25.1 Introduction Mobile ad hoc networks (MANETs) are spontaneously formed networks of mobile devices utilizing wireless communication technology to interconnect with each other or to other networks. An essential property of such networks is their ability to self-organize in terms of both handling the inference of available communication paths from broadcast or unicast messages and relaying data destined for remote nodes. In other words, a MANET does not rely on any pre-existing infrastructure such as access points or relays, but rather requires the participating nodes to act as routers for other devices in their range, forwarding data as needed. However, finding optimal paths in a distributed fashion is complicated by several factors [15]:
■ Most scenarios allow the participants to move around freely, which may result in significant topology changes even in networks with a relatively low “nomadicity" due to different effective transmission ranges. The latter are the result of heterogenous hardware characteristics such as transmission power levels and antennae features or environmental conditions such as obstructions or interferences.
