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A Testbed for Wireless Ad hoc Networks. Telecommunications Research Lab Queen’s University. Wireless Ad Hoc Testbed (objectives). Facilitate the implementation of applications for multi-hop ad hoc networks.
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A Testbed for Wireless Ad hoc Networks Telecommunications Research Lab Queen’s University October 24, 2002
Wireless Ad Hoc Testbed (objectives) • Facilitate the implementation of applications for multi-hop ad hoc networks. • Develop protocols for multi-hop ad hoc networks equipped with IEEE 802.11 (wireless LAN) interfaces. • Develop and evaluate alternate techniques for interworking wireless LANs and ad hoc networks. • Evaluate the performance of TCP/IP over ad hoc networks. October 24, 2002
Wireless Ad Hoc Testbed (Devices) • Dell Notebooks • Sony Vaio Notebooks • Compaq iPAQ handheld PC’s • Intel Pro Wireless LAN Cards • Intel Pro Wireless Access Points October 24, 2002
Wireless LANs (default) • Support for • BSS and ESS. • Single-hop • communication • with AP. Network Backbone October 24, 2002
Ad hoc mode (peer-to-peer) • Independent Basic Service Set (IBSS). • No support for multi-hop connectivity. • Single Code Division Multiple Access (CDMA). October 24, 2002
Multi hop Ad hoc mode Packet Source Packet Recipient • Wireless range is no longer a limitation. • Destination must be part of at least one connected • graph consisting of source. October 24, 2002
Multi-hop Forwarding Architecture • Well-defined SAPs for • use by applications. • Packet processor is the • multi-hop enabler. • Works with existing • TCP/IP suites. • Compatible with all MAC • schemes (past – 802.3, • present – 802.11, future) Application Layer Thin Layer Packet Processor TCP/IP or UDP/IP Medium Access Control October 24, 2002
Packet Processor Message, Destination Incoming RREQs Message Forwarding Dispatcher Sender Or Transmitter RREQ Generator Listener Or Receiver Open Multi-thread sockets Broadcast Incoming messages or RREPs October 24, 2002
Block Diagram Description • Message Forwarding : • Passes the user input to the packet processor. • Dispatcher: • Processes incoming RREQs, RREPs, and data. • Passes incoming messages destined to this specific station. • Decides if a RREQ, a RREP, or a message, needs to be forwarded or not. • Transmitter: • Sends RREP and data messages to the next MT in the route record. October 24, 2002
Block Diagram: The Details • RREQ Generator: • Generates RREQ packets and forwards them to the broadcast entity. • Broadcast: • Broadcasts the generated RREQ packets to neighbors. • Listener or Receiver: • Opens a multi-thread socket and listens for incoming RREPs and messages. • Passes incoming messages and RREPs to the packet processor. • Simultaneous update of routing table entries enhances receipt efficiency. October 24, 2002
Interworking • Allows interconnection between wireless ad hoc networks and infrastructure-based wired and wireless. • Some MTs may be equipped with multiple interfaces one of which connects it to a Distribution System (DS). • 802.3 / ESS / 2.5G / 3G interface. • Software radios. October 24, 2002
Interworking Illustration October 24, 2002
Interworking Paradigms • Interworking is strictly dependent upon the routing protocol, but service discovery is required. • Two types of service discovery: • Proactive service discovery • Reactive service discovery • Choice of service provided may be: • Network-based • Service-based • Energy-based • Etc. October 24, 2002
Multi-hop Applications • We have successfully developed and implemented a multi-player chatting software over a multi-hop ad hoc network architecture. The software uses the packet processor layer to route data packets across the network. • We have successfully developed a multi-player distributed gaming software over multi-hop wireless ad hoc networks. October 24, 2002