David B. Johnson

Rice UniversityDepartment of Computer Science

http://www.monarch.cs.rice.edu/

dbj@cs.rice.edu

DSR Status Update

Monarch Project

55th IETF

DSR: Dynamic Source Routing Protocol

Divides routing problem into two parts:

• Route Discovery: only try to find a route to some destinationwhen you don’t have one and need one

• Route Maintenance: only while you’re actually using a route,try to keep it working or fix it in spite of changes

Important properties of DSR:

• All aspects of protocol operation are entirely on-demand

• Nodes ignore all topology changes not affecting them

• Overhead scales automatically as movement increases

• Zero overhead when stationary and found routes already

• Also can support unidirectional links and asymmetric routes

• Extensive implementation and demonstration with real workloads

New DSR Implementation Work

Implementation under Windows jointly with Microsoft Research:

• Implemented at the link layer

• Uses the same primitives as DSR:

– Route Discovery

– Route Maintenance (explicit, due to NDIS limitations)

– Source routing

• Packet formats based on those in the DSR Internet-Draft

• Not fully optimized (salvaging, expanding ring)

• We plan (and expect) to be able to release the code

Recent Papers (Security)

• Yih-Chun Hu, David B. Johnson, and Adrian Perrig. SEAD: Secure Efficient Distance Vector Routing for Mobile Wireless Ad Hoc Networks. WMCSA 2002, June 2002.

• Yih-Chun Hu, Adrian Perrig, and David B. Johnson. Ariadne: A Secure On-Demand Routing Protocol for Ad Hoc Networks. MobiCom 2002, September 2002.

• Yih-Chun Hu, Adrian Perrig, and David B. Johnson. Efficient Security Mechanisms for Routing Protocols. NDSS 2003, February 2003, to appear.

• Yih-Chun Hu, Adrian Perrig, and David B. Johnson. Packet Leashes: A Defense against Wormhole Attacks in Wireless Ad Hoc Networks. INFOCOM 2003, April 2003, to appear.

Recent Papers (Other)

• Yih-Chun Hu and David B. Johnson. Design and Demonstration of Live Audio and Video over Multihop Wireless Ad Hoc Networks. MILCOM 2002, October 2002.

• Yih-Chun Hu and David B. Johnson. Ensuring Cache Freshness in On-Demand Ad Hoc Network Routing Protocols.POMC 2002, October 2002.

• Santashil PalChaudhuri and David B. Johnson, Power Mode Scheduling for Ad Hoc Networks (Extended Abstract),ICNP 2002, November 2002.

Internet-Draft Status

Adding some things (back) to the draft:

• Have been in previous drafts: draft-ietf-manet-dsr-03.txt, Oct 1999:

And of course, lots of proofreading of the draft

Expect to complete final version of draft by end of December

– Use of multiple network interfaces

– Implicit source routing

Use of Multiple Network Interfaces

• Allows routing between different types of networks

• Example: some nodes have both short-range and long-range radios, but most have only short-range

• Also allows integration with Internet and Mobile IP

• Implemented and demonstrated in DSR testbed, Pittsburgh, December 1998 through March 1999

• Documented in:

– Josh Broch, David A. Maltz, and David B. Johnson. Supporting Hierarchy and Heterogeneous Interfaces in Multi-Hop Wireless Ad Hoc Networks. In Proceedings of the Workshop on Mobile Computing, ISPAN’99, June 1999

– David A. Maltz, Josh Broch, and David B. Johnson. Lessons From a Full-Scale Multi-Hop Wireless Ad Hoc Network Testbed. IEEE Personal Communications, February 2001

Implicit Source Routing

• Establishes hop-by-hop state based on source route from sender

• Avoids carrying source route in most packets

• All state is soft state – no correctness problems if it is lost

• Implemented and demonstrated in DSR QoS demo, DARPA GloMo PI meeting, Eatontown, NJ, July 2000

• Documented in:

– Yih-Chun Hu and David B. Johnson. Implicit Source Routes for On-Demand Ad Hoc Network Routing. In Proceedings MobiHoc 2001, October, 2001.

– Yih-Chun Hu and David B. Johnson. Design and Demonstration of Live Audio and Video over Multihop Wireless Ad Hoc Networks. In Proceedings of MILCOM 2002, October 2002.