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DSR Status Update
David B. Johnson
Rice University
Department of Computer Science
http://www.monarch.cs.rice.edu/
dbj@cs.rice.edu
55th IETF
Monarch Project
DSR: Dynamic Source Routing Protocol
Divides routing problem into two parts:
• Route Discovery: only try to find a route to some destination
when 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:
– Use of multiple network interfaces
– Implicit source routing
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
• 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.
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