Ad hoc On-Demand Distance Vector

Ad hoc On-Demand Distance Vector
Name	Ad hoc On-Demand Distance Vector
Abbreviation	AODV
Category	Routing protocol
Introduced	1999
Designer	Charles Perkins, Elizabeth Royer
Used for	Mobile ad hoc networks

Ad hoc On-Demand Distance Vector. AODV is a reactive routing protocol designed for dynamic wireless networks where mobile nodes move unpredictably, developed in the late 1990s by researchers associated with institutions such as University of California, Santa Barbara, Sun Microsystems, and influenced by projects at DARPA and standards work at the Internet Engineering Task Force. It emphasizes on-demand route discovery and loop-free unicast routing for environments typified by research initiatives like MANET and deployments linked to IEEE 802.11 and 4G LTE testbeds. The protocol's original specification was presented in academic venues alongside protocols such as DSDV and DSR and has been implemented in operating systems like Linux and simulators including ns-2 and ns-3.

Overview

AODV operates without centralized control, targeting topologies similar to those in projects at MIT and field experiments by US Army Research Laboratory, using mechanisms comparable to contemporaneous work at Bell Labs and discussions at ACM SIGCOMM. The design balances concerns articulated in workshops at IEEE INFOCOM and reports from IETF MANET Working Group, while its applicability spans trials by institutions like Carnegie Mellon University and deployments associated with Cisco Systems research labs.

Protocol Operation

Route discovery in AODV uses broadcasting techniques reminiscent of methods studied at Stanford University and adopted in protocols evaluated at Georgia Tech and University of Illinois at Urbana-Champaign, employing sequence numbers to guarantee freshness similar to timestamping strategies discussed in ACM MobiCom. Nodes exchange Route Request and Route Reply messages in patterns analogous to signaling used in IS-IS and OSPF research, and maintain routing tables in a manner implemented in network stacks by teams at Red Hat and Apple Inc. for experimental platforms.

Routing Metrics and Route Discovery

AODV uses hop counts and sequence numbers as primary metrics, a choice debated in comparisons with metrics used in studies by Northeastern University and standards comparisons at ITU-T; alternative metrics such as link quality and bandwidth were proposed in follow-up work at University of California, Berkeley and evaluated in simulations by Tsinghua University and University of Cambridge. Route discovery relies on controlled flooding, optimizations inspired by algorithms from Bellman–Ford research and multicast work at IETF IDMR, and enhancements proposed in papers from University of Waterloo and ETH Zurich that adapt metrics for quality-of-service scenarios examined in 3GPP workshops.

Performance and Scalability

Performance analyses of AODV appear in comparative studies alongside OLSR and ZRP from research groups at Kings College London and University of Texas at Austin, showing trade-offs in latency, throughput, and control overhead under mobility models used by NSF-funded projects and experimental campaigns by European Commission initiatives. Scalability challenges raised in evaluations by University of British Columbia and KTH Royal Institute of Technology motivated hierarchical and hybrid extensions, and real-world tests in city-scale trials coordinated by MIT Senseable City Lab and municipal trials in Singapore assessed limitations under dense node populations.

Security Issues and Enhancements

The protocol's reactive nature exposes it to threats studied in security research from Carnegie Mellon University's CERT centers and adversary models evolved in papers from Harvard University and SRI International; known attacks include route spoofing and blackhole behaviors analyzed in studies at Oxford University and mitigations drawn from cryptographic work at RSA Laboratories and public-key schemes tested at NIST. Enhancements such as secure sequence number handling, cryptographic signatures, and trust frameworks were proposed in collaborations involving Johns Hopkins University and evaluated in consortia including ENISA and academia-industry partnerships with Microsoft Research.

Implementations and Variants

Implementations of AODV exist in network simulators like ns-2 and ns-3, operating system kernels such as Linux networking modules, and embedded platforms supported by vendors like Qualcomm and Texas Instruments; variants including AODVv2 (DYMO) and extensions from research teams at University of California, Los Angeles and Tsinghua University introduced modifications for multicast, quality-of-service, and energy efficiency studied by groups at Imperial College London and Delft University of Technology. Experimental integrations with protocol suites developed at IETF and testbeds managed by GENI and PlanetLab have facilitated broader evaluation and informed ongoing standardization discussions.

Category:Routing protocols