Ad hoc On-Demand Distance Vector (AODV) Routing is a
routing protocol
A routing protocol specifies how routers communicate with each other to distribute information that enables them to select paths between nodes on a computer network. Routers perform the traffic directing functions on the Internet; data packet ...
for
mobile ad hoc network
A wireless ad hoc network (WANET) or mobile ad hoc network (MANET) is a decentralized type of wireless network. The network is ad hoc because it does not rely on a pre-existing infrastructure, such as router (computing), routers or wireless acces ...
s (MANETs) and other
wireless ad hoc network
A wireless ad hoc network (WANET) or mobile ad hoc network (MANET) is a decentralized type of wireless network. The network is ad hoc because it does not rely on a pre-existing infrastructure, such as routers or wireless access points. Instead, ...
s. It was jointly developed by Charles Perkins (Sun Microsystems) an
Elizabeth Royer (now Elizabeth Belding)(University of California, Santa Barbara) and was first published in the ACM 2nd IEEE Workshop on Mobile Computing Systems and Applications in February 1999.
AODV is the routing protocol used in
Zigbee
Zigbee is an IEEE 802.15.4-based specification for a suite of high-level communication protocols used to create personal area networks with small, low-power digital radios, such as for home automation, medical device data collection, and oth ...
– a low power, low data rate
wireless ad hoc network
A wireless ad hoc network (WANET) or mobile ad hoc network (MANET) is a decentralized type of wireless network. The network is ad hoc because it does not rely on a pre-existing infrastructure, such as routers or wireless access points. Instead, ...
. There are various implementations of AODV such as MAD-HOC, Kernel-AODV, AODV-UU, AODV-UCSB and AODV-UIUC.
The original publication of AODV won the
SIGMOBILE Test of Time Award in 2018. According to Google Scholar, this publication reached 30,000 citations at the end of 2022. AODV was published in the Internet Engineering Task Force (IETF) as Experimental RFC 3561
in 2003.
How it works
Each node has its own sequence number that grows monotonically over time and ensures that there are no loops in the paths used. In addition, each network component assigned to routing functionality stores its own path index, which contains the address of the next node in the direction of the destination (next hop), its sequence number, and the total distance given in hops, or possibly other metrics designed to measure link quality.
In AODV, the network remains completely silent until a connection is required to forward a data packet. When routes need to be searched on the network, AODV resorts to the following packets defined by its protocol:
* Route request (RREQ)
* Route reply (RREP)
* Route error (RERR)
These messages can be implemented as simple
UDP packets, so routing is still based on the
Internet Protocol
The Internet Protocol (IP) is the network layer communications protocol in the Internet protocol suite for relaying datagrams across network boundaries. Its routing function enables internetworking, and essentially establishes the Internet.
IP ...
(IP).
RREQ packets are broadcast from the source node, so a burst of messages is generated and forwarded through the entire network. When a node in the network receives a request packet, it can send an RREP packet through a temporary path to the requesting node, which can then exploit the newly received information. Generally, each node compares different paths based on their length and chooses the most convenient one. If a node is no longer reachable, a RERR message is generated to alert the rest of the network.
Each RREQ has a "time to live" that limits the times it can be retransmitted. In addition, AODV implements a binary backoff mechanism in case the node does not receive a response to its RREQ, whereby requests are repeated at linearly increasing time intervals up to a maximum set by the implementation.
Evaluation
The main advantage of AODV is that it does not generate traffic in the case of already established and working routes. In fact, the algorithm itself is completely irrelevant as long as it does not turn out to be necessary to send a packet to a node whose route is unknown. Beyond that, distance vector-based routing is computationally simple and does not require large amounts of memory.
However, the protocol takes longer than other protocols to establish a connection between two nodes in a network.
See also
*
Wireless ad hoc networks
A wireless ad hoc network (WANET) or mobile ad hoc network (MANET) is a decentralized type of wireless network. The network is ad hoc because it does not rely on a pre-existing infrastructure, such as router (computing), routers or wireless acces ...
*
Backpressure routing
*
Mesh networking
A mesh network is a local area network network topology, topology in which the infrastructure Node (networking), nodes (i.e. bridges, switches, and other infrastructure devices) connect directly, dynamically and non-hierarchically to as many othe ...
*
Wireless mesh network § Routing protocols
**
List of ad hoc routing protocols
An ad hoc routing protocol is a convention, or standard, that controls how nodes decide which way to route packets between computing devices in a mobile ad hoc network.
In ad hoc networks, nodes are not familiar with the topology of their netwo ...
References
{{DEFAULTSORT:Ad Hoc On-Demand Distance Vector Routing
Ad hoc routing protocols
Computer network technology