3. VANET is a new kind of Ad hoc network .
VANET is an assortment of vehicular nodes that act as
mobile hosts establish a transient network without the
assistance of any centralized administration or any
established infrastructure.
VANET is called autonomous & self configured network.
Two kinds of communication can be done.
Vehicle to vehicle.
Vehicles to roadside units.
3
Introduction
4. 4
Introduction
Performance of such kind of communication between
vehicles depends on various routing protocols.
MANET ( Mobile Ad-hoc Network )
Manet Properties : dynamic topologies, limited bandwidth,
limited energy and many more.
Vehicular ad hoc network (VANET) is a sub class of MANET
with some unique properties.
Vehicle-to-Vehicle (V2V) and Vehicles-to-Roadside (VRC) or
Vehicle-to-Infrastructure (V2I) Communications.
7. 7
Routing in VANET
The main difference between MANETs and VANETs is the mobility
pattern and suddenly changing topologies.
VANET Problem : configuration, number of vehicles at varied times
of the day, demographics, mobility patterns, random change in
vehicles incoming and outgoing the network.
Typical adhoc routing protocols inappropriate for VANET.
VANET Routing Protocols:
Position Based Routing Protocol
Topology Based Routing Protocol
Broadcast Based Routing Protocol
Cluster Based Routing Protocol
Geo Cast Based Routing Protocol
9. 9
Routing in VANET
Position based routing protocol
A source node communicate with the destination node using their
geographical position besides of its network address.
This protocol required the global positioning system (GPS).
Examples of this routing protocol are Distance routing effect
algorithm for mobility (DREAM) and greedy perimeter stateless
routing (GPSR).
good performance in highway
environment
Need of global route not required.
With high mobility in environment
stability increases.
More suitable for network distributed
nodes.
Lowest processing overhead.
It needs global positioning system
position (GPS).
GPS device stop working in tunnel .
Location server sometime goes
into deadlock state.
10. 10
Routing in VANET
Topology based routing protocol
It uses the available information about the link that resides in the
network to forward the packet from source node to the destination
node.
These can be classified into three main categories:
Proactive Routing * Reactive Routing * Hybrid Routing
Surely provide a route from source hop
to destination hop.
Can send unicast, multicast &
broadcast type of messages.
Consumption of lesser resources.
Few bandwidth consumption
Beaconless
More overhead because it needs
routes discover mechanisms and
maintaining delays.
Sometimes it fails to discover a
complete path because of
frequently moving vehicles.
Unnecessary flooding.
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Routing in VANET
Proactive routing protocol
Protocol chooses the route path which usually depends on shortest
path algorithms.
They keep information of all connected nodes in form of tables
because these protocols are table based. Furthermore, these tables
are also shared with their neighbors.
Route discovery is not required.
Exchange partial routing update
information with neighbors only, so
consume lesser bandwidth.
For real time applications it has very
low latency.
Maintenance of unused routing paths
occupies a large content of the
accessible bandwidth.
The overhead of processing the
routing table and storage complexity
increases with the increase in network
size.
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Routing in VANET
Reactive routing protocol
Reactive routing protocol is called on demand routing because it
starts route discovery when a node needs to communicate with
another node thus it reduces network traffic
Periodic flooding is not required. It
is only done when demanded.
It saves the bandwidth because it
is beaconless.
Memory requirement is less.
It responses at the time of link
failure.
High latency for route finding.
Disruption of nodes
communication because of
excessive flooding among the
vehicles.
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Routing in VANET
Hybrid Ad Hoc routing protocol
This protocol divides the network into two regions: local and global.
This protocol combining local proactive routing protocols and global
reactive routing protocols together to minimize routing overhead and
delay due to route discovery process.
Higher efficiency & scalability. High latency for finding new
routes
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Routing in VANET
Broadcast based routing protocol
Broadcasting routing protocol floods the packet over the entire
vehicular network among all available nodes inside a broadcast
domain.
Since packet is delivered via many
nodes so the packet transmission is
reliable.
Minimize overhead by occurrence
of broadcast storms.
Consume the large amount of
network bandwidth.
Many replicated packets reached
to the node.
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Routing in VANET
Cluster based routing protocol
Various vehicles having similar characteristics like velocity, direction
etc. are grouped together to form a cluster in the network.
To manage the communication among various nodes within cluster or
with other clusters, a cluster head is needed.
If the packet to be sent in the same cluster then it is done by using the
direct path, but when the destination node is outside the cluster then
the cluster head create a virtual network infrastructure which provide
scalability.
It has good scalability of large
networks.
Delays in highly dynamic networks.
Network overhead is increased.
16. 16
Routing in VANET
Geo Cast based routing protocol
It uses mobicast messages to communicate with the vehicles .
Its main factor of consideration is time and the main goal is that the
communication between vehicles within prescribed region at a
particular time which is known as zone of relevance (ZOR).
Whenever the destination node belongs to the other ZORs then
communication is done by using the zone of forwarding (ZOF).
The vehicle comes inside the ZOF has the responsibilities to forward
the data packet to the other ZORs.
Its various examples are like IVG, DG-CASTOR
Reduced network overhead and
congestion.
Reliable packet delivery in highly
dynamic topology
Packet transmission delay due to
network disconnection.
