VANET ROUTING PROTOCOLS
Now coming to
different routing protocols, VANET routing protocols can be classified into 5
broader categories which also have their subdivisions. The classification is done
on the basis of the route update methods and the positions.
Routing protocol hierarchy 10
BASED ROUTING: The communication between source and destination node uses the
geographical location rather than the network address. The exact position of
the nodes which took part in the communication can be accessed via periodically
transmitted beacons 11. GPS is the necessity of the protocol to determine the
location of different vehicular terminals. They can work easily without
establishing or maintaining routes. They can be further classified into 2
a. GREEDY PARAMETER STATELESS ROUTING (GPSR): GPSR makes use of the geographical location. Each node has the knowledge
of the corresponding neighbour and it chooses the next hop which is nearest to
the respective destination. This procedure is known as greedy forwarding. The
concept of HELLO messages comes into the picture in this procedure, if the
HELLO message is not captured from the corresponding node then it assumes that
the neighbour is out of the respected area 12
b. DISTANCE ROUTING EFFECT ALGORITHM FOR
MOBILITY(DREAM): This Protocol is
basically used in unformed architectures. Each terminal maintains a Position
table which has the location of all the nodes present in the network and thus a
position Packet is updated on a regular time interval. A packet delivery rate
is dependent on the speed of the respective source node 13.
Mobility Scenario 13
Intersection Structure 13
1.Position based routing protocol is suitable in
highway because of high mobility of the vehicles and less obstacles 10
2.There is no
need to maintain the routing table and thus overhead is low.
3. The latency is low in this protocol.
1.Gps is the
necessity of the protocol, if GPS is not working than this protocol might not
2.This protocol is non-responsive in the
case of link failure.
3.As the network size increases, the
complexity of the storage also increases so overhead increases in that case
4.Also bandwidth consumption is high
because of the routing paths which are not used 10.
2. TOPOLOGY BASED ROUTING PROTOCOL: There is
unique address assignment to all the terminals in this protocol. This protocol
can be further classified into three parts:
Topology Based Routing Protocol Classification
a. Proactive Routing Protocol: Also known as Table driven protocol, Shortest path algorithms forms the
basis of these protocols. Whenever, there is change in the network, all the
participating terminals updates their routing tables. DSDV (Destination
Sequenced Distance-Vector) is widely used which is a distance vector routing protocol.
In this protocol, each record in the routing table consists of a sequence
number, the sequence number is even if the links are present otherwise they are
odd if link is inactive 14. The DSDV mechanism is as follows:
UPDATE TECHNIQUE: Each terminal transfers
the updates in regular time instances which consists of their sequences number
and the respective updates of their routing tables. When two consecutive routes
to a final point are received from two corresponding neighbour terminals then
it selects the one which has higher sequence number, however in case if the
sequence numbers are exactly same then the decision is based on the hop count.
Thus, it provides loop free routes 14.
TWO-WAY MECHANISM: In this mechanism
whole dump that is full routing table can be transferred to the neighbor
terminal. It is optimal in case when the network update is more continual and
when there are less distortions in the network. Next hop will be assigned as
the first terminal going forward towards the final position of hops thus the
exact number of the terminals available between the source and the destination
Figure 11: DSDV
b. Reactive Routing Protocol: This is also known as on-demand routing protocol in
which the routing path is selected whenever it is required hence only used
routing paths are taken into the consideration. This type of protocols is best
suited to the dynamic network where there is restricted pattern of the
available routes 10. It can be further classified into 3 categories:
AODV (AD HOC ON-DEMAND DISTANCE VECTOR ROUTING): In AODV the network is constant till the time a proper
association is required. The source terminal transmits a appeal message
whenever it needs a particular path. When the final location collects the
appeal then it retransmit the reply message via a short-term route to the source
terminal. The source terminal then starts the interconnection utilizing the
path which has minimum number of hops, thus the entries which are not used are
deleted after certain interval 14. Every path request has a certain sequence
number assigned which are different from other respective paths. Thus, it helps
in bypassing repeated path requests.
Figure 12: AODV
DSR (DYNAMIC SOURCE
ROUTING): It is also an
on-demand reactive routing protocol in which the source terminal controls the
whole path for every routing procedure 15. This protocol follows a 2-phase
mechanism as follows:
i. Route Discovery Phase: Whenever there is requirement for the route it
transmits the route appeal and the terminals which collects the packets
retransmit them consequently.
ii. Route Maintenance Phase: If there are presence of errors in the transmitted
messages then there will be the deletion of the particular path from the route
cache maintained and thus another route to the destination is used.
With the use of DSR redundancy can be maintained as
whenever the main route crashes, the alternative route comes into the picture
without calling the route delivery procedure 15. For every route request,
there is a route reply and It has a RREQ format which has an initiator id,
initiator sequence, Target ID and Partial route.
Figure 13: RREQ
Figure 14: The
query/reply phase in the route discovery procedure 15
TORA (TEMPORALLY ORDERED ROUTING
ALGORITHM): TORA is another on-demand routing protocol which makes
use of multi-hop routes. This protocol is not based on shortest path algorithm
and therefore, the routing architecture does not constitute distance 15. It
creates a directed acyclic graph(DAG) which contains the various terminals
between the source and the destination and the source node is the main route.
It has a 3-phase mechanism:
i. Route Creation: Formation of DAG
ii. Route Maintenance: It comes into picture in the case of link failure.
iii. Route Erase: To erase the invalid routes.
c. HYBRID ROUTING PROTOCOL: This type of topology based protocol carries
features of both proactive and reactive protocols, thus the main goal is to
reduce the proactive routing protocol overhead and minimize the latency of the
route discovery procedure 16. It divides the network to multiple areas known
as Zones to get the optimal route discovery and maintenance procedures 15. It
is further divided into 2 categories:
ZRP: In this type of protocol, the terminals in the network are further
distributed into special areas known as zones according to many such as power
of broadcasting, moving speed of the nodes and several other factors. ZRP works
as a Proactive protocol for large sized zones and it worked as a reactive
protocol for small sized zones 16.
LINK STATE (ZHLS): It distributes the network into non-intersecting zones and every
terminal in the network consists of a zone ID and a node id by making use of
the GPS. Thus, they have two topologies at zone and network level 16.
Routing Zone of A 16
Figure 16: ZHLS
Protocol Topology 16
3. CLUSTER BASED ROUTING PROTOCOLS : Cluster
based Routing protocol is another category of VANET routing protocol in which
different vehicles forms a cluster depending upon Several characteristics like
the direction and the velocity 10.A virtual Network infrastructure is being
created via grouping of several terminals so as to increase the scalability,
also this infrastructure is important for scalability of media access
,routing protocols and the network infrastructure17.There are two main
techniques for this protocol namely COIN(Clustering for Open inter vehicular
communication network ) and LORA_CBF 10.
COIN: In Coin a structure
head is selected based on the dynamics of the vehicles as well as the driving
calculations rather than the relative mobility. It also carries the revolving
nature of the distance in between the vehicles, and Thus it can be concluded
that COIN produces much more stable architectures and overall lower overhead 17.
LORA_CBF: In this protocol, each terminal can be the cluster head, gateway or the
respective group member. Gateway can be described as a node connected to
multiple clusters. If the final location is not there then the source terminal
will send the LREQ Packet i.e. the location request packet. This part is same
as that of the AOD but the main difference lies in the LREQ and LREP packets
are dispensed only by the cluster heads and the gateways 17.
Vehicles form multiple clusters in cluster-based routing 17
1. The scalability is good in a huge
group of networks
2. Overhead is less
1. Higher latency in large dynamic
4. BROADCAST BASED ROUTING: As the name indicates,
this type of routing method broadcast the packets in the network. There is a
specified broadcast domain and the packets are available to all the vehicles
within the range of the specified domain. It is mainly used in the emergency
situations such as blockage of roads, sharing weather conditions, in case of
road accidents and for conveying announcements and advertisements 17.Flooding
is the most acceptable way to carry out a broadcast service in which each
terminal re-transmits message to all of its corresponding neighbors besides the
one from which it has received the message concerned 17.Several broadcast
based routing protocols are there such as DVCAST(Distributed Vehicular
broadcast protocol),Position aware reliable broadcasting protocol(POCA) and
Density Aware reliable broadcasting protocol (DECA ) 10.
BROADCOMM PROTOCOL: For highway environment, broad-communication emergency protocol has been
developed in which the architecture of highway is distributed into virtual
cells which show movement according to the vehicular movement 18. Furthermore,
the terminals are divided into two levels in which first consists of all the
terminals in a respective cell and the second level contains the cell
reflectors which are in the proximity to the center of the cell 17.
Broadcast routing 17
1. It is a reliable transmission
2.Overall overhead is low due to the
1. Duplicate packets can be reached to
2. Bandwidth requirement is more in this
5. GEOCAST ROUTING: Multicast packet forwarding forms the basis of these protocols. A single
source can send packets to a cluster of nodes which act as a destination. ZOR(Zone
of Relevance) :- It is defined as a particular geographical area which consists
of a group of nodes to which all the packets are transferred from a particular
starting point18.Whenever the Final destination terminal belongs to a
different ZOR then communication is done via Zone of forwarding (ZOF),thus all
the vehicles which falls into the ZOF
will transmit the data packet to the alternate ZOR’S 10.IVG
(Inter-Vehicles Geo-cast protocol) is the most renowned geo-cast protocol whose
main function is to transmit the announcement to the all the vehicles in a
particular risk prone area on delay time algorithm in a highway architecture 17.
Geo-cast routing 17
1. Overall network congestion is reduced.
2.Overhead is also reduced.
3.Reliable in case of complex network
1. Packet broadcast delay will be there
in case of network disconnection 10
CONCLUSION AND FUTURE WORK
The confluence of
Information and communication technology, computing and Tele-communication as
well as rise in the vehicular industry are encouraging the optimal utilization
of VANET technologies. In the past years, Several VANETS projects are deployed
and several standards have been made to improvise the inter-vehicular or
vehicle-to-infrastructure communications 11. A main area where research is
going on includes VANET security, QOS and to enhance the various broadcasting
techniques. The different protocols with high priority are still in
investigation phase when focussing on the security measures 11.
Also, Future work will focus on the
development of prevalent applications and context aware driver application
systems where cooperative driving techniques can be used for controlling the
traffic 18. Also, research is ongoing on emergency based Protocol to prevent
the road blockages and road accidents in case of restricted areas.
B.Ayyappan et al., “Vehicular Ad Hoc
Networks (VANET): Architectures, Methodologies And Design Issues” 2016 Second
International Conference on Science Technology Engineering and Management
Wenshuang Liang et al., “Vehicular Ad
Hoc Networks: Architectures, Research Issues, Methodologies, Challenges, and
Journal of Distributed Sensor Networks.
Maria Azees et al., “Comprehensive survey on security services in
vehicular ad-hoc networks”, IET Intell. Transp. Syst., 2016, Vol. 10, Iss. 6,
Draft guide for Wireless Access
in Vehicular Environment (WAVE) Architecture’,
http://ieeexplore.ieee.org/servlet/opac?punumber-6320593, 2012, pp. 1–74,
accessed September 2012.
Ghosh, M., Varghese, A., Kherani, A.A., et al.: ‘Distributed misbehavior
detection in VANETs’. IEEE Wireless Communication and Networking Conf., WCNC
2009, Budapest, Hungary, April 2009.
Fan Li and Yu Wang, “Routing in Vehicular Ad Hoc Networks: A
Survey”, IEEE Vehicular Technology Magazine, June 2007.
S. Abdel Hamid et al., “Routing for Wireless Multi-Hop Networks”,
Springer Briefs in Computer Science, DOI: 10.1007/978-1-4614-6357-3_2, The
Lee MJ et al., “A new taxonomy of routing algorithms
for wireless mobile ad hoc networks: the component approach”, 2006, IEEE
Communications Magazine 44 (11):116–123.
Mauve M, Widmer A, Hartenstein H (2001) A survey on position-based routing in mobile ad hoc networks. IEEE Network
15 (6):30–39. doi:10.1109/65.967595.
10. Proceedings of 2014
RAECS UIET Panjab University Chandigarh, 06–08 March, 2014 VANET Routing Protocols:
Issues and Challenges UIET, Panjab University Chandigarh, India
11. Vehicular ad hoc
networks (VANETS): status, results,and challenges Sherali Zeadally · Ray Hunt ·
Yuh-Shyan Chen ·Angela Irwin · Aamir Hassan© Springer Science+Business Media,
12. Sunder Aditya Rao1Manohara et al., “GPSR-L:
Greedy Perimeter Stateless Routing with Lifetime for VANETS”, Manipal Institute
of Technology, Manipal, IndiaIRSEEM-ESIGELEC, Technopole du Madrillet, 76800
Saint Etienne du Rouvray – France
13. M. Bakhouya et al., “Performance
Evaluation of DREAM Protocol for inter-vehicle Communication”, GSEM/SeT
Laboratory, UTBM90010 Belfort.
14. Jie Wu, “Analysis of
Topology Based Routing Protocols for Vehicular Ad-Hoc Network (VANET)”,
International Journal of Computer Applications (0975 – 8887) Volume *– No., 2014
Proceedings of the 35th Hawaii International Conference on System Sciences.
15. Marwa Altayeb1 et al., “Survey of Vehicular Ad
hoc Networks Routing Protocols”, International Journal of Innovation and
Applied Studies and ISSN 2028-9324 Vol. 3 No. 3 July 2013, pp. 829-846© 2013
Innovative Space of Scientific Research
16. Kanishka Raheja et
al., “A Survey on Different Hybrid Routing Protocols of MANET”, BRCM-CET
(Bahal), India18, / (IJCSIT) International Journal of Computer Science and
Information Technologies, Vol. 5 (4), 2014, 5512-5516.
17. Fan Li and Yu Wang, “Routing
in Vehicular Ad HocNetworks: A Survey”, University of North Carolina at Charlotte,
18. M. Bakhouya et al., “Performance
Evaluation of DREAM Protocol for Inter-Vehicle Communication”, GSEM/SeT
Laboratory, UTBM90010 Belfort.