A Multi-path Routing Optimization in MANET for Guaranteeing Bandwidth
for Real-Time Application
1
Wintwar Oo, 2Eiei Khin
1
Ph.D Student of UTYCC, Myanmar,wintwaroo@gmail.com
2
Assistant Director, AST Dept, MOST, Myanmar
Abstract-- This paper presents a multipath routing
From the routing point of view, there is no QoS
optimization mechanism for real-time applications in
support in the original protocols that use only a single
Mobile
selective parameter in route discovery [7]. So, for
Ad-Hoc
Networks
(MANETs).
Routing
optimization depends on the hop count, end-to-end
delay and bandwidth guarantee in the network. If the
optimal path is no longer to use, alternative routes will
try to use.
To provide the necessary services for a
multimedia application, considering of only one
parameter could not produce the optimal path.
Multiple relative parameters are required in route
variety of media streaming, different parameters are
discovery to support QoS. The more parameters are
combined, thus classifying the media streaming into
used, the more exactly the quality of link can be
data, audio and video.
captured.
The proposed mechanism is
However,
Different
multimedia
integrated with the Ad-hoc On-Demand Distance
applications have very diverse QoS requirements in
Vector (AODV) routing protocol.
The simulation
terms of bit rates, delay constraints, and loss
results show that the proposed system can effectively
tolerances. So, multi-parameter is excellent for QoS
reduce
the
routing
overhead,
computation
and
processing complexity by considering the dynamic
selective parameters and by using the backup routes.
demanding application, it can make the best effort
services high computational complexity and more
delay. So, the best solution is to use the different
combination of selective parameters that is suitable
Index
Terms--
Optimization;
MANET;
Multipath
QoS
AODV;
AODV;
Routing
Bandwidth
for the each application content. This paper presents
to observe most relevant route which is appropriate
Guaranteed AODV.
for the certain traffic type to provide QoS assurance
in MANET.
I. INTRODUCTION
Since multimedia applications require low delay and
II. BACKGROUND THEORY
high throughput, these application benefit from
Quality of Service (QoS) mechanisms.
As a
consequence, QoS routing is becoming a essentialtool in wireless network. Providing QoS in MANET
is challenging due to the shared and open nature of
the ad hoc network [5].
While these unique
characteristic of MANET prevent wireless networks
from providing the hard QoS guarantees, wireless
QoS mechanisms can still increase the reliability of
the communication link.
A.
TYPES
OF
AD-HOC
ROUTING
PROTOCOL
Generally, current routing protocols for MANET are
divided into Proactive, Reactive and Hybrid protocols
[12].
Proactive routing protocol is also called Table
Driven routing protocol.
In proactive routing
protocols, routes to all destinations are calculated in
the initial states and then, maintain them later by
means of periodic updates.
proactive
routing
Some of the popular
protocols
are
Destination
Sequenced
Distance-Vector
(DSDV),
Wireless
node and set up backward pointers to the source node
Routing Protocol (WRP), Cluster head Gateway
in the routing table.
Switch Routing (CGSR) and so on.
The reactive
intermediate node with a valid route to the
routing protocol is also known as on-demand routing
destination generate route reply message to the
protocol. This protocol eliminates the conventional
source. When the source gets the path, it can transfer
routing tables and consequently reduces the need for
the data.
It maintains only one path to the
updating the tables [8]. This routing protocol creates
destination.
In route maintenance phase, “Hello”
routes only when desired by the source node on
messages are used to maintain the consistency of a
demand manner. Some of the existing on-demand
previously established path. When the path breaks, a
routing protocols are Dynamic Source Routing
local repair procedure is called.
(DSR), Ad-hoc On-demand Distance Vector Routing
procedure does not work, the source finds the new
(AODV), Temporally-Ordered Routing Algorithm
route again.
(TORA) and so on.
The destination node or the
If local repair
Hybrid routing means that
combines the good properties of both proactive and
C. DISADVANTAGES OF AODV
reactive routing protocol.
Scenario 1:
In the hybrid routing
In an existing AODV, during route
protocol, the routes between near nodes settle down
discovery, the intermediate node that has a valid
and maintain by a solution of proactive type, whereas
route will generate the reply message to the source
to obtain the routes to the distant nodes, a reactive
node. This behavior results in getting the stale RREP
strategy is used. One of the popular examples of
and the source node may try to use the stale route.
hybrid routing protocol is Zone Routing Protocol
So, in the proposed system, to avoid this problem,
(ZRP).
only the destination will have the authority to
generate the Reply Message.
B. AODV ROUTING PROTOCOL
AODV is the descendant of DSDV and also attempts
Scenario 2: Original AODV uses the only one route
to improve on DSR so that the data packets do not
between source and destination in the mobile
have to contain the routes [9] [10]. AODV is well
environment.
known protocol for use by mobile nodes in MANET.
rediscovery. That will increase the routing overhead
It uses the hop count as a parameter for route
and make the performance degrading. So, to make
selection, based on Distance Vector principle. The
this problem affect less, backup routes are stored in
operations of AODV are route discovery phase, data
my system.
It will make a number of route
transfer phase and route maintenance phase.
Scenario 3: There is no consideration for QoS in the
In route discovery phase, when the node needs a
existing AODV.
route to destination and does not have one available,
considers only the hop count in finding the route. So,
route request message is broadcasted by the source
the original AODV is not suitable for multimedia
node to find a path.
application.
Node receiving this control
message updates their information for the source
The route discovery mechanism
III. RELATED WORKS
The alternative route is maintained in the ARQoS
In wired and wireless network, a lot of works have
routing table. The route was rediscovered when both
been done in providing QoS facilities.
Integrated
the primary route and the alternate route fails. It not
services (IntServ) [1] and Differentiated services
only improved packet delivery ratio but also reduce
(DiffServ) [2] are two basic architectures proposed to
the average end to end delay and the route discovery
deliver QoS guarantees in the Internet, but they are
frequency under the circumstance of high load and
not suitable for wireless ad hoc network [3]. IntServ
moderate to high mobility. The main drawback of
and DiffServ require the accurate link state and
this solution is that the accurate available bandwidth
topology information of the network. For MANET,
cannot be able to determine.
maintaining accurate routing information is very
estimation, the host can’t release the bandwidth
difficult.
immediately when a path breaks, because it does not
In listen bandwidth
know how much bandwidth each node in the broken
The QoS solutions that are suitable for MANET have
route consumes.
been proposed. K. Lee et al. [16] presented a backup
routing scheme that uses a one hop search method
M. Sedrati et al. [18] discovered all possible paths
and the rerouted path length is two-hop at maximum.
between source and destination and maintained them
It also provided the guaranteeing the bandwidth as
all during all data transfer phase. Among them, it
the service quality.
A primary route and backup
chose the shortest path according to hop count. Then,
route are created as a result of route control message
find another shortest route as a secondary path or
transmission. It had a better data delivery ratio and
backup path which is different completely from the
an improved end-to-end delay while guaranteeing the
first one.
requested bandwidth for multimedia application.
transfer using the secondary path. The purpose is to
However, it omitted how the required bandwidth of
reduce the packet loss rate caused by frequent
the
topology change and local repair procedure, and to
multimedia
application
and
the
available
bandwidth of a node are calculated.
In case of failure, data will continue
provide the continuous availability of links between
communication parties by providing the node-disjoint
In [17] and [18], backup routes were also established
secondary path. It outperforms than AODV in terms
to provide fault tolerance and to keep the continuity
of traffic control and packet loss rate under diverse
of data transmission. [17] proposed an on-demand
constraints (mobility and energy).
routing protocol To support the primary route and
disadvantage is that broadcasting also used in RREP
alternative route based on bandwidth, and delay
transmission which significantly made high routing
parameters for better QoS to improve AODV
overhead.
However, the
protocol. It discovered the route by calculating the
bandwidth requirement to find the primary route and
M. M. Thaw et al. [15] is most related to the
the alternate route from the source node to
proposed work.
destination by applying the mechanism of carrier
path for real-time traffic using hop-count, bandwidth
sense in IEEE 802.11b, Listen Bandwidth Estimation.
and mobile speed by applying fuzzy-based routing
FAODV determined the optimal
protocol over AODV.
It can transmit the data
A. OPTIMIZED ROUTING DISCOVERY
through the route with the lowest delay. However, in
To implement the proposed route discovery, several
FAODV, every node needs to compute its fuzzy cost
fields are added to the original AODV messages:
as long as it receive RREQ message between any two
Route Request message (RREQ) and Route Reply
pair nodes, So, the frequency of this computation is
message (RREP). In the route discovery, the source
slightly high, placing a heavy burden on the node.
node (S) broadcasts the RREQ message to its
The next drawback is the processing delay of route
destination. Beside the original fields defined in the
discovery because fuzzification is need at every
AODV, two more fields are added to the RREQ
intermediate node that may take long time.
message. “APP_TYPE” states the class of the
application
IV. THE PROPOSED SYSTEM
contest
The proposed mechanism consists of two main parts:
each
route
discovery.
“REQ_BW” identifies the required bandwidth of the
application content.
IMPLEMENTATION
for
The format of the extended
RREQ message is shown the Figure 1.
route discovery, and route maintenance and recovery.
The proposed mechanism works at the network layer.
Before flooding the RREQ message, firstly, the node
Before the data has arrived at the network layer, the
S adds a new route in the main routing table. In this
application layer needs to classify the multimedia
new route, source id, destination id and source
application into Data (Class 2), Audio (Class 3) and
sequence number are initialized and the rest of the
Video (Class 4). Then, the network layer is informed
fields are initialized with the default value. The node
according to the class number. If the node has already
S also needs to calculate the require bandwidth for
had a valid route to the destination for the specific
the video type and assigns in the “REQ_BW” field of
type, the node will use the existing route. Else, the
the RREQ.
network layer chooses the selective parameters for
initialized in that field. The calculation of the
route discovery according to the following Table 1
required bandwidth is as follows:
For audio and data, zero value is
and starts the route discovery process.
𝐵𝑊𝑟𝑞 =
𝑀𝑒𝑠𝑠𝑎𝑔𝑒 𝑆𝑖𝑧𝑒 (𝑉𝑖𝑑𝑒𝑜)
𝑇𝑜𝑡𝑎𝑙 𝑇𝑖𝑚𝑒 𝑇𝑎𝑘𝑒𝑛
𝑏𝑝𝑠
(1)
Table 1. Relationship between the application type
and the group of selective parameters
Type
Reverse
Hopcount
Multimedia
Class
Selective Parameters
Type
Number
Optimization
Guaranteed
Destination IP address
Parameters
Parameters
Destination Sequence Number
Hop
-
Data
Class 2
Count,
Delay
Audio
Class 3
Hop
Class 4
Hop
Delay
Originator IP Address
Originator Sequence Number
Count,
-
Count,
Bandwidth
Delay
Video
RREQ ID
TTL
APP_TYPE
REQ_BW
Figure 1. Extended RREQ message
After initializing in “REQ_BW”, RREQ message is
table, recording the information and sends back the
broadcasted. The function of the source node is as
RREP message. Note that and multiple copies of
shown in the following Algorithm 1 of the Figure 2.
RREQ messages might arrive along the different
node-disjoint paths and only the node D generates the
When receiving the RREQ message, the intermediate
fresh RREP message. Similarly, one more field is
node (I) compares the broadcast id and source id of
extended in the RREP message. “RP_APP_TYPE”
the received RREQ message with the ones in the
also specifies the multimedia class which is the same
“Broadcast_ID” table. If there is a match, the node I
field as “APP_TYPE” in RREQ message.
discards the incoming RREQs because it has already
format of the extended RREP message is shown in
accepted the one. When the node I receives the brand
the Figure 3 and the function after receiving the
new RREQ message, it makes a reverse path setting
RREQ is shown in the Figure 4.
The
which is later used for unicasting the RREP message
from the node D to the node S.
First, check the application content type
If the application content is Video
“REQ_BW” is used by the node I to compare with its
Check the required bandwidth
available bandwidth for video type application. The
If there is enough available
available bandwidth is measured through Hello
bandwidth at the source node
Bandwidth Estimation method [11] [14].
Hello
Broadcast the RREQ with
Bandwidth Estimation method is chosen because,
bandwidth constraint
using this approach, the node can release the
Else
bandwidth immediately when a route breaks. In this
Terminate the route discovery and
approach, the sender’s current bandwidth and the
Exit
sender’s one-hop neighbors’ current bandwidth usage
End If
is piggybacked onto the “Hello” message. Each node
estimates its available bandwidth based on the
information provided in the “Hello” message. If the
Else
Broadcast the RREQ
End If
requirement can be met, the intermediate node
Figure 2. The algorithm of the function of the
rebroadcasts the RREQ message until it reaches the
source node
intended destination (D). If the requirement cannot
be satisfied, the node discards the RREQ message
Type
Reverse
Hopcount
and does nothing further. For the audio and data
Destination IP address
type, the node I just rebroadcasts the RREQ.
Destination Sequence Number
Rebroadcasting is done after decrementing the one to
Originator IP Address
the time to live (TTL) of RREQ message.
Originator Sequence Number
RP_APP_TYPE
Upon receiving the RREQ messages, the node D
inserts an entry about the RREQ in the main routing
Figure 3. Extended RREP message
𝐸𝑛𝑑𝑡𝑜𝐸𝑛𝑑 𝐷𝑒𝑙𝑎𝑦 = 𝐿𝑖𝑛𝑘𝐷𝑒𝑙𝑎𝑦 + 𝑁𝑜𝑑𝑒𝐷𝑒𝑙𝑎𝑦
Step 1: If application content is “VIDEO”
If (Node’s Available_Bandwidth <
= ∑𝐸𝑖=1 𝑙𝑖𝑛𝑘_𝑑𝑒𝑙𝑎𝑦𝑖 + ∑𝑁
𝑗=1 𝑛𝑜𝑑𝑒_𝑑𝑒𝑙𝑎𝑦𝑗
(2)
Content’s Required_Bandwidth)
After that, the optimal value for each route is
Discard the RREQ message and Exit.
calculated using the weighted-sum as follows:
End If
End If
𝐶𝑜𝑠𝑡𝐹𝑢𝑛 = 𝐹(ℎ𝑜𝑝_𝑐𝑜𝑢𝑛𝑡, 𝐸𝑛𝑑_𝑡𝑜_𝐸𝑛𝑑 𝑑𝑒𝑙𝑎𝑦)
Step 2: If the incoming RREQ is new
𝐶𝑜𝑠𝑡𝐹𝑢𝑛 = 𝛼𝐹1 + 𝛽𝐹2
Set the backward pointer to the Source S
(3)
Add the necessary information to the
This equation is also called the multiple objective
RREQ
optimization function. In this objective function, the
Else
objective function of hop count is denoted as F1 and
Discard the RREQ and Exit.
End If
the objective function of end-to-end delay is denoted
Step 3: If the received node is the intended
as F2. Hopcount function is assigned a weight value
destination
(𝛼) and end-to-end delay function is assigned a
weigh (𝛽). The coefficient α and β are interpreted as
Send the corresponding RREP
Else
the relative emphasis of one objective as compared to
Broadcast RREQ message to
another.
its neighbors
testing by varying a number of constant value pair.
These parameters are determined from
When determining these values, end-to-end delay is
End If
given more pressure on but not much different with
Figure 4. The function of a node after receiving
the RREQ message
hopcount for the multimedia application. At the β
value is 0.6 and α is 0.4 (1-β = 1-0.6 = 0.4), the
each
system can produce the optimal performance of the
intermediate node makes a forward path setup for the
QoS system, hence α and β are set 0.4 and 0.6,
data transmission and traversed the RREP on the
respectively.
When
receiving
the
RREP
message,
reversed path to the destination.
If the RREP message arrival is the first time, the node
For the source node, it calculates the optimal value
S stores the route entry in the main routing table. If
for each path. Path-optimization is determined by the
the RREP message arrival is not the first time, the
combined state over all links of each path. Path-
node S makes a comparison with the one in the main
optimization is based on two parameters: hopcount
routing table and stores the smaller optimal valued
and end-to-end delay. Hopcount is directly obtained
route in main and the other in backup routing table.
from the RREP message.
Then, the source node makes the data transmission
End-to-end delay is
calculated by adding the total link delay and total
node delay by using the following equation:
using the primary route in the main routing table.
B. ROUTE MAINTENANCE AND RECOVERY
links broken. Consequently, using too many routes
In MANET, the route may no longer be used due to
for backup is not suitable when the nodes are moving
the link failure or node failure. Each node in the
frequently. That’s why it is necessary to define a
network monitors its neighbors by send Hello
limit on the backup routes.
Message periodically to maintain the route.
If a
number of backup routes is investigated from various
node did not receive the Hello message during the
the experiments. It is found that the best suitable
predefined time, the node knows that there is a
backup path number is 2. By using the maximum
problem in the route and generates the Route Error
backup routes up to 2, this proposed system is highly
(RERR) message and sends to the source of the route.
adapted to network changes and it has a high
When the node S receives the RERR message, it will
convergence. And that’s why, one primary route and
need to use another route. So, the node S finds the
two backup routes are used in this system to provide
backup route in the backup routing table. If there
fault tolerance and robust to failure.
So, the effect of the
exits, the primary route is replaced with the backup
route and remove the backup route from the backup
Table 2. Extended fields in the routing table
table. If there is no backup route or all the backup
Field Name
Type
Definition
routes are invalid, the node S will start the route
rt_app_type
Integer
Application type field
(u_int8_t)
for
discovery again.
each
transaction
C. ROUTING TABLES IN THE PROPOSED
pair
SYSTEM
destination
In this proposed system, two routing tables called
main and backup routing tables are used.
rt_cost
Double
source
a
and
whole route
rt_delay
Double
Delay value field of the
and backup routing tables are used to store the
backup routes for nodes in the network. Both routing
between
Cost value field of the
Main
routing table is used to store the current using routes
of
traffic
whole rout
rt_src
Network
Route source field to
tables have the exactly same structure. To implement
Address
define the source node of
the proposed system, some fields are extended in the
(nsaddr_t)
the transmission
original AODV routing table as following Table 2.
V. SIMULATION AND PERFORMANCE
The next important point about the proposed system
ANALYSIS
is how many routes should be used in each route
To evaluate the performance of the proposed system,
discovery. As mentioned above, using backup routes
several wireless ad hoc network topologies are
can reduce the route discovery time and can reduce
simulated. Note that the proposed system is denoted
the propagation of the route request. However, in a
as
mobility environment, Rate of link failure or repair
simulations are conducted on NS2 (NS 2.34) network
may be high when nodes move fast. As a result, the
simulator [4] [6] under OpenSUSE (11.0) Linux
backup path can also become invalid and may be all
platform.
Content-Based
AODV
(CBAODV).
All
In order to make fair comparison,
protocols are simulated under identical loads and
graphical representation of the simulation window is
environmental conditions.
shown the Figure 5.
UPD is considered as
transport agent and CBR for data, AUDIO and
VIDEO are considered as traffic generators.
A
number of different scenario files with varying
movement pattern and traffic loads are pre-generated
by random nature.
The mobility model uses the
random waypoint model in a rectangular. Table 3
gives a summary of the common parameters that are
going to use in the simulations.
Table 3. Summary of common parameters
Parameters
Values
Simulator
NS-2.34
Routing Protocol
AODV, CBAODV
Simulation time
200s
Figure 5. Simulation Window with 100 nodes in
Application Traffic
CBR, AUDIO,VIDEO
NS2
Number of Nodes
25, 50, 75, 100, 125
Packet Size
512
Mac Protocol
Mac/802.11
Transmission rate
4 Packets /s
audio, video and data are investigated using 25 nodes
Maximum speed
20m/s
in a 800m x 800m. The total number of connection is
No of Connections
12 or 20
12 which mean 12 CBR connections or 12 AUDIO
Movement Model
Random Waypoint
connections or 12 VIDEO connection or All
Paused time
0,5,10,15,20,25,30
connections which means (4 CBR and 4 AUDIO and
A.
EXPERIMENTAL
RESULTS
OF
SIMULATION 1
In the simulation 1, the effect of each traffic type
4 VIDEO connections).
The performance of the proposed system is measured
in terms of:
The performance is
measured in terms of routing overhead, packet
delivery fraction, delay and packet drop ration which
are shown in Figure 6, Figure 7, Figure 8 and Figure

Routing Overhead
9 respectively. These figures show that the proposed

Average End-to-end Delay
system has the better delay, packet delivery ratio and

Packet Delivery Fraction
packet drop ratio.

Packet Drop Ratio
because when the node number is fewer, it will make
But RO is significantly high
To evaluate the performance, the output trace file of
route discovery frequently and it is more likely to
the simulation is parsed to extract the required
occur that backup routes are invalid.
information with the help of “awk” program. The
Figure 6. Delay vs traffic type pattern
Figure 9. Packet delivery ratio vs traffic type
pattern
B.
EXPERIMENTAL
RESULTS
OF
SIMULATION 2
In this simulation 2, delay and routing overhead of
the proposed system is evaluated with 20 connections
under the different paused time for the node 25. In
the figure 10, it can be seen that delay of the
proposed system is higher than the original AODV at
the paused time 15, 20, 25 and 30. But, the proposed
Figure 7. Packet deliver fraction vs traffic type
pattern
system has the lower end-to-end delay than AODV at
the paused time 0, 5, 10.
However, the routing
overhead of the proposed system is slightly higher
than the original AODV at the paused time 0 and 5 in
the Figure 11.
Figure 8. Routing overhead vs traffic type pattern
Figure 10. End-to-end delay vs paused time for 25
nodes
This is due to the use of the less amount of node in
the mobility environment. Because of less node and
mobility, the frequency of route discovery is higher.
So, it can conclude that the proposed system is more
efficient when the node mobility environment.
However, it is found that although the proposed
system is not suitable the network where the node
number is small, the system do the best it can when
the environment is continuously changing.
Figure 12. End-to-end delay vs paused time for 50
nodes
Figure 11. Routing overhead vs paused time for 25
nodes
C.
EXPERIMENTAL
Figure 13. Routing overhead vs paused time for 50
RESULTS
OF
SIMULATION 3
In the simulation 3, delay and routing overhead of the
proposed system is evaluated with 20 connections
under the different paused time for the node 50.
Here, the pattern of end-to-end delay and routing
overhead are almost similar to simulation 2 as shown
in Figure 12 and Figure 13. Except the cases of
paused time 10, 15 and 30, most of the values of the
proposed system have a higher end-to-end delay than
the AODV but, in here, not much difference.
Similarly, in the routing overhead, the proposed
system has the greater values except the paused time
5 which has the nearly same value.
nodes
It is concluded that there are two main factors which
affect the performance of the system from simulation
1 and 2. The first reason is the number of nodes. If
the number of nodes are small and the network is
moving continuously, link breaks occurs frequently.
As a result, it is difficult for using the backup routes
because the backup routes can also be broken
because of the mobility.
So, applying the route
discovery many times makes the system more
performance degrading.
The second reason is the
number of traffic connection. In this scenario, the
number of traffic connections makes the burden for
the 50 nodes and 25 nodes. To sum up, the proposed
system is not performed well when the node number
is small or when the traffic connections are too many
the routing overhead is increased, whereas the load of
for the node number or in both conditions.
CBAODV is sharply reduced using the backup paths.
So, the proposed system is appropriated when the
D.
EXPERIMENTAL
RESULTS
OF
node number increased in the mobility environment.
SIMULATION 4
The simulation 4 also evaluates delay and routing
E.
overhead of the proposed system with 20 connections
SIMULATION 5
under the different paused time for the node 75 in the
The simulation 5 also evaluates delay and routing
area of 1000m x 1000m. In this simulation, it is
overhead of the proposed system with 20 connections
noticed that CBAODV shows the lowest end-to-end
under the different paused time for the node 100 in
delay and routing overhead than the original AODV
the area of 1000m x 1000m. In this Figure 16, most
as shown in the Figure 14 and Figure 15.
of the end-to-end delay values of the proposed
EXPERIMENTAL
RESULTS
OF
system are higher than the AODV except the pause
time 10 which has the similar structure. The most
obvious delay differences are found in the case of
paused time 0, 15, and 20. For the routing overhead
comparison between the AODV and the proposed
system, CBAODV, the routing overhead of the
AODV is significantly higher than the proposed
system when the paused time 0, 15, 20 and 30 as
shown in the Figure 17.
Figure 14. End-to-end delay vs paused time for 75
nodes
Figure 16. End-to-end delay vs paused time for
Figure 15. Routing overhead vs paused time for 75
nodes
The reason is that in the AODV, the more the nodes
are mobility, the more the link breaks occur. The
frequency of route discovery increases. As a result,
100 nodes
the node are 25 and 50 as shown in the Figure 19.
However, the proposed system is outperformed when
the nodes are 75, 100 and 125 which are lower than
27%, 52% and 35% respectively.
Figure 17. Routing overhead vs paused time for
100 nodes
F.
EXPERIMENTAL
RESULTS
OF
SIMULATION 6
In the simulation 6, the performance is tested with
different node number under the fixed paused time
Figure 19. Routing overhead vs number of nodes
(p0) which is the continuous movement in terms of
routing overhead, delay, packet delivery fraction and
packet drop ratio.
From the Figure 20, packet delivery of CBAODV is
15%, 27% and 14% less than packet delivery of
AODV at the number of node 25, 50 and 75. The
In the Figure 18, the delay of CBAODV approach is
higher when the node is 50, but it has a significantly
lower delay when nodes are increased up to 75. And
then both approaches have the similar delay values
when the nodes are 100 and 125.
Figure 18. End-to-end delay vs number of nodes
packet delivery fraction of CBAODV is slightly
greater than AODV at the nodes 100 and is almost
similar at node 125.
The packet drop Ratio is
inversely proportional to the packet delivery fraction
as shown in the Figure 21.
Figure 20. Packet delivery fraction vs number of
nodes
It can be found that the routing overhead of the
CBAODV is slightly higher than the AODV when
The obvious advantage of the proposed system is that
within one route discovery time, at least one path is
obtained if the destination is accessible. In ordinary
AODV, 1st route discovery cannot obtain route
because destination accept only one route and this
route may become link break before the reply
sending.
VI. CONCLUSION
Figure 21. Packet drop ratio vs number of nodes
In this paper, a new mechanism is presented to make
As a conclusion, the simulation results will show that
the proposed routing scheme has a, better average
packet delay, improved routing overhead, similar
packet delivery ratio and similar packet drop ration.
The proposed system can work the best at the node
AODV more robust and efficient. The purpose of the
new mechanism is to find a feasible path between
source and destination, which satisfies the QoS
requirements for each connection. The idea of using
dynamic parameter is able to find the most
appropriate
number 100 at the mobility environment.
route
for
particular
application.
Multipath routing also provides the fault tolerance.
G. RESULT ANALYSIS AND BENEFIT OF
So, this mechanism gets the better performance and
lower computational complexity than the original
THE PROPOSED SYSTEM
The performance study of the proposed with AODV
under the mobility and traffic scenarios reveals the
AODV protocol. The improvement in performance
shows the effectiveness of this proposed system.
proposed system offers a significant reduction in
routing overhead.
It also offers better or similar
Packet Delivery Ratio and dropped packets. But the
number of delay increases in the proposed system
under the condition of lower node number. However,
when the number of node is increasing, there is no
significant difference in delay of two protocols. By
using the variables dynamically, the proposed can
reduce the unnecessary processing overhead.
By
using the backup route, we can eliminate the amount
of messages that need for route discovery. So, both
communication overhead and processing overhead
can be reduced.
By using the maximum backup
routes up to 2, this proposed system is highly adapted
to network changes and it has a high convergence.
However, to provide the QoS, the researchers work
on three main fields: (1) QoS Routing Protocol, (2) a
resource reservation scheme and (3) a QoS capable
medium
access
control
(MAC)
layer
[13].
Combining these three components provide the
complete QoS solution for a particular system. In
future, the effective resource reservation mechanism
and QoS capable MAC layer are planned to add to
the existing system to provide the complete ondemand QoS routing protocol. Moreover, due to the
nature of ad hoc networks, QoS cannot be guaranteed
for a long time because of the link quality variation.
Methods to detect and report changes in the
connection quality should also be investigated in the
future.
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