The rapid evolution in the field of mobile computing is driving a new alternative way for mobile communication, in which mobile devices form a self-creating, self-organising and self-administering wireless network, called a mobile ad hoc network. Mobile Ad Hoc networks includes to be one of the raised area of domains that S-LOGIX offers to work on projects with.
RuIts intrinsic flexibility, lack of infrastructure, ease of deployment, auto-configuration, low cost and potential applications make it an essential part of future pervasive computing environments. As a consequence, the seamless integration of mobile ad hoc networks with other wireless networks and fixed infrastructures will be an essential part of the evolution towards future fourth generation communication networks.
Extension to the existing protocols or modeling a new protocol in NS2 for MANET can be done in the following aspects. The protocols are developed as C++ files and the dependent files are modified in the ns- allinone package. The directory structure of the newly added files is mentioned in Makefile. Then NS is rebuilt using Linux utility tool make. Simulation can be carried out by mentioning the newly developed protocol in the TCL configuration file.
Extensions can be done at each layer as follows.
Implementation solutions at Physical and MAC layer in MANET using NS2
In Physical layer, files for directional antenna can be patched and transmission power control techniques can be done for the solutions related to transmission range adjustment.
In MAC layer, multi-channel and multi-interface patching can be done to apply channel tuning techniques and backoff methods.
Implementation solutions at the Network layer in MANET using NS2
In Network layer, the protocols such as AODV, DSR, DSDV, TORA, AOMDV, OLSR, FSR, GPSR, POR, CBRP, ZRP, etc. can be modified for various solutions related to QoS, Security and so on.
Various attacks such as black hole, gray hole, wormhole, flooding, misrouting, modification, jellyfish and other routing attacks can be modeled by modifying the routing behavior of the attacker nodes in corresponding routing protocol files.
Attack detection techniques such as applying overhearing can be integrated into protocol functionality.
Implementation of opportunistic routing can be done by exploiting overhearing functionality and data cache maintenance at the node by modifying GPSR routing protocol.
Implementation solutions at Transport layer in MANET using NS2
In Transport layer, the protocols such as TCP and UDP can be modified for performance improvement solutions related to data flow control.
Implementation solutions at Application layer in MANET using NS2
In Application layer, security algorithms such as RSA, ECC, HMAC can be integrated for security related solutions.
Implementation solutions in Cross layer in MANET using NS2
Parameters such as signal strength, energy, queue size, packet priority can be attached in the packets so that it can be accessed in protocols of other layers to develop the cross layer solutions.
Performance Analysis of MANET using NS2
Network Performance in MANET varies depends on various network characteristics.
Impacts in Network Performance
Impact with respect to node mobility
Varying
– Speed
– Pause time
– Type of mobility model (Random Way Point, Random Walk, etc)
Impact of Network traffic
Varying
– Number of communication flows
– Data rate of each flow subject to the constraints of the number of channels and interfaces, and bandwidth of the channel
Impact of node density
Varying
– Number of nodes in the network
– Area of the network
– Distance between source and destination
Impact with respect to physical layer properties of the node
Varying
– Communication range
– Sensing range
– Transmission power
– Battery energy
– Type of the antenna- omni or directional antenna
Impact in Attack scenarios
Varying
– Number of attackers
– Percentage of malicious behavior
Impact with respect to selection of the protocol at each layer
The impact can also be observed with the selection of the protocol at each layer. One example of this is with the same scenario, the choice of routing protocol in network layer such as AODV, DSR, DSDV, TORA, and AOMDV can make the difference in results.
Impact with respect to protocol specific feature
Variation of protocol specific feature also has an impact on performance. One such kind of variation is evaluating TCP protocol for various congestion window size parameter values.
Performance Metrics in MANET Using NS2
Packet Delivery Ratio (PDR)
Throughput
Average End to End Delay
Routing Overhead
Control Overhead
Storage overhead
Packet Loss
Hop count
Attack detection accuracy
Attack detection time
False Alarm
Energy consumption
Residual energy
There are numerous Impacts and Metrics depends on the proposed approach and the network scenario apart from the aforementioned things. AWK script for these metrics can be applied to process the trace file that consists of the information such as event time, event type, node ID, packet sequence number, type and size of the packet, the layer at which the event occurs, reason for packet drop, remaining energy of the nodes, and TTL. The results from the execution of AWK script can be plotted as Xgraph in NS2 for the purpose of self or comparative protocol analysis.