Mobile ad hoc networks (MANETs) face different levels of challenges due to its varying mobile characteristics. The major goal of these networks is to bring the idea of mobility into real-life networks. Even though there are multitudes of applications offered by MANETs, there are certain challenges that we need to overcome. These networks are known for their infrastructureless characteristics. The nodes are free to move anywhere and hence the communications links may be broken at any moment.
There are certain characteristics which pose a sense of challenge in MANETs. It includes:
- Limitation on the size of device
- Security vulnerabilities
- Constraints on battery life
- Dynamic nature of topology
- Bandwidth issues
Autonomous terminal is one of the vital features of these networks. Each node can function both as a router and a host and hence it is impossible to clearly state specific routers in MANETs. The route selection methodologies depend mainly on the topology and the number of nodes involved. Since the network shows dynamic topology traits, diverse mobility patterns are used. Whenever new nodes come and join or existing nodes move out of the network, new routes are established. The routing algorithms adopted are determined on the basis of link layer attributes. Most of the mobile ad hoc network nodes have power constraints and less processing capabilities.
Attacks in MANETs:
Most of the attacks are caused by selfish and malicious nodes. Selfish nodes are called so because of their “selfish” properties. Attacks can be broadly classified as active and passive. Active attacks include the following types:
- Wormhole Attack
- Denial of Service
- Sybil Attack
Passive attacks include the following types of attacks:
- Traffic analysis
If the attacks require some energy to perform, it falls under the broad category of active attacks. It often involves the creation of a wrong stream or a significant change in the data stream. Let us now move on to each of the attacks in detail.
Tunneling of packets from one point to another location by an attacker is termed as wormhole attack in MANETs. Initially the attacker records the targeted packets at a specific location and then it is tunneled to another location in the network. If the control packets are captured and tunneled, it would result in the failure of routing mechanism. It is considered as a serious threat and the tunnel created between two conspiring attackers is termed as “wormhole”.
Denial of service
Denial of service refers to those attacks that are aimed at blocking access to a specific resource. The resource may be either a service or a node of the network. If there is a selfish node which denies the routing of packets to the intended destination, it can be called as a denial of service attack. In MANETs, each node is supposed to act as a router or host.
It is also called as “man in the middle” attack where a malicious node pretends its identity to change the routes between legitimate nodes in the network. Here the attacker tries to be a legitimate node of the network and it allows the malicious node to enjoy all the resources and services that are normally given to other “normal” nodes of the network.