Packet Forwarding

In mobile IP based networks, most of the packet drops occur due to mobile handoff from one sub-network to another sub-network or larger delays in between sender and receiver due to encapsulation and tunnelling of packets. Packet loss during the handoff operation in mobile IP with route optimization and smooth handover will degrade the performance of Transmission Control Protocol (TCP). To prevent performance degradation due to mobile handover packet drops, a number of packet buffering and packet forwarding mechanisms have been proposed. However, mobile user continually change its point-of-attachment and can sometimes move into congested base station of foreign agent sub network, its buffered forwarded packets are likely to be dropped at the new base station. This can lead to decrease in congestion window size at the sender TCP, which will severely degrade the performance of TCP even though there is no congestion within the network. In this approach, hardware resources (packet buffers) are efficiently utilized, at the same time performance degradation of TCP due to congested base station of current mobile node is minimized through packet buffers, markers and with modification in Mobile IP binding update message.

Nowadays, internet plays a vital role in our day to day activities such as online transactions, online shopping and other communications infrastructure; due to slow convergence of routing protocols after network failure become a budding problem. To guarantee fast recovery from link and node failure in networks, we propose a new recovery scheme called Multiple Routing Configuration (MRC). Our proposed scheme guarantees recovery in all single failure and mechanism to handle both link and node failures without knowing the actual cause of the failure. In this paper we present MRC, and examine its performance with respect to load distribution after a failure. We also present how an estimate of the traffic demands in the network can be used to improve the distribution of the recovered traffic, and thus reduce the chances of congestion in the network.

IEEE 802.11 lacks of the capability to support quality of services such as multimedia and real-time traffic properly. This paper presents a simple approach to enhance the multimedia real-time performance over the 802.11 WLAN by implementing a Quality Of Service Manager (QoSM) for differentiating services with two queues on top of the 802.11 medium access controller. With slow decrease of

Because sensor nodes operate on power limited batteries, sensor functionalities have to be designed carefully. In particular, designing energy-efficient packet forwarding is important to maximize the lifetime of the network and to minimize the power usage at each node. This paper presents a geographic energy-aware multipath stream-based (GEAMS) routing protocol for WMSNs. GEAMS routing decisions are made online, at each forwarding node in such a way that there is no need to global topology knowledge and maintenance. GEAMS routing protocol performs load-balancing to minimize energy consumption among nodes using twofold policy: (1) smart greedy forwarding and (2) walking back forwarding. Performances evaluations of GEAMS show that it can maximize the network lifetime and guarantee quality of service for video stream transmission in WMSNs.

A mobile ad hoc network (MANET) is a temporary infrastructureless network, formed by a set of mobile hosts that dynamically establish their own network on the fly without relying on any central administration. Mobile hosts used in MANET have to ensure the services that were ensured by the powerful fixed infrastructure in traditional networks, the packet forwarding is one of these services. The resource limitation of nodes used in MANET, particularly in energy supply, along with the multi-hop nature of this network may cause new phenomena which do not exist in traditional networks. To save its energy a node may behave selfishly and uses the forwarding service of other nodes without correctly forwarding packets for them. This deviation from the correct behavior represents a potential threat against the quality of service (QoS), as well as the service availability, one of the most important security requirements. Some solutions have been recently proposed, but almost all these solutions rely on the watchdog technique as stated in S. Marti et al. (2000) in their monitoring components, which suffers from many problems. In this paper we propose an approach to mitigate some of these problems, and we assess its performance by simulation.

We propose a path unaware layered routing protocol (PULRP) for dense underwater 3D sensor networks. An uplink transmission is considered, where a set of underwater sensor nodes report events to the sink node. PURLP algorithm consists of two phases. In the first phase (layering phase), a layering structure is presented which is a set of concentric spheres, around a sink node. The radius of the concentric spheres is chosen based on probability of successful packet forwarding as well as packet delivery latency. In the second phase (communication phase), we propose a method to choose the intermediate relay nodes and an on the fly routing algorithm for packet delivery from source node to sink node across the chosen relay nodes. The proposed algorithm, PULRP finds the routing path on the fly and hence it does not require any fixed routing table, localization or time synchronization processes. Our findings show that the proposed algorithm has a considerably better successful packet delivery rate compared to the under water diffusion (UWD) algorithm proposed in the paper by Lee et al. (2007) and Dijkstra's shortest path algorithm. In addition the delay involved in PULRP is comparable with that of UWD.

We present an interesting application of network processors in the field of network security. Specifically, we report on the design and implementation of a high- speed prototype to provide packet-filtering functions to mitigate distributed denial of service (DDoS) attacks that target network resources. The effects of DDoS attacks are felt when network or host resources are used illegitimately at the

A recent surge of research on vehicular ad hoc networks (VANETs) has given us new opportunities and challenges. Aside from safety-related applications, commercial applications also find their way to fully utilize these networks. One of the promising applications is the dissemination of commercial advertisements over VANETs. However, there are uncooperative vehicles that may disrupt the spreading of these advertisements. To encourage cooperation, we want to address proper incentives and security measurements. In this paper, we use Reed-Solomon codes (RS-codes) to construct our incentive scheme and enhance its security by introducing one discrete logarithm representation problem. Our construction yields a secure and practical commercial advertisement dissemination scheme over VANETs.

Routing in ad hoc network is a great problematic, since a good routing protocol must ensure fast and efficient packet forwarding, which isn't evident in ad hoc networks. In literature there exists lot of routing protocols however they don't include all the aspects of ad hoc networks as mobility, device and medium constraints which make these protocols not efficient for

In this paper we discuss the MANIAC Challenge, a cooperative and competitive approach to MANET networking research. Our goal was to create an opportunity for researchers to come together and compete in a MANET-based competition where points were awarded for received traffic and deducted for use of node resources, including packet forwarding. Using software we created, each team built a participation strategy that allowed them to decide how much they would participate in forwarding traffic for other nodes. This exercise turned out to be a resounding success and a wealth of data was gathered about traffic patterns, network behavior, node behavior, and the impact of node participation strategies on the MANET. The major observations of this work are that location and hardware can affect node performance, node participation can affect the larger network in some circumstances, and node mobility patterns can vary based on the goal of the node.

In this article, a new game theoretical method is proposed to model packet forwarding in relay networks. A simple case of relay network that consists of a source, a relay and a destination node communicating on a common channel is considered. A stationary Markovian game model is utilized to optimize the system performance in terms of throughput, delay and power consumption cost. Both cooperative and non-cooperative solutions are provided for this model. Best strategy set taken by players as well as system performance is studied for different system parameters. Also, the proposed method is extended to model a more general case of Ad-hoc networks considering different packet error rates in case of collision occurrence that improves the system performance further. Simulation results show that performance of the non-cooperative solution, in which players do not require to know each other’s selected strategy, asymptotically approaches the cooperative system performance. Hence, the proposed model with non-cooperative solution is an appropriate method to apply in practical Ad-hoc networks.