Packet Forwarding

Vehicular ad hoc networks (VANET) play an important role in future car-to-car communication systems and related applications like self-organizing traffic information systems (SOTIS), which are based on broadcast/geocast transmission schemes. Congestion control for VANETs has not been studied thoroughly so far - but this feature is extremely necessary for VANET applications and network performance. Due to the high mobility and the resulting highly dynamic network topology, congestion control needs to be performed in a decentralized and self-organized way, locally in each VANET node. This paper presents a novel concept for utility-based congestion control and packet forwarding in VANETs. The control algorithm uses an application-specific utility function and encodes the quantitative utility information in each transmitted data packet in a transparent way for all users within a local environment. A decentralized algorithm then calculates the "average utility value" of each individual node based on the utility of its data packets and assigns a share of the available data rate proportional to the relative priority. For performance evaluation, the proposed decentralized utility-based packet forwarding and congestion control (UBPFCC) is implemented on top of the IEEE 802.11 MAC protocol. Network simulations including vehicular mobility models demonstrate that UBPFCC avoids the typical starvation of some nodes inside the network and shows a significant increase of efficiency in information dissemination and fairness.

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.

Multi-protocol label switching (MPLS) has begun to deploy in the Internet backbone to support service differentiation and traffic engineering. In recent years, there has also been an interest to extend the MPLS capability to the wireless access networks. In this paper, we provide an overview of the MPLS-based micro-mobility management including label switching path setup, packet forwarding, handoff processing, and

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.

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