Abu Zafar M. Shahriar

Route optimization in network mobility: Solutions, classification, comparison, and future research directions

Network mobility (NEMO) handles mobility of a set of mobile nodes in an aggregate way using one or more mobile routers. NEMO introduces several advantages, such as reduced signaling, increased manageability, reduced power consumption and conservation of bandwidth when compared to individual host mobility. NEMO Basic Support Protocol (BSP), the IETF standard for NEMO, suffers from a number of limitations, like inefficient route and increased handoff latency. Most of the recent research efforts on NEMO have concentrated on solving the problem of inefficient route resulting in several route optimization schemes to solve the problem. To choose a route optimization scheme, it is very important to have a quantitative comparison of the available route optimization schemes. The objective of this article is to survey, classify and compare the route optimization schemes proposed in the literature over the last five years. We classify the schemes based on the basic approach for route optimization, and compare the schemes based on protocol overhead, such as header overhead, amount of signalling, and memory requirements. We conclude that performance of the classes of schemes has to be evaluated under criteria such as available bandwidth, topology of the mobile network and mobility type.

A multiprocessor based heuristic for multi-dimensional multiple-choice knapsack problem

Abstract This paper presents a multiprocessor based heuristic algorithm for the Multi-dimensional Multiple Choice Knapsack Problem (MMKP). MMKP is a variant of the classical 0–1 knapsack problem, where items having a value and a number of resource requirements are divided into groups. Exactly one item has to be picked up from each group to achieve a maximum total value without exceeding the resource constraint of each type. MMKP has many real world applications including admission control in adaptive multimedia server system. Exact solution to this problem is NP-Hard, and hence is not feasible for real time applications like admission control. Therefore, heuristic solutions have been developed to solve the MMKP. M-HEU is one such heuristic, which solves the MMKP achieving a reasonable percentage of optimality. In this paper, we present a multiprocessor algorithm based on M-HEU, which runs in O(T/p+s(p)) time, where T is the time required by the algorithm using single processor, p is the number of processors and s(p), a function of p, is the synchronization overhead. We also present the worst-case analysis of our algorithm, the computation of the optimal number of processors as well as the lower bound of the total value that can be achieved by the heuristic.

Mobility management protocols for next-generation all-IP satellite networks

To provide ubiquitous terrestrial Internet coverage mobility and Internet-based access to data generated by satellites, there is a strong desire to integrate the terrestrial Internet and satellite networks. This requires satellites that are based on IP for communications. Rotation of low Earth orbit satellites around the Earth results in communicating with different ground stations over time, and requires mobility management protocols for seamless communication between the Internet and satellite networks. In this article we provide a comprehensive summary and comparison of state-of-the-art research on mobility management schemes for satellite networks. The schemes are based on network and transport layers for managing host and network mobility. This article clearly indicates the aspects that need further research and which mobility management schemes are the best candidates for satellite networks.

Performance of Prefix Delegation-Based Route Optimization Schemes for NEMO

A number of prefix delegation-based schemes have been proposed in the literature to solve the route optimization problem in NEMO, where a group of hosts move together as a mobile network. The route optimization solutions generate different amounts of overheads that depend on the characteristics of the mobile network and mobility parameters. The overheads limit performance, giving rise to the need to carry out a comparative performance evaluation of the schemes to aid in the selection of a scheme; currently there is no tool which can aid in the selection. The objective of this paper is to develop analytical models to allow comparison among the schemes, and selection of an appropriate scheme for a given mobility scenario and mobile network characteristics. Results show that a single scheme does not suit all mobility scenarios and network characteristics. Selection of a scheme should, therefore, consider adaptation to the scenario and characteristics. The schemes could also be extended to dynamically adapt to changing scenario and characteristics.

Evaluation of Prefix Delegation-Based Route Optimization Schemes for NEMO

Among the schemes, proposed in the literature to solve the route optimization problem in NEtwork MObility (NEMO), the prefix delegation-based schemes perform better than other schemes. Depending on the way the prefix are delegated, the prefix delegation-based schemes result in difference in performance under different speed at various distance from the home network (network to which mobile network usually belongs). Therefore, there is a need to evaluate the performance of individual prefix delegation-based scheme to find an appropriate scheme based on speed and distance from home network. In this paper, we identify the differences of the refix delegation-based schemes using simulation. Results reveal that performance of the schemes depends on speed of the network and distance from home network.

A Cost Analysis Framework for NEMO Prefix Delegation-Based Schemes

Network Mobility (NEMO) efficiently manages the mobility of multiple nodes that moves together as a mobile network. A major limitation of the basic protocol in NEMO is the inefficient route between end hosts. A number of prefix delegation-based schemes have been proposed in the literature to solve the route optimization problem in NEMO. Approaches used by the schemes trade off delivery of packets through the partially optimized route with signaling and other processing overheads. Cost of delivering packets through the partially optimized route along with signaling and processing cost need to be measured to find out the gain from tradeoff. However, cost analysis performed so far on NEMO protocols consider only the cost of signaling. In this paper, we have developed analytical framework to measure the costs of the basic protocol for NEMO, and four representative prefix delegation-based schemes. Our results show that cost of packet delivery through the partially optimized route dominates over other costs. Therefore, optimizing the route completely is preferable to reduction of signaling as far as cost of network mobility is concerned. Our cost analysis framework will help in decision making to select the best route optimization scheme depending on the load imposed by the scheme on the infrastructure.

Network Mobility in satellite networks: architecture and the protocol

Mobility management is required to ensure the session continuity for multiple Internet Protocol-enabled devices onboard a satellite that hands off between ground stations. Network Mobility NEMO can efficiently manage the mobility of multiple Internet Protocol-enabled devices that are connected as a mobile network. However, existing mobility management solutions for satellite networks are unable to route through intermediate satellites links when a direct connection with a ground station is lost. We proposed an architecture of NEMO in satellite networks with routing through multiple satellite links using nesting, where a mobile network connects to another mobile network. However, NEMO Basic Support Protocol can be inefficient in satellite networks because of poor nesting formation leading to the routing loop, inefficient routes, and overloaded links. We extended NEMO Basic Support Protocol for the efficient use in satellite networks by augmenting it with a decision criteria for the nesting. Results verify that the extended protocol ensures loop-free and continuous connection despite the loss of direct connection to the ground and provides an insight on how to form the nested NEMO to avoid overloading. The architecture and the extended NEMO protocol can be used for the efficient and continuous transfer of data from satellite networks to the ground. Copyright

Performance of Prefix Delegation-Based Route Optimization Schemes: Intra Mobile Network Case

Among the route optimization schemes in NEtwork MObility (NEMO), the prefix delegation-based schemes perform better than other schemes. Since the prefix delegation-based schemes are designed for communication between a mobile network and a wired network, they lack evaluation for the case of intra mobile network communication involving MIPv6 incapable hosts in a mobile network. We evaluate prefix delegation-based schemes to reveal their inefficiencies for the case where both the communicating hosts are mobile and MIPv6 incapable, propose extensions, and compare them. Since both the communicating hosts are mobile, handoff latency in extended schemes are large resulting in significant performance loss when the speed of the mobile network is high. Results reveal that the effect of speed of the mobile network dominates the performance in such cases. We conclude that for slow moving mobile networks, extended schemes are preferable.

Performance evaluation of NEMO in satellite networks

Network mobility (NEMO) protocols can be used to manage aggregate mobility of multiple IP-enabled devices on-board a Low Earth Orbit satellite (a mobile network on-board). NEMO protocols enjoy several performance advantages, such as reduced signaling, increased manageability and conservation of satellite link bandwidth as compared to host mobility protocols for individual devices. In addition, NEMO protocols can provide continuous connectivity at upper layers using nested NEMO (a mobile network attached to another) during unavailability of ground stations where as connection would terminate if host mobility protocols were used. Therefore, NEMO protocols needs to be evaluated in space. We propose an architecture for NEMO in space, where the devices are connected together using an on-board local area network . The architecture includes nesting where a mobile network ontwork. The architecture includes nesting where a mobile network on-board a satellite can attach to another. We evaluated NEMO protocols for the architecture using a space friendly data transfer protocol called Saratoga because widely used protocols like TCP is not space friendly. Simulation based performance evaluation shows continuity of connections at upper layers and performance superiority of Saratoga to TCP for NEMO in space.

Performance of prefix delegation based route optimization schemes for NEMO

A number of prefix delegation-based schemes have been proposed in the literature to solve the route optimization problem in mobile networks. The route optimization solutions generate overheads and affect the performance of mobile networks. However, currently there is no tool available to aid in the selection of an appropriate scheme for a given mobility scenario. The objective of this paper is to develop analytical models for prefix delegation based schemes and compare the performance of the schemes for different mobility scenarios. Results show that the performance of a scheme depends on the characteristics of the mobile network, and there is no single scheme which suits all mobility scenarios.