Route Optimization Procedure Research Articles

A column generation based heuristic for the generalized vehicle routing problem with time windows

The generalized vehicle routing problem with time windows (GVRPTW) is defined on a directed graph G=(V,A) where the vertex set V is partitioned into clusters. One cluster contains only the depot, where is located a homogeneous fleet of vehicles, each with a limited capacity. The other clusters represent customers. A demand is associated with each cluster. Inside a cluster, the vertices represent the possible locations of the customer. A time window is associated with each vertex, during which the visit must take place if the vertex is visited. The objective is to find a set of routes such that the total traveling cost is minimized, exactly one vertex per cluster is visited, and all the capacity and time constraints are respected. This paper presents a set covering formulation for the GVRPTW which is used to provide a column generation based heuristic to solve it. The proposed solving method combines several components including a construction heuristic, a route optimization procedure, local search operators and the generation of negative reduced cost routes. Experimental results on benchmark instances show that the proposed algorithm is efficient and high-quality solutions for instances with up to 120 clusters are obtained within short computation times.

FPKIN: Firewall Public Key Infrastructure for NEMO

Network mobility (NEMO) is an important requirement for internet networks to reach the goal of ubiquitous connectivity. With NEMO basic support protocols, correspondent entities suffer from a number of limitations and problems that prevent route-optimization procedures to be established between the correspondent nodes and mobile network nodes associated with NEMO. The goal is to alleviate the signaling load and execute the route-optimization steps on behalf of the correspondent entities that are not sophisticated enough to support route optimization. This paper introduces a new architecture that uses firewall as a new entity with new mobility filtering rules and acts as root certificate server supporting PKI infrastructure. The PKI-firewall executes the route-optimization procedure on behalf of these correspondent entities depends on CA distributed to its mobile end nodes. User entities is reachable via optimized path approved by mobile node or user CA As a result of completing the above procedure, performance degradation will be reduced, especially when signaling storm occurs; applying these modifications will increase the security, availability and scalability of NEMO optimization and enable wider NEMO deployment. An analytical model is used to validate the new proposed framework and understand the behavior of this framework under different network scenarios.

A Route Optimized Distributed IP-Based Mobility Management Protocol for Seamless Handoff across Wireless Mesh Networks

A Wireless Mesh Network (WMN) can provide Internet connectivity to end users through heterogenous access network technologies. However, the mobility of mobile nodes across these access networks in WMNs results in service disruption. Existing mobility management protocols are designed for single hop networks and are centralized in nature. A Distributed IP-based Mobility Management Protocol (DIMMP) is proposed in this paper that provides seamless mobility with service continuation for mobile nodes when they roam across WMNs. Instead of relying on a centralized mobility anchor, the mobility functionality is distributed at multiple nodes in the WMN, in order to reduce the chances of potential single point of failure. The proposed protocol manages both types of mobilities i.e. intra-WMN and inter-WMN and uses a new enhanced route optimization procedure. Simulation results show that this work has contributed by improving the performance of handoff procedure with respect to handoff latency, packet loss and signalling overhead, as compared to the existing protocols.

Reducing field work time using fleet routing optimization

Agricultural producers seek to complete their field work operations as quickly as possible. This is achievable through the simultaneous use of multiple vehicles for an operation. However, path allocation and scheduling then must be considered. Transforming the field work problem into a Vehicle Routing Problem (VRP) and using optimization procedures designed for this problem provides a method of allocating paths. In this work, the accuracy of a VRP representation of field work is confirmed and the ability of this optimization system to reduce field work times is verified. Experiments were conducted using three tractors during a rotary mowing operation. First, the traditional routes used by human drivers were recorded. Then, a VRP representation of this operation was created, and new routes generated by a Tabu Search optimization procedure. Finally, the field operation was repeated using the optimized routes. Using these routes, the time to complete the field work was reduced by 17.3% and the total operating time for all tractors was reduced by 11.5%. The predictions by the VRP representation for completion time and total time were both within 2% of the actual times recorded when the tractors followed the computer-generated routes in the field. These reductions illustrated the ability of the route optimization procedure to improve effective field efficiency.

Improving Mobile IP Performance Through Priority Scheduling

The increasing number of portable computers, combined with the growth of wireless services, makes supporting Internet mobility important. Since a mobile node always changes its point of attachment to the Internet, it may cross a cell boundary during data transmission process. Packets sequence disruption during handover procedure may result in decreasing network performance especially in higher layers protocols. In this paper we investigate the behavior of Mobile IP protocol in presence of route optimization procedure. We discuss the impact of handover process on packets routed from old Foreign Agent to new Foreign Agent after handover and show that using priority scheduling for packets received from the Home Agent and queued at the old Foreign Agent's buffer after handover can reduce the number of disordered packets received at the new Foreign Agent after handover.

Optimal routing for efficient municipal solid waste transportation by using ArcGIS application in Chennai, India.

Worldwide, about US$410 billion is spent every year to manage four billion tonnes of municipal solid wastes (MSW). Transport cost alone constitutes more than 50% of the total expenditure on solid waste management (SWM) in major cities of the developed world and the collection and transport cost is about 85% in the developing world. There is a need to improve the ability of the city administrators to manage the municipal solid wastes with least cost. Since 2000, new technologies such as geographical information system (GIS) and related optimization software have been used to optimize the haul route distances. The city limits of Chennai were extended from 175 to 426 km(2) in 2011, leading to sub-optimum levels in solid waste transportation of 4840 tonnes per day. After developing a spatial database for the whole of Chennai with 200 wards, the route optimization procedures have been run for the transport of solid wastes from 13 wards (generating nodes) to one transfer station (intermediary before landfill), using ArcGIS. The optimization process reduced the distances travelled by 9.93%. The annual total cost incurred for this segment alone is Indian Rupees (INR) 226.1 million. Savings in terms of time taken for both the current and shortest paths have also been computed, considering traffic conditions. The overall savings are thus very meaningful and call for optimization of the haul routes for the entire Chennai.

A DNS-assisted Simultaneous Mobility Support Procedure for Mobile IPv6

Mobile IPv6 was proposed to provide mobility support to IPv6 based mobile devices. It includes a route optimization procedure, to overcome the problem of triangular routing, which allows the correspondent node to send packets directly to the mobile node's care-of address. However, when both communicating devices are mobile, Mobile IPv6's route optimization can not handle the handover thus service disruption occurs and communication is stopped. This paper presents a new DNS-assisted solution for Mobile IPv6 to overcome the problem of simultaneous mobility. The proposed mechanism makes some necessary changes in the Mobile IPv6's route optimization procedure and executes handover differently in different scenarios depending upon the type of mobility of communicating nodes in overlapped or non-overlapped coverage access networks. Simulation results show that when proposed mechanism was used for simultaneous mobility, it successfully resumed the communication as compared to Mobile IPv6 where communication was stopped.

A TOTP-Based Enhanced Route Optimization Procedure for Mobile IPv6 to Reduce Handover Delay and Signalling Overhead

Due to the proliferation of handheld mobile devices, multimedia applications like Voice over IP (VoIP), video conferencing, network music, and online gaming are gaining popularity in recent years. These applications are well known to be delay sensitive and resource demanding. The mobility of mobile devices, running these applications, across different networks causes delay and service disruption. Mobile IPv6 was proposed to provide mobility support to IPv6-based mobile nodes for continuous communication when they roam across different networks. However, the Route Optimization procedure in Mobile IPv6 involves the verification of mobile node's reachability at the home address and at the care-of address (home test and care-of test) that results in higher handover delays and signalling overhead. This paper presents an enhanced procedure, time-based one-time password Route Optimization (TOTP-RO), for Mobile IPv6 Route Optimization that uses the concepts of shared secret Token, time based one-time password (TOTP) along with verification of the mobile node via direct communication and maintaining the status of correspondent node's compatibility. The TOTP-RO was implemented in network simulator (NS-2) and an analytical analysis was also made. Analysis showed that TOTP-RO has lower handover delays, packet loss, and signalling overhead with an increased level of security as compared to the standard Mobile IPv6's Return-Routability-based Route Optimization (RR-RO).

A solution for transparent mobility with route optimization in the IP multimedia subsystem

This paper presents TRIM+, an architecture for transparent mobility management with route optimization in IMS based networks. The design of our architecture is based on a previous work referred to as TRIM. TRIM was originally devised to provide transparent mobility support in the IMS, although transparency came at the cost of using a suboptimal data path between communicating end points. TRIM+ maintains transparency as a design criterium, and thus end-user applications, running at the mobile node and its correspondent communication peers, are unaware of mobility management procedures. Additionally, the proposed design defines a set of route optimization procedures, allowing compliant devices to use the optimal data path for media communications. Furthermore, TRIM+ addresses packet loss management in scenarios where the media path cannot be maintained during the handover of the MN. To this end, our architecture enables the MN to request buffering capacity in its home network to temporarily store incoming media traffic during the handover, which would otherwise be dropped. This mechanism, as well as route optimization procedures, are executed transparently to the end-user applications running at the communicating end points. As a proof-of-concept, we have implemented a software prototype of the TRIM+ architecture, deploying it over a real IMS testbed. By means of a set of experiments, we have validated the mechanisms proposed in this paper, considering both UDP and TCP user traffic.

A Secure Correspondent Router Protocol for NEMO Route Optimization

The Network Mobility (NEMO) protocol is needed to support the world-wide mobility of aircraft mobile networks across different access networks in the future IPv6 based aeronautical telecommunications network (ATN). NEMO suffers from the constraint that all traffic has to be routed via the home agent though. The already existing correspondent router (CR) protocol solves this triangular routing problem and permits to route packets on a direct path between the mobile network and the ground based correspondent nodes. We identify security deficiencies of this protocol that make it unsuitable for use within the ATN. We therefore propose a new route optimization procedure based on the CR protocol that provides a higher level of security. We evaluate our new protocol in three ways. We first conduct a simulation based handover performance study using an implementation of a realistic aeronautical access technology. We then investigate the mobility signaling overhead. Finally, we specify a threat model applicable for the aeronautical environment and use it to perform a security analysis of both the old and our new protocol. It is shown that our protocol is not only more secure but also provides better handover latency, smaller overhead in the aeronautical scenario and a higher level of resilience when compared to the original CR protocol.

A Network-Based Localized Mobility Approach for Locator/ID Separation Protocol

Locator/ID Separation Protocol (LISP) is an efficient proposal for solving the severe routing scalability problems existing in the current IPv4-based Internet and the future IPv6-based Internet. However, the basic LISP architecture does not specify how to support mobility in detail. As mobility is a fundamental issue faced by the future Internet, LISP mobility architecture (LISP-MN) was proposed recently to extend LISP to support mobility. Nevertheless, LISP-MN is a host-based mobility approach which requires software changes in end systems. To some extent, such a design breaks the primary design principles of LISP, which is a network-based protocol and requires no modification to the hosts. In addition, LISP-MN faces the same inherent problems as other host-based approaches (e.g., MIPv4, MIPv6), such as handover latency, packet loss, and signalling overhead. To solve the above problems, this paper proposes MobileID, which is a network-based localized mobility approach for LISP. In our design, a mobile node is not aware of its mobility and does not participate in handover signalling. Instead, the network takes the responsibility for managing mobility on behalf of the mobile node. We present a general overview of MobileID architecture, and introduce the detailed protocol operations in terms of the basic MobileID handover process and the route optimization procedures. Furthermore, we describe a MobileID analytic model, and compare MobileID handover performance with three representative mobility solutions, i.e., LISP-MN, MIPv6 and PMIPv6. Numerical results show the superior performance of MobileID. The handover latency of MobileID is much lower than those of LISP-MN and MIPv6, and it becomes lower than that of PMIPv6 in case of a long wireless link delay.

Improving Mobile IP Performance Through Priority Scheduling

The increasing number of portable computers, combined with the growth of wireless services, makes supporting Internet mobility important. Since a mobile node always changes its point of attachment to the Internet, it may cross a cell boundary during data transmission process. Packets sequence disruption during handover procedure may result in decreasing network performance especially in higher layers protocols. In this paper we investigate the behavior of Mobile IP protocol in presence of route optimization procedure. We discuss the impact of handover process on packets routed from old Foreign Agent to new Foreign Agent after handover and show that using priority scheduling for packets received from the Home Agent and queued at the old Foreign Agent's buffer after handover can reduce the number of disordered packets received at the new Foreign Agent after handover.

PMIPv6에서 사전 인증 기법과 경로 최적화를 이용한 효율적인 핸드오버 기법에 관한 연구

PMIPv6는 IETF의 NetLMM WG에서 표준화를 진행하는 네트워크 기반 이동성 지원 기법으로서, 기존의 단말 기반 이동성 지원 기법의 문제점과 비효율성을 개선하기 위해 제안되었다. IETF에서 공개한 표준 문서는 MN에게 이동성을 제공하기 위한 네트워크 구성 요소와 그 구체적인 동작 및 핸드오버 절차에 대해 서술하고 있다. 그러나 MAG간 핸드오버에 대해서만 정의되어 있고 LMA간 핸드오버에 대해서는 정의되어 있지 않다. 따라서 MN에게 보다 효율적으로 끊김 없는 인터넷 접속을 제공하기 위해서는 LMA간 핸드오버 기법이 함께 사용되어야 한다. 본 논문에서 제안하는 기법은 기존에 제안된 LMA간 핸드오버 기법의 단점인 LMA간 터널을 사용하지 않고, 경로 최적화 절차를 거쳐 효율적인 전송 경로를 사용한다. 또한 핸드오버 지연을 줄이기 위해 사전 인증 기법을 도입하였다. 성능 분석 결과에 따르면 제안하는 기법이 기존의 이동성 지원 기법에 비해 핸드오버 지연을 크게 감소시키는 것을 확인할 수 있었다. PMIPv6 is a network-based mobility support scheme, proposed and standardized by NetLMM WG of IETF. It is proposed to solve problems of conventional mobility schemes, and to improve inefficiency of those. The standard document describes network components and detailed procedures to provide mobility to MN. But it describes only a handover procedure between MAGs, not between LMAs. In order to support seamless connectivity of MN efficiently, a handover procedure between LMAs is necessary. The proposed scheme in this paper utilizes a route optimization procedure to prevent inefficiency of inter-LMA tunneling scheme. At the same time, the proposed scheme utilizes a pre-authentication scheme to reduce handover latency. According to the result of performance evaluations, the proposed scheme greatly reduces handover latency, compared to conventional mobility support schemes.

LMA initiated route optimization protocol for improving PMIP handover performance

We propose a Local Mobility Anchor (LMA) initiated route optimization protocol for a smooth transition from the old optimized path to a new optimized path after handover in Proxy Mobile IP (PMIP). The LMA initiated protocol can reduce the handover latency and achieve fast recovery of the optimized path after handover. As a result, the proposed protocol solves the out-of-sequence delivery problem during the route optimization procedure.

On using Mobile IP Protocols

The recent advances in wireless communication technology and the unprecedented growth of the Internet have paved the way for wireless networking and IP mobility. Mobile Internet protocol has been designed within the IETF to support the mobility of users who wish to connect to the Internet and maintain communications as they move from place to place. This study describes and summarizes the current Internet draft for mobile IP (MIPv4) with its major components: agent discovery, registration and tunneling. In addition, we outline the available encapsulation techniques and route optimization procedure. In the end, we describe the design of the new protocol for transparent routing of IPv6 packets to mobile IPv6 nodes operating in the Internet.

Mobile IP

Mobile IP has been designed within the Internet Engineering Task Force (IETF) to serve the needs of the burgeoning population of mobile computer users who wish to connect to the Internet and maintain communications as they move from place to place. The basic protocol is described, with details given on the three major component protocols: agent advertisement, registration, and tunneling. Then route optimization procedures are outlined, and further topics of current interest are described. The available tunneling mechanisms are shown, which the home agent uses to forward datagrams from the home network to the mobile computer. Having covered the details of the base mobile IP specification, we then describe further protocol messages which help to decrease the inefficiency associated with inserting the home agent in the routing path of data destined for mobile computers. Finally, we summarize and discuss the current problems facing mobile IP, as well as a few areas of active protocol development.

Mobile location management in ATM networks

This paper presents two mobile location management algorithms for ATM (asynchronous transfer mode) networks based on the PNNI (private network-to-network interface) standard. The first solution is called the mobile PNNI scheme because it builds on the PNNI routing protocol. It uses limited-scope (characterized by a parameter S) reachability updates, forwarding pointers, and a route optimization procedure. The second solution is called the LR (location registers) scheme because it introduces location registers (such as the cellular home and visitor location registers) into the PNNI standards-based hierarchical networks. This scheme uses a hierarchical arrangement of location registers with the hierarchy limited to a certain level S. Analytical models are set up to compare the average move, search, and total costs per move of these two schemes for different values of the CMR (call-to-mobility ratio), and to provide guidelines for selecting parameters of the algorithms. Results show that at low CMRs (CMR<0.025), the LR scheme performs better than the mobile PNNI scheme. We also observe that the two schemes show a contrasting behavior in terms of the value to be used for the parameter S to achieve the least average total cost. At low CMRs, the parameter S should be high for the mobile PNNI scheme, but low for the LR scheme, and vice versa for high CMRs.

An Overview of Current Methods Used in Weather Routeing

The aim of this paper is to provide a collective overview of current state-of-the-art weather routeing and it is therefore intended to give a descriptive appraisal. Essentially the paper will concentrate upon the vessel route optimization procedures, data-handling techniques including the parameters necessary to implement the methods, the ship-resistance characteristics and the James speed performance curves.