MPLS Research Articles

Optical Networks Control and Management

Control and management play a key role in enabling optical networks to efficiently and smoothly carry user data. In the recent years, there has been much advance in the areas, ranging from the traditional Generalized Multi-Protocol Label Switching (GMPLS) to today’s Path Computation Element (PCE)-based technology. In addition, elastic, spectrum-efficient and gridless optical networks, reduction of energy consumption, and Software Defined Networking (SDN) in optical networks are gaining attention from both research community and network operators. Consequently, network control and management system that can efficiently allocate optical fiber spectrum resources and support energy-efficient operation will be another exciting near-term research focus. The future optical network management and control plane is expected to be more versatile, scalable, automatic, and resource-efficient.

The study of multi-granularity switching based on parallel processing routing technology

A novel parallel processing optical code label-switched paths (PP-OC-LSPs) is proposed to achieve efficient conversion performance for core router and large throughput in optical network, which combines the merits of optical label switching (OLS), optical code-generalized multi-protocol label switching (OC-GMPLS), and optical code division multiplexing-paths (OCDM-paths) technology. In the proposed technology, the smallest switching granularity is an optical code which carries the label information of data packets and would be parallel converted in the core router. In the edge node, the label and payload are separated by using the optical polarity characteristics, and encoded/decoded with two different code series based on OCDM techniques so as to process them in parallel. Compared with the OLS, its switching capability has been extended to support fiber switching, wavelength switching, and OCDM switching. We present simulation results to demonstrate its performance over OCDM-paths technology.

Label switched protocol routing with guaranteed bandwidth and end to end path delay in MPLS networks

Rapid growth of multimedia applications has caused a tremendous impact on how people communicate. Next generation networks (NGN) have been proposed to support newly emerged multimedia IP based applications such as voice over IP (VOIP), video on-demand (VOD), and IPTV using a core IP backbone. The development of technologies like Multi-Protocol Label Switching (MPLS) has laid the foundation for NGN to support multimedia applications like Voice over IP. One of the important concepts in MPLS Traffic Engineering (TE) is Label Switched Path (LSP) routing. The objective of the routing algorithm is to increase the number of accepted request while satisfying Quality of Service (QoS) constraints. Although much work has been done on laying MPLS paths to optimize performance, most of them have focused on satisfying bandwidth requirements. Relatively little research has been done on laying paths with both bandwidth and delay constraints. In this paper, we present a new bandwidth and end to end delay (bandwidth-delay) constrained routing algorithm which uses data of the ingress–egress node pairs in the network. In this algorithm we use LR-Servers theory to compute path delay. We name the proposed algorithm as Minimum Delay and Maximum Flow (MDMF). We do extensive simulations to evaluate the performance of MDMF algorithm. In addition, we compare the performance of MDMF against some previous related works such as MHA, WSP, MIRA, BCRA, MIRAD, BGDG, BGLC, and SAMCRA. The simulation results show that MDMF rivals them in terms of flow management and outperform them in terms of end to end delay management, maximum flow and number of accepted request (call blocking ratio).

Improvement of Quality of Service (QoS) over a Wide Area Network (WAN) using Multiprotocol Label Switching Traffic Engineering (MPLS-TE)

refers to the amount of data that can be transmitted in a specific time over a wireless or wired medium. It is an important factor that is used to analyze network performance, design new networks, and understand the internet. Multi- protocol label switching (MPLS) originated from tag switching and enables the consolidation of applications onto a single network whilst providing the mechanism to prioritize the latency of individual applications within application classes. It is a more efficient way to transfer data between wide area networks and thus helps to reduce cost and increase bandwidth, throughput and reliability. In this paper we demonstrated by simulation experiment that MPLS-TE can help decongest routing path thereby ensuring improved network performance by reducing the traffic on a network segment, and increasing network throughput and reliability. KeywordsLatency, Local Area Network, MPLS/TE, Throughput

Highly Reliable and Large-Capacity Packet Transport Networks: Technologies, Perspectives, and Standardization

With the recent prevalence of Internet protocol-based services, packet traffic is rapidly becoming the mainstream of data traffic. This has increased the demand for transport network technology that can efficiently accommodate the large capacity of both packet-based and circuit-based traffic while achieving high reliability, sufficient operation, and maintenance capability comparable to that of traditional transport networks such as synchronous digital hierarchy or optical transport networks. This study gives an overview of packet transport technologies including Ethernet and multiprotocol label switching (MPLS), and provides details of MPLS-TP (transport profile), recently developed as a promising next-generation packet transport technology. Its standardization in International Telecommunication Union, Telecommunication Standardization Sector and Internet Engineering Task Force is also described. Then, further perspectives are given on MPLS-TP applications including layer convergence of transport networks for cost-effective and simple operation.

Stochastic hierarchical multiobjective routing model in MPLS networks with two service classes: an experimental study on imprecision and uncertainty issues

The paper begins by reviewing a two-level hierarchical multicriteria routing model for Multiprotocol Label Switching networks with two service classes (Quality of Service and Best Effort services) and alternative routing, previously proposed by the authors. The features of the considered resolution heuristic are described. Some key issues raised by its complexity are discussed, as well as the major factors that constitute the sources of imprecision, inaccuracy, and uncertainty of the model and the way in which they are dealt with in the adopted resolution approach. Analytic and stochastic discrete-event simulation experiments are performed for different test networks, including experiments with a dynamic version of the routing method. This case study allows for the evaluation of the inaccuracies intrinsic to the analytic/numerical resolution procedures and of the uncertainty associated with the estimates of the mean of the stochastic traffic flows. An analysis focused on key robustness aspects of the model is also carried out.AMS Subject ClassificationPrimary 90B50; secondary 90B18; 90B15

Using GENI for experimental evaluation of Software Defined Networking in smart grids

The North American Electric Reliability Corporation (NERC) envisions a smart grid that aggressively explores advance communication network solutions to facilitate real-time monitoring and dynamic control of the bulk electric power system. At the distribution level, the smart grid integrates renewable generation and energy storage mechanisms to improve the reliability of the grid. Furthermore, dynamic pricing and demand management provide customers an avenue to interact with the power system to determine the electricity usage that best satisfies their lifestyle. At the transmission level, efficient communication and a highly automated architecture provide visibility in the power system and as a result, faults are mitigated faster than they can propagate. However, such higher levels of reliability and efficiency rest on the supporting communication infrastructure. To date, utility companies are moving towards Multiprotocol Label Switching (MPLS) because it supports traffic engineering and virtual private networks (VPNs). Furthermore, it provides Quality of Service (QoS) guarantees and fail-over mechanisms in addition to meeting the requirement of non-routability as stipulated by NERC. However, these benefits come at a cost for the infrastructure that supports the full MPLS specification. With this realization and given a two week implementation and deployment window in GENI, we explore the modularity and flexibility provided by the low cost OpenFlow Software Defined Networking (SDN) solution. In particular, we use OpenFlow to provide (1) automatic fail-over mechanisms, (2) a load balancing, and (3) Quality of Service guarantees: all essential mechanisms for smart grid networks.

Load balancing Technique for VOIP in MPLS Networks

In recent years, there has been a phenomenal growth in the commercial deployment of delay-sensitive services, such as voice and video services, over the Internet Protocol. Regardless of the advances that have been witnessed in networking technologies, effectively utilizing the network resources to accommodate such services remains a major and challenging task for network researchers and designers. In MPLS networks, multiple label switched paths are (LSP) are established between MPLS ingress and egress nodes to enhance the network performance and QoS for subscribers. During unbalanced situation in the network, the flows are routed through multiple paths. Keywords- MPLS, load balancing, , VoIP and QoS, broadband scenario, Voice, multipath dispersion, , IP network.

Class-Based Constraint-Based Routing with Implemented Fuzzy Logic in MPLS-TE Networks

The paper deals with constraint-based routing (CBR) in MPLS-TE networks and proposes a new CBR algorithm based on fuzzy logic called Fuzzy Class-Based Algorithm (FCBA). Multiprotocol label switching with traffic engineering (MPLS-TE) networks represent a popular mechanism to effectively use resources of service providers’ core networks. The paths can be either built by administrators (explicit routing) or built by using existing routing algorithms which mostly decide based on the shortest paths towards the destination which might not be sufficient in nowadays’ multimedia networks. To address this problem various CBR algorithms have emerged which take into consideration various aspects important to existing traffic like QoS parameters or administrative policies. FCBA makes routing decisions based on traffic classes and by using fuzzy logic we can assign normalized values to various constraints based on the traffic class’ preferences (e.g., low delay paths for voice traffic) and network administrator’s preferences (e.g., avoiding congested links). The paper provides comparison of FCBA with existing CBR approaches based on their ability to provide QoS parameters loss. The simulations show that FCBA provides the best results for the highest priority traffic where it uses lower priority traffic to efficiently utilize the network.

ESTIMACIÓN Y OPTIMIZACIÓN DEL BALANCEO DE CARGA USANDO INGENIERÍA DE TRÁFICO ADAPTATIVA MATE EN REDES DE CONMUTACIÓN DE ETIQUETAS MULTIPROTOCOLO GENERALIZADO (GMPLS)

The article proposes the use of load balancing algorithm with (MATE) adaptive traffic engineering to be used as load distributor through multiple links on Generalized Multiprotocol Label Switching networks (GMPLS). This with the purpose of making more efficient distribution of the existing routes between the origin and destination of the data. The methodology included the algorithm, implemented in C++ to assess their performance in the discrete event simulator NS-2 and from the results generating an optimization proposal that would raise their performance. In can be noted that MATE presents stability problems that were solved by the modeling of adaptive convergence function valid for GMPLS networks.

Multi-constrained path computation for inter-domain QoS-capable services

Computing inter-domain multiprotocol label switching traffic engineering label switched path MPLS-TE LSP through a pre-determined sequence of domains is quite straight as each path computation element PCE, using the backward recursive PCE-based computation BRPC, knows who is the next to be contacted in order to continue the computation. The optimality of the inter-domain MPLS-TE LSP path depends strongly on the choice of the pre-determined sequence of domains on which the calculation works. In this paper, we propose a novel procedure allowing a forward discovery of multiple inter-domain sequences and the computation of constrained inter-domain paths for MPLS-TE LSPs over these domains sequences. Other issues around the inter-domain path computation, such as route discovery and inter-domain loop avoidance, are investigated. Experimental evaluation shows that our solution is effective in terms of protocol and algorithmic efficiency and provides satisfiable performance with high success rate, reasonable message overhead and runtime.

EVALUACIÓN DE PROTOCOLOS DE SEÑALIZACIÓN EN MULTIPROTOCOLO GENERALIZADO DE CONMUTACIÓN DE ETIQUETAS (GMPLS) CAPACES DE CONMUTAR PAQUETES Y LONGITUDES DE ONDAS

In this paper, RSVP-TE and CR-LDP signaling protocols in the Generalized Multiprotocol Label Switching (GMPLS) are evaluated based on the design parameters of the physical layer, and packets and wavelength switching. In the simulations, of the signaling protocols the results do not present important discrepancies. The use of the UDP segmentation in RSVP-TE and of TCP in CR-LDP, present differences in the so-called LSP state. Additionally, some characteristics of each of the objects in RSVP that add other functionalities to each protocol. The results show the delay, throughput and jitter, for each signaling protocol, using the GLASS simulation tool.

Multicast in Multi Protocol Label Switching: A comparison study between LDP and RSVP-TE

Resource ReSerVation Protocol-Traffic Engineering (RSVP-TE), andLabel Distribution Protocol (LDP) may be used to set up Point toMulti Point (P2MP) trees in MPLS. RSVP-TE performs better inoptimizing network resources, while LDP is simpler but has noguarantee on resource optimization. This paper presents acomparative study between RSVP-TE and LDP in regards of resourceoptimization and the resulting impact on the amount of memoryconsumed. It shows that the amount of memory needed in the case ofRSVP-TE grows linearly as the size of the tree increases. Incontrast, an approximate constant behavior is observed in the caseof LDP, yielding an important scalability property. The paper thenproposes two extensions to LDP aiming to achieve better resourceoptimization. In both extensions, a new leaf is provided a partialtree knowledge, by involving either all the nodes of the tree oronly its leaves. The leaf joins the tree by connecting to theclosest node among the known ones. Valuable comparisons withRSVP-TE are performed, and they represent an important backgroundto decide when and how to use each protocol.

Protocol enhancements for “greening” optical networks

The last decade has spurred a number of research efforts around energy efficiency in information and communication technologies (ICT). To reduce the energy consumed by optical transport networks, one option is to switch-off a certain number of optical systems according to the amount of transported traffic. Consequently, dynamic power management of optoelectronic devices and link sleep-mode approaches have been proposed; these capabilities quantitatively optimize the power requirements and the available bandwidth of the network as a whole. This paper presents enhancements embedded in Generalized Multiprotocol Label Switching (GMPLS)-based protocols enabling power control in optical devices, and then analyzes the impact of controlling the daily energy consumption of optical switching equipment in the network. We also present ongoing activities in specific standardization working groups for “greening the network” along with their proposals to improve the energy efficiency of future optical networks.

Virtual Optical Network Resource Allocation Using PCE Global Concurrent Optimization for Dynamic Deployment of Virtual GMPLS-Controlled WSON

We present dynamic virtual optical network resource allocation (VON RA) algorithms for on-demand deployment of virtual wavelength switched optical networks (WSONs), which is handled by a resource broker with a virtual network topology manager (VNTM). The resource broker with VNTM dynamically configures and deploys independent instances of virtual WSONs over the same physical optical infrastructure and their own independent virtual generalized multiprotocol label switching control plane. The VON RA is computed by a path computation element using global concurrent optimization, which assigns the resources for the virtual optical links (e.g., wavelengths) and nodes. The experimental assessment and performance evaluation have been carried out in the ADRENALINE testbed. We discuss the obtained results on a National Science Foundation Network topology in terms of the VON request blocking rate and VON setup delay, which are used to compare the different proposed algorithms.

MPLS technology in wireless networks

Recently, there has been increasing demand for Multi-protocol label switching (MPLS) technology in most internet service provider networks. The application of MPLS technology in wireless networking...

Scheduling Algorithms for Primary LSPs with n-to-m Protection in MPLS Networks

The protection mechanism is very important in networks when working paths fall failure. In this paper, we propose a scheduling mechanism with n-to-m protection (n is the number of primary LSPs (Label Switching Path), m is the number of backup LSPs) in MPLS (Multi-Protocol Label Switching) networks. Two scheduling algorithms are proposed: the flrst algorithm is MMMSA (maximize mixing metric scheduling algorithm), aiming at maximize the mixing metrics of backup LSPs by calculating the proportion of each ∞ow that transferred from primary LSPs to backup LSPs with linear programming; the second algorithm is AHP-WSA (analytic hierarchy process-weight scheduling algorithm), considering multi-metrics (bandwidth, delay, package error rate) of backup LSPs separately and making pairwise comparison of the alternatives, then flnding out each backup LSP’s weight to a speciflc primary LSP and scheduling the ∞ows with theses weights. Simulation results show that these algorithms can achieve e‐cient and high performance scheduling.

IP Backbone Security: MPLS VPN Technology

The Multiprotocol Label Switching (MPLS) technology is currently the most deployed technology by service providers over backbone networks. The highly useful MPLS application nowadays is the MPLS Virtual Private Network (VPN). Due to the enterprises and organizations demand of allowing the remote sites and users to connect to enterprise network, MPLS VPNs have become more attractive. The service providers are using MPLS VPN technology to provide the end users a secure channel across the public internet, with flexibility and scalability. MPLS VPNs have the functionality to operate over both MPLS networks as well as existing IP networks. Variety of research has been conducted in this area and many researchers have proposed different models and solutions to implement MPLS VPN technology more effectively and efficiently. This paper presents the detail analysis of the existing and future techniques and models which are used to implement, optimize, secure MPLS VPN technology.

The Role of Code-switching as a Communicative Tool in an ESL Teacher Education Classroom

Abstract This research sought to investigate how code-switching functions as a communicative tool in a English as a second language teacher education class in a tertiary institution in Malaysia. Surveys, observations, and interviews were carried out to elicit relevant data. Qualitative data was collected using an observational framework. The findings revealed that three types of code-switching known as tag switching, inter-sentential switching, and intra-sentential switching were predominant in classroom communication between students and between students and the instructor. The study was also able to ratify several systematic and predictive reasons for code-switching in the classroom. The study also found that English was the dominant language of communication while code switching was used to convey ideas in specific situations and to enhance solidarity in the first language.

Mobility management in packet transport networks for network convergence

AbstractMobility management and quality of service (QoS) are two of the most important goals in the present and future development of wireless networks. These tasks involve not only the wireless domain but also the access network that interconnects mobile devices with the Internet. This emerging topic is known as fixed mobile convergence. The intention of this convergence is the integration and creation of a unified infrastructure from fixed and wireless mobile networks. In this converged infrastructure, users can move across networks and access services seamlessly. In this paper, we present a study on recent advances and open research issues on mobility protocols in conjunction with multi‐protocol label switching (MPLS)‐based access networks. Various mobile management protocols and their interaction with the access network are briefly introduced. A new architecture called integrated proxy mobile MPLS transport profile is also outlined to provide the highest integration level, QoS and high rates of mobility to achieve fixed mobile convergence. Copyright © 2013 John Wiley & Sons, Ltd.