Multi-Layer Design of IP over WDM Backbone Networks: Impact on Cost and Survivability

To address the reliability challenges due to failures and planned outages, Internet Service Providers (ISPs) typically use two backbone routers at each central office to which access routers connected in a dual-homed configuration. At the IP layer, redundant backbone routers and redundant transport equipment to interconnect them are deployed, providing reliability through node and path diversity. However, adding such redundant resources increases the overall cost of the network. Hence, a fundamental redesign of the backbone network avoiding such redundant resources, by leveraging the capabilities of an agile optical transport network, is highly desired. In this paper, we propose such a fundamental redesign of IP backbones. Our alternative design uses only a single router at each office but uses the agile optical transport layer to carry traffic to remote Backbone Routers (BRs) in order to survive failures or outages of the single local BR. Optimal mapping of local Access Routers (ARs) to remote BRs is determined by solving an Integer Linear Program (ILP). We describe how our proposed design can be realized using current optical transport technology. We evaluate network designs for cost and performability, the latter being a metric combining performance and availability. We show significant reduction in cost for approximately the same level of reliability as current designs

Design of multi-homing architecture for mobile hosts

This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.This thesis proposes a new multi-homing mobile architecture for future heterogeneous network environment. First, a new multi-homed mobile architecture called Multi Network Switching enabled Mobile IPv6 (MNS-MIP6) is proposed which enables a Mobile Node (MN) having multiple communication paths between itself and its Correspondent Node (CN) to take full advantage of being multi-homed. Multiple communication paths exist because MN, CN, or both are simultaneously attached to multiple access networks. A new sub layer is introduced within IP layer of the host’s protocol stack. A context is established between the MN and the CN. Through this context, additional IP addresses are exchanged between the two. Our MNS-MIP6 architecture allows one communication to smoothly switch from one interface/communication path to another. This switch remains transparent to other layers above IP. Second, to make communication more reliable in multi-homed mobile environments, a new failure detection and recovery mechanism called Mobile Reach ability Protocol (M-REAP) is designed within the proposed MNS-MIP6 architecture. The analysis shows that our new mechanism makes communication more reliable than the existing failure detection and recovery procedures in multi-homed mobile environments. Third, a new network selection mechanism is introduced in the proposed architecture which enables a multi-homed MN to choose the network best suited for particular application traffic. A Policy Engine is defined which takes parameters from iv the available networks, compares them according to application profiles and user preferences, and chooses the best network. The results show that in multi-homed mobile environment, load can be shared among different networks/interfaces through our proposed load sharing mechanism. Fourth, a seamless handover procedure is introduced in the system which enables multi-homed MN to seamlessly roam in a heterogeneous network environment. Layer 2 triggers are defined which assist in handover process. When Signal to Noise Ratio (SNR) on a currently used active interface becomes low, a switch is made to a different active interface. We show through mathematical and simulation analysis that our proposed scheme outperforms the existing popular handover management enhancement scheme in MIPv6 networks namely Fast Handover for MIPv6 (FMIPv6). Finally, a mechanism is introduced to allow legacy hosts to communicate with MNS-MIP6 MNs and gain the benefits of reliability, load sharing and seamless handover. The mechanism involves introducing middle boxes in CN’s network. These boxes are called Proxy-MNS boxes. Context is established between the middle boxes and a multi-homed MN

Hierarchical Ring Network Design Using Branch-and-Price

Abstract. We consider the problem of designing hierarchical two layer ring networks. The top layer consists of a federal-ring which establishes connection between a number of node disjoint metro-rings in a bottom layer. The objective is to minimize the costs of links in the network, taking both the fixed link establishment costs and the link capacity costs into account. Hierarchical ring network design problems combines the following optimization problems: Clustering, hub selection, metro ring design, federal ring design and routing problems. In this paper a branch-and-price algorithm is presented for jointly solving the clustering problem, the metro ring design problem and the routing problem. Computational results are given for networks with up to 36 nodes

Fiber optical network design problems : case for Turkey

Ankara : The Department of Industrial Engineering and the Graduate School of Engineering and Science of Bilkent University, 2013.Thesis (Master's) -- Bilkent University, 2013.Includes bibliographical references leaves 102-110.The problems within scope of this thesis are based on an application arising from one of the largest Internet service providers operating in Turkey. There are mainly two different problems: the green field design and copper field re-design. In the green field design problem, the aim is to design a least cost fiber optical network from scratch that will provide high bandwidth Internet access from a given central station to a set of aggregated demand nodes. Such an access can be provided either directly by installing fibers or indirectly by utilizing passive splitters. Insertion loss, bandwidth level and distance limitations should simultaneously be considered in order to provide a least cost design to enable the required service level. On the other hand, in the re-design of the copper field application, the aim is to improve the current service level by augmenting the network through fiber optical wires. Copper rings in the existing infrastructure are augmented with cabinets and direct fiber links from cabinets to demand nodes provide the required coverage to distant nodes. Mathematical models are constructed for both problem specifications. Extensive computational results based on real data from Kartal (45 points) and Bakırköy (74 points) districts in Istanbul show that the proposed models are viable exact solution methodologies for moderate dimensions.Yazar, BaşakM.S

Managed access dependability for critical services in wireless inter domain environment

The Information and Communications Technology (ICT) industry has through the last decades changed and still continues to affect the way people interact with each other and how they access and share information, services and applications in a global market characterized by constant change and evolution. For a networked and highly dynamic society, with consumers and market actors providing infrastructure, networks, services and applications, the mutual dependencies of failure free operations are getting more and more complex. Service Level Agreements (SLAs) between the various actors and users may be used to describe the offerings along with price schemes and promises regarding the delivered quality. However, there is no guarantee for failure free operations whatever efforts and means deployed. A system fails for a number of reasons, but automatic fault handling mechanisms and operational procedures may be used to decrease the probability for service interruptions. The global number of mobile broadband Internet subscriptions surpassed the number of broadband subscriptions over fixed technologies in 2010. The User Equipment (UE) has become a powerful device supporting a number of wireless access technologies and the always best connected opportunities have become a reality. Some services, e.g. health care, smart power grid control, surveillance/monitoring etc. called critical services in this thesis, put high requirements on service dependability. A definition of dependability is the ability to deliver services that can justifiably be trusted. For critical services, the access networks become crucial factors for achieving high dependability. A major challenge in a multi operator, multi technology wireless environment is the mobility of the user that necessitates handovers according to the physical movement. In this thesis it is proposed an approach for how to optimize the dependability for critical services in multi operator, multi technology wireless environment. This approach allows predicting the service availability and continuity at real-time. Predictions of the optimal service availability and continuity are considered crucial for critical services. To increase the dependability for critical services dual homing is proposed where the use of combinations of access points, possibly owned by different operators and using different technologies, are optimized for the specific location and movement of the user. A central part of the thesis is how to ensure the disjointedness of physical and logical resources so important for utilizing the dependability increase potential with dual homing. To address the interdependency issues between physical and logical resources, a study of Operations, Administrations, and Maintenance (OA&M) processes related to the access network of a commercial Global System for Mobile Communications (GSM)/Universal Mobile Telecommunications System (UMTS) operator was performed. The insight obtained by the study provided valuable information of the inter woven dependencies between different actors in the delivery chain of services. Based on the insight gained from the study of OA&M processes a technological neutral information model of physical and logical resources in the access networks is proposed. The model is used for service availability and continuity prediction and to unveil interdependencies between resources for the infrastructure. The model is proposed as an extension of the Media Independent Handover (MIH) framework. A field trial in a commercial network was conducted to verify the feasibility in retrieving the model related information from the operators' Operational Support Systems (OSSs) and to emulate the extension and usage of the MIH framework. In the thesis it is proposed how measurement reports from UE and signaling in networks are used to define virtual cells as part of the proposed extension of the MIH framework. Virtual cells are limited geographical areas where the radio conditions are homogeneous. Virtual cells have radio coverage from a number of access points. A Markovian model is proposed for prediction of the service continuity of a dual homed critical service, where both the infrastructure and radio links are considered. A dependability gain is obtained by choosing a global optimal sequence of access points. Great emphasizes have been on developing computational e cient techniques and near-optimal solutions considered important for being able to predict service continuity at real-time for critical services. The proposed techniques to obtain the global optimal sequence of access points may be used by handover and multi homing mechanisms/protocols for timely handover decisions and access point selections. With the proposed extension of the MIH framework a global optimal sequence of access points providing the highest reliability may be predicted at real-time

Protection architectures for multi-wavelength optical networks.

by Lee Chi Man.Thesis (M.Phil.)--Chinese University of Hong Kong, 2004.Includes bibliographical references (leaves 63-65).Abstracts in English and Chinese.Chapter CHAPTER 1 --- INTRODUCTION --- p.5Chapter 1.1 --- Background --- p.5Chapter 1.1.1 --- Backbone network - Long haul mesh network problem --- p.5Chapter 1.1.2 --- Access network ´ؤ Last mile problems --- p.8Chapter 1.1.3 --- Network integration --- p.9Chapter 1.2 --- SUMMARY OF INSIGHTS --- p.10Chapter 1.3 --- Contribution of this thesis --- p.11Chapter 1.4 --- Structure of the thesis --- p.11Chapter CHAPTER 2 --- PREVIOUS PROTECTION ARCHITECTURES --- p.12Chapter 2.1 --- Introduction --- p.12Chapter 2.2 --- Traditional physical protection architectures in metro area --- p.13Chapter 2.2.1 --- Self healing ring --- p.17Chapter 2.2.2 --- Some terminology in ring protection --- p.13Chapter 2.2.3 --- Unidirectional path-switched rings (UPSR) [17] --- p.13Chapter 2.2.4 --- Bidirectional line-switched rings (BLSR) [17] --- p.14Chapter 2.2.5 --- Ring interconnection and dual homing [17] --- p.16Chapter 2.3 --- Traditional physical protection architectures in access networks --- p.17Chapter 2.3.1 --- Basic architecture in passive optical networks --- p.17Chapter 2.3.2 --- Fault management issue in access networks --- p.18Chapter 2.3.3 --- Some protection architectures --- p.18Chapter 2.4 --- Recent protection architectures on a ccess networks --- p.21Chapter 2.4.1 --- Star-Ring-Bus architecture --- p.21Chapter 2.5 --- Concluding remarks --- p.22Chapter CHAPTER 3 --- GROUP PROTECTION ARCHITECTURE (GPA) FOR TRAFFIC RESTORATION IN MULTI- WAVELENGTH PASSIVE OPTICAL NETWORKS --- p.23Chapter 3.1 --- Background --- p.23Chapter 3.2 --- Organization of Chapter 3 --- p.24Chapter 3.3 --- Overview of Group Protection Architecture --- p.24Chapter 3.3.1 --- Network architecture --- p.24Chapter 3.3.2 --- Wavelength assignment --- p.25Chapter 3.3.3 --- Normal operation of the scheme --- p.25Chapter 3.3.4 --- Protection mechanism --- p.26Chapter 3.4 --- Enhanced GPA architecture --- p.27Chapter 3.4.1 --- Network architecture --- p.27Chapter 3.4.2 --- Wavelength assignment --- p.28Chapter 3.4.3 --- Realization of network elements --- p.28Chapter 3.4.3.1 --- Optical line terminal (OLT) --- p.28Chapter 3.4.3.2 --- Remote node (RN) --- p.29Chapter 3.4.3.3 --- Realization of optical network unit (ONU) --- p.30Chapter 3.4.4 --- Protection switching and restoration --- p.31Chapter 3.4.5 --- Experimental demonstration --- p.31Chapter 3.5 --- Conclusion --- p.33Chapter CHAPTER 4 --- A NOVEL CONE PROTECTION ARCHITECTURE (CPA) SCHEME FOR WDM PASSIVE OPTICAL ACCESS NETWORKS --- p.35Chapter 4.1 --- Introduction --- p.35Chapter 4.2 --- Single-side Cone Protection Architecture (SS-CPA) --- p.36Chapter 4.2.1 --- Network topology of SS-CPA --- p.36Chapter 4.2.2 --- Wavelength assignment of SS-CPA --- p.36Chapter 4.2.3 --- Realization of remote node --- p.37Chapter 4.2.4 --- Realization of optical network unit --- p.39Chapter 4.2.5 --- Two types of failures --- p.40Chapter 4.2.6 --- Protection mechanism against failure --- p.40Chapter 4.2.6.1 --- Multi-failures of type I failure --- p.40Chapter 4.2.6.2 --- Type II failure --- p.40Chapter 4.2.7 --- Experimental demonstration --- p.41Chapter 4.2.8 --- Power budget --- p.42Chapter 4.2.9 --- Protection capability analysis --- p.42Chapter 4.2.10 --- Non-fully-connected case and its extensibility for addition --- p.42Chapter 4.2.11 --- Scalability --- p.43Chapter 4.2.12 --- Summary --- p.43Chapter 4.3 --- Comparison between GPA and SS-CPA scheme --- p.43Chapter 4.1 --- Resources comparison --- p.43Chapter 4.2 --- Protection capability comparison --- p.44Chapter 4.4 --- Concluding remarks --- p.45Chapter CHAPTER 5 --- MUL 77- WA VELENGTH MUL TICAST NETWORK IN PASSIVE OPTICAL NETWORK --- p.46Chapter 5.1 --- Introduction --- p.46Chapter 5.2 --- Organization of this chapter --- p.47Chapter 5.3 --- Simple Group Multicast Network (SGMN) scheme --- p.47Chapter 5.3.1 --- Network design principle --- p.47Chapter 5.3.2 --- Wavelength assignment of SGMN --- p.48Chapter 5.3.3 --- Realization of remote node --- p.49Chapter 5.3.3 --- Realization of optical network unit --- p.50Chapter 5.3.4 --- Power budget --- p.51Chapter 5.4 --- A mulTI- wa velength a ccess network with reconfigurable multicast …… --- p.51Chapter 5.4.1 --- Motivation --- p.51Chapter 5.4.2 --- Background --- p.51Chapter 5.4.3 --- Network design principle --- p.52Chapter 5.4.4 --- Wavelength assignment --- p.52Chapter 5.4.5 --- Remote Node design --- p.53Chapter 5.4.6 --- Optical network unit design --- p.54Chapter 5.4.7 --- Multicast connection pattern --- p.55Chapter 5.4.8 --- Multicast group selection in OLT --- p.57Chapter 5.4.9 --- Scalability --- p.57Chapter 5.4.10 --- Experimental configuration --- p.58Chapter 5.4.11 --- Concluding remarks --- p.59Chapter CHAPTER 6 --- CONCLUSIONS --- p.60LIST OF PUBLICATIONS: --- p.62REFERENCES: --- p.6