POLITECNICO DI TORINO III Facoltà di Ingegneria Corso di laurea in Ingegneria Informatica DIFFERENTIATION. Gianpaolo Campiglia - PDF


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POLITECNICO DI TORINO III Facoltà di Ingegneria Corso di laurea in Ingegneria Informatica IP/MPLS over ASON/GMPLS networks EXTENSION OF THE GMPLS CONTROL PLANE FOR THE MULTILAYER SERVICE DIFFERENTIATION Gianpaolo Campiglia Relatore: Prof. Marco Mellia Promotors: Prof. Dr. Ir. Kris Steenhaut Prof. Dr. Ann Nowé Supervisors: Walter Colitti Pasquale Gurzì This final project was realized within the framework of the Erasmus exchange programme between Universitat Politècnica de Catalunya, Vrije Universiteit Brussel, Politecnico di Torino and submitted in partial fulfillment of the requirements for the master degree in Computer Science Engineering. List of Acronyms ASON Automatically Switched Optical Network ATM Asynchronous Transfer Mode CC Connection Controller CoS Class of Service DCN Data Communication Network FA Forwarding Adjacency FSC Fiber Switching Capable GLR Generalized Label Request GMPLS Generalized Multi Protocol Label Switching GUI Graphical User Interface IETF Internet Engineering Task Force IGP Interior Gateway Protocol IP Internet Protocol IPoWDM IP over WDM IPTV IP Television ISO International Standard Organization ITU T International Telecommunication Union Telecommunication Standardization Bureau LIB Label Information Base LRM Link Resource Manager LSC Lambda Switching Capable LSP Label Switched Path MPλS Multi Protocol Lamda Switching MPLS Multi Protocol Label Switching MT Multi Topology MTE Multilayer Traffic Engineering OADM Optical Add Drop Multiplexer OAM&P Operations, Administration, Maintenance, and Provisioning OC Optical Carrier OEO Optical Electronic Optical OIF Optical Internetworking Foundation OSI Open Systems Interconnection OSPF Open Shortest Path First OXC Optical Cross Connect PSC Packet Switching Capable QoS Quality of Service RSVP Resource reservation Protocol RSVP TE Resource reservation Protocol Traffic Engineering RWA Routing and Wavelength Assignment SDH Synchronous Digital Hierarchy SLA Service Level Agreement SLRC Single Layered Route Computation TE Traffic Engineering TED Traffic Engineering Database TLRC Two Layered Route Computation UNI User to Network Interface WADM Wavelength Add Drop Multiplexer WDM Wavelength Division Multiplexing SONET Synchronous Optical NETwork SPF Shortest Path First TDM Time Division Multiplexing Chapter 1 Introduction Contents 1 Introduction Organization of the Thesis ASON/GMPLS Overview IPoWDM IPoWDM Network Architechture Control Plane Integration ASON ASON Control Plane GMPLS Traffic Engineering in IPoWDM Networks Multilayer TE with ASON/GMPLS routers (MTE) On Line Traffic Engineering Service Differentiation Service Differentiation: the evolution towards modern scenarios Multi Layer Traffic Engineering Policies (MTE) Virtual Topology First (VT F) Policy Physical Topology First (PTF) Policy Service Differentiation policies Routing Policy Differentiation (RP Diff) Virtual Topology Hard Differentiated Service (VT HardDiff) Virtual Topology Soft Differentiated Service (VT SoftDiff) GMPLS Protocols for Service Differentiation OSPF Overview... 40 Chapter 1 Introduction Areas Type of Router OSPF Functionalities OSPF Type of Packets The OSPF Protocols The Opaque LSA Option The Opaque LSA Flooding Opaque LSAs Traffic Engineering Extensions to OSPF (OSPF TE) Traffic Engineering LSAs (TE LSA) TE LSA Header TE LSA Payload Sub TLVs Details Multi Topology Routing in OSPF (OSPF MT) Multi Topology Routing vs. TOS Based Routing Protocol Extensions for Multi Topology Shortest Path Calculation Default Topology Link Exclusion Capability Working Environment: ASON/GMPLS Simulation Tool OMNet Modelling Concepts Building and Running simulations Analyzing Simulation Results The INET Framework IP/MPLS over ASON/GMPLS Simulation Tool... 66 Chapter 1 Introduction Statistics Collector Connection Generator Network GMPLS Node Setup Handler Physical Layer Control Layer Virtual Layer Simulator Extensions Chapter overview and Goal of this work Simulator Extensions Link State Module Implementation Steps OSPF Integration OSPF C++ Classes Interface classes IMessageHandler classes Neighbor classes OSPFLSA Classes OSPF TE Link TLVs OSPF TE Implementation The OSPFPacket class OSPFNeighbor class OSPFMessageHandler classes Synchronizing TED and TE LSA Database Chapter 1 Introduction 6.6 OSPF MT The RFC 4915 approach Connection Request accommodation Calculating the Shortest Path Virtual TED updating Simulation Study System model and simulation settings NetworkTopology Traffic Model Simulation Settings OSPF Timers and protocol blocking probability issues TCP/UDP Traffic Simulation Network Model Standard Host implementation Simulation Settings Simulations Analysis Conclusions Chapter 1 Introduction Chapter 1 Introduction Abstract Transport networks have moved towards a model called Automatically Switched Optical Network (ASON) controlled by the Generalized Multi protocol Label Switching (GMPLS) control plane. An ASON/GMPLS network is an intelligent optical network providing the Internet Protocol (IP)/Multi Protocol Label Switching (MPLS) layer with dynamic and distributed connection provisioning. In the IP/MPLS layer the service differentiation has become necessary to cope with the aggregation of various services, including performance sensitive as well as best effort applications. The Differentiated Services (DiffServ) technology has become quite mature in IP/MPLS domains and the research world has recently made an effort to extend it within the ASON/GMPLS layer. In [14] the DiffServ is executed in a multilayer fashion by means of a technique called virtual topology differentiation. This technique allows different Classes of Service (CoS) to be accommodated over independent virtual topologies and with different multilayer routing policies. The authors demonstrate how different CoS are provided with different levels of QoS. However, the extension of the GMPLS control plane for the introduction of the DiffServ in IP/MPLS over ASON/GMPLS networks is not addressed. This thesis addresses the problem of multilayer service differentiation in IP/MPLS over ASON/GMPLS network focusing on the GMPLS control plane. We start from the Multi Topology (MT) routing technique used in the Open Shortest Path First (OSPF) protocol to address the MT problem in IP networks. We first make the suitable adaptation to employ this technique in the GMPS control plane as well. The extended MT technique is then implemented in an IP/MPLS over ASON/GMPLS simulator. We finally use the extended simulator to simulate three strategies introduced in [14] in order to make an analysis of the multilayer service differentiation. Chapter 1 Introduction Introduction P a g e 1 Chapter 1 Introduction Since its birth, the Internet has been continuously growing at an exceptional exponential rate. Many companies interested in this phenomenon have been studying for years the traffic growth of the global network mainly to foresee and plan upgrades of the Internet devices, such as switches and routers, and transmission mediums. IP networks today carry traffic of different types, characteristics, and performance requirements. According to [25], the total IP traffic will almost double every 2 years through 2011 with a yearly increasing rate of about 46%. In [25], the authors also illustrates how the different consumer applications will be influencing the growth of the Internet traffic in the next years. Figure 1.1 IP Traffic Growth by subsegment P a g e 2 Chapter 1 Introduction As shown in Figure 1.1, over the last few years the main driving forces of the Internet traffic growth have been the commercial video service, or IP Television (IPTV), the Voice over IP service (VoIP) and the Internet video and multimedia applications (such as You Tube). Actual networks accommodate several types of applications, ranging from realtime and streaming, to bandwidth guaranteed, to traditional best effort applications. As result of a general convergence over the IP technology of most of the services offered by internet providers, IP networks are being actually used to deliver bundled services that include performance sensitive applications, such as voice and video, as well as the so called best effort data services. Large enterprises also rely heavily on IP networks to transfer a mix of both critical (e.g., data center backup) and non critical data for their business needs. To support this traffic aggregation, service differentiation is necessary, driving the network evolution towards transport infrastructures enabling the provisioning of connections with certain Quality of Service (QoS) guarantees, such as high bandwidth, low endto end delay, low delay jitter and minimal losses. For instance, Real time applications require the utilization of real time channels, which must be set up with specific traffic characteristics and QoS satisfying requirements. Thus, the time required to set up an end to end real time channel is one of the fundamental metrics to be taken into consideration in real time applications. Transport networks are moving towards a model of high performance Internet Protocol/Multi Protocol Label Switching (IP/MPLS) routers interconnected through intelligent backbones, which directly provide an infrastructure for new IP services that are compatible with existing IP services [26]. In order to optimize the routing for the expected traffic demand, network operators often employ traffic engineering (TE) algorithms to determine the paths, which are then implemented using shortest path routing protocols, such as OSPF or IS IS. MPLS improves the IP layer Traffic Engineering by means of the fast label switching technology that creates connection oriented Label Switching Paths (LSPs). Below the IP/MPLS layer, optical fiber using Wavelength Division Multiplexing (WDM) technique is the most promising wire line technology, offering an enormous network capacity. An IP over WDM network is designated for the transmission of IP traffic in a P a g e 3 Chapter 1 Introduction WDM enabled optical network to leverage both IP universal connectivity and massive WDM bandwidth capacity [27]. There are different types of IPoWDM control architectures which differ in their dynamic capabilities, configurations and the interactions between the IP and the optical control plane. An IPoWDM network supports emerging requirements such as dynamic and rapid provisioning of connections, automatic topology discovery, reactive Traffic Engineering and fast restoration. A key issue to achieve these functionalities is the definition of the optical control plane responsible for the routing and signaling processes. A first model of optical network with automatic switching capability has recently been standardized by the International Telecommunication Union, Telecommunication Standardization Sector (ITU T): the Automatic Switched Optical Network (ASON) [3]. While current optical networks only provide statically allocated transport capacity, the ASON dynamically sets up and tears down optical channels. To achieve this functionality the architecture of a control plane, which is responsible for the routing and signaling process, is defined. The Generalized Multi protocol Label Switching (GMPLS) set of protocols [1] has been widely recognized as the paradigm implementing the future ASON control plane. GMPLS is a networking specification standardized by Internet Engineering Task Force (IETF) [6]. GMPLS is a technology that provides enhancements to MPLS to support network switching for time, wavelength, and space switching as well as for packet switching. The Service Differentiation techniques and Traffic Engineering policies that provide load balancing for IP/MPLS networks can be extended and integrated with the ASON/GMPLS layer. This results in Multilayer Traffic Engineering (MTE) paradigm and integrated routing policies. These techniques allow the operator to accommodate service requests depending on their Class of Service (CoS), either in the IP/MPLS domain or in the optical domain, by aggregating traffic on the existing capacity or setting up new optical connections, respectively [14]. The choice of the Service Differentiation policies can influence the network performances from the operator s perspective (e.g, optimization of the network resources) and from the user s perspective (e.g., QoS offered). In [14] the DiffServ is executed in a P a g e 4 Chapter 1 Introduction multilayer fashion by means of a technique called virtual topology differentiation. This technique allows different Classes of Service (CoS) to be accommodated over independent virtual topologies and with different multilayer routing policies. Routing Policy Differentiation (RP Diff) scheme. This approach consists of a simple algorithm where the MTE routing policy is established on the base of the CoS the service request belongs to. Virtual Topology Hard Differentiation (VT HardDiff) scheme. Traffic belonging to different CoS is accommodated over separated lightpaths (OLSPs). Therefore, different virtual topologies will be formed by different set of OLSPs accommodating different CoS. The virtual topologies are independent from each other, thus different routing policies can be used to accommodate traffic, without sharing any resource. Virtual Topology Soft Differentiation (VT SoftDiff) scheme. This approach follows the same schema of VT HardDiff. However, a certain degree of resource sharing is introduced. This allows virtual topologies to share part of the established OLSPs. This thesis addresses the problem of multilayer service differentiation in IP/MPLS over ASON/GMPLS network focusing on the GMPLS control plane. We start from the Multi Topology (MT) routing technique used in the Open Shortest Path First (OSPF) protocol to address the MT problem in IP networks. We first make the suitable adaptation to employ this technique in the GMPS control plane as well. The extended MT technique is then implemented in an IP/MPLS over ASON/GMPLS simulator previously developed at the Vrije Universiteit Brussel [7]. The simulation framework used by the IP/MPLS over ASON/GMPLS simulator is OM NeT++. This engine is commonly used for network simulations because of the availability of the INET Framework [21] that is a collection of OMNeT++ modules [22], ready to be used, implementing different protocols of the Open Systems Interconnection (OSI) stack. In particular, the INET s OSPF module has been suitably extended for the implementation of the Multi Topology capability and the Service Differentiation policies listed above. After elaborating on the design and implementation of the simulator, the thesis presents an extensive set of experiments. The experiments focus on two of the key metrics used P a g e 5 Chapter 1 Introduction to evaluate the QoS provided by networks to time sensitive applications: blocking probability and packet delay. 1.1 Organization of the Thesis Some theoretical basics are needed to properly understand the development of this work. For this reason, the first sections of this thesis explain basic concepts about the topic we are talking about. Chapter 2 presents a description of the modern optical networks, introducing the internet working model used in the development of the ASON/GMPLS router simulator. ASON control plane is introduced together with its natural paradigm GMPLS. Chapter 3 introduces the Service Differentiation, which is the main topic of this work. First, a brief overview about the state of the art is presented, followed by a description of two commonly used MTE routing policies: VT F and PT F. The second part of this section presents finally three different algorithms that will be implemented in our simulator, in order to test their performances under the Service Differentiation perspective: Routing Policy Differentiation, Virtual Topology Hard Differentiation and Virtual Topology Hard Differentiation, designed in [14]. Chapter 4 gives an overview over the preliminary study over the protocols needed to properly implement the Multi Topology routing and the Service Differentiation algorithms introduced before. Traffic Engineering and Multi Topology extensions to the OSPF are defined. This is an important part of the thesis, giving the protocol basics to implement the MT routing within a realistic IP/MPLS over ASON/GMPLS simulator. Specifications given in this chapter will be then followed during the implementation stage of this work. In chapter 5, the OMNeT++ simulation engine is described to let the reader understand how a network model is implemented and how it behaves during simulations. In the second part of the chapter the INET Framework is introduced and, in particular, we focus on the description of the available simulation tool that represents the starting point of our work. P a g e 6 Chapter 1 Introduction Chapter 6 gives implementation details over the simulator extensions. Firstly the goal of the thesis is shown and the simulator is described from the point of view of the OM NeT++ modules. Configuration files and interaction between the modules are also described. In the second part of this chapter our IP/MPLS over ASON/GMPLS simulator extensions are explained from a lower abstraction point of view. The main steps covered during the implementation stage are described, together with the main implemented C++ classes, their methods and variables. When needed, the chapter focuses on how the two layers inside each router are synchronized to enable Multi Layer Traffic Engineering and Service Differentiation when setting up a connection. Chapter 7 presents an extensive set of experiments carried out using our final simulator in order to achieve some important goals: Evaluate the contribution to the Service Differentiation given by the MT routing approach proposed in [14], applied to a realistic IP/MPLS over ASON/GMPLS environment. Compare the results obtained simulating the three Service Differentiation algorithms. Also, a brief description of the traffic model implemented, some further OMNET++ modules added to the simulator and their implementation is given. Finally, Chapter 8 gives some conclusions on the experiments results and the simulator development. Future enhancements and developments of the simulator are also suggested. P a g e 7 P a g e 8 Chapter 1 Introduction Chapter Chapter 2 ASON/GMPLS 1 Introduction Overview ASON/GMPLS Overview P a g e 9 Chapter Chapter 2 ASON/GMPLS 1 Introduction Overview This chapter firstly presents some basics about IP over WDM technology. In particular it gives a brief introduction on the optical networks evolution and advantages. Then we will describe the architecture and the internetworking model adopted for the creation of an ASON/GMPLS router model that is the one used in this work. Afterwards we will focus on the optical network s control plane integration and description for an Automatically Switched Optical Network (ASON), going into depth in describing the ITU T G.8080 official architecture for it. Subsequently GMPLS protocols suite will be introduced to use it as ASON interfaces described in the ITU standard. In the last part of this chapter Traffic Engineering on Multi Layer networks is described and in particular online algorithms and grooming for traffic engineering are introduced. 2.1 IPoWDM It is widely believed that IP provides the only convergence layer in the global and ubiquitous Internet. IP, a layer 3 protocol, is designed to address network level interoperability and routing over different subnets with different layer 2 technologies. Above the IP layer, there are a great variety of IP based services and appliances that are still evolving. An example is IP based home networking interconnecting a wide range of electronic devices. Hence, the inevitable dominance of IP traffic makes apparent the engineering practices that the network infrastructure should be optimized for IP. Below the IP layer, optical fiber using WDM is the most promis
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