In MPLS networks, CR-LDP (Constraint-Based Routed Label Distribution Protocol) provides traffic engineering and QoS (Quality of Service) by distributing labels along the path. One of the innovative ideas in CR-LDP is right in the capability of bandwidth preemption. Bandwidth preemption allows a high-priority traffic flow to pre-empt the low-priority traffic flow when there is not enough bandwidth for conveying the high-priority flow. However, it is not effective in assuring QoS by simply pre-empting the low-priority flow. Therefore, in the thesis, we present a bandwidth preemption with negotiation (BPN) architecture for MPLS networks. In BPN, a high-priority flow will have to negotiate the bandwidth with Ingress Switch Router (ISR) before it can actually pre-empt the bandwidth being used by the low-priority flow. A network link-state database in ISR is designed to record the remaining bandwidth for each priority class. ISR determines whether a high-priority flow can pre-empt a low-priority flow based on the condition that the low-priority flow is possible to switch to other paths with an equal bandwidth along the path. In order to evaluate the performance of our proposed BPN mechanisms, we modify the MNS (MPLS Network Simulator) by adding a bandwidth negotiation module. For the comparisons, we design two topologies for simulating the proposed BPN and the traditional bandwidth preemption with force mode. It is observed that the BPN have exhibited better performance in average throughput and packet loss rate than the traditional bandwidth preemption, not matter either a complex or a regular topology is used. Finally, we analyze the BPN algorithm complexity by some network parameters, and compare the complexity with that of traditional bandwidth preemption

This thesis proposes a multi-protocol label switching (MPLS)-based architecture to provide quality of service (QoS) for both internet service provider (ISP) networks and backbone Internet Protocol (IP) networks that are heterogeneous in nature. Heterogeneous networks are present due to the use of different link-layer mechanisms in the current Internet. Copper-based links, fiber-based links, and wireless links are some examples of different physical media that lead to different link-layer mechanisms. The proposed architecture uses generalized MPLS and other MPLS features to combat heterogeneity. The proposed architecture leverages the QoS capabilities of asynchronous transfer mode (ATM) and the scalability advantages of the IP differentiated services (DiffServ) architecture. This architecture is constructed in such a way that MPLS interacts with DiffServ in the backbone networks while performing ATM-like QoS enforcement in the periphery of the networks. The architecture supports traffic engineering through MPLS explicit paths. MPLS network management, bandwidth broker capabilities, and customizability is handled through domain specific MPLS management entities that use the Common Open Policy Service (COPS) protocol to interact with other MPLS entities like MPLS label switch routers and label edge routers. The thesis provides a description of MPLS and QoS, followed by a discussion of the motivation for a new architecture. The MPLS-based architecture is then discussed and compared against similar architectures. To integrate the ATM and DiffServ QoS attributes into this architecture, MPLS signaling protocols are used. There are two common MPLS signaling protocols. They are Resource Reservation Protocol with traffic engineering extensions (RSVP-TE) and Constraint-Routed Label Distribution Protocol (CR-LDP). Both these protocols offer comparative MPLS features for constraint routed label switch path construction, maintenance, and termination. RSVP-TE uses UDP and IP, while CR-LDP uses TCP. This architecture proposes a multi-level domain of operation where CR-LDP operates in internet service provider (ISP) networks and RSVP- TE operates in backbone networks along with DiffServ. Qualitative analysis for this choice of domain of operation of the signaling protocols is then presented. Quantitative analysis through simulation demonstrates the advantages of combining DiffServ and MPLS in the backbone. The simulation setup compares the network performance in handling mixed ill-behaved and well-behaved traffic in the same link, with different levels of DiffServ and MPLS integration in the network. The simulation results demonstrate the advantages of integrating the QoS features of DiffServ, ATM functionality, and MPLS into a single architecture. / Master of Science

Multi-Protocol Label Switching (MPLS) emerged as a suitable solution to optimization of Internet Protocol (IP) networks. It improves network efficiency, utilization of resources and resilience in packet switched networks. With MPLS, packet forwarding decisions are made based on label inspection rather than packet header information. While MPLS is native to packet switched networks, Generalized Multiprotocol Label Switching (GMPLS) extends MPLS functionality to networks that support non-packet switched domains such as time, lambda and fiber. GMPLS also offers better resource management through the use of a new protocol; Link Management Protocol (LMP). In this work, a performance evaluation of GMPLS and MPLS control plane signaling protocols was performed. Further, a control plane interworking model for MPLS and GMPLS networks was proposed. Simulations were carried out to examine the performance of signaling protocols in an MPLS network configured with, and without Quality-of-Service (QoS). Conclusions on the performance characteristics of each signaling protocol were made based on the collected results.

Indiana University-Purdue University Indianapolis (IUPUI) / Multi-Protocol Label Switching (MPLS) is an emerging technology which is the initial step for the forthcoming generation of communication. It uses Labels in order to identify the packets unlike the conventional IP Routing Mechanism which uses the routing table at each router to route the packet. MPLS uses the techniques of FRR with the help of RSVP/CR-LDP to overcome the link and/or node failures in the network. On the other hand there are certain limitations/drawbacks of using the above mechanisms for Failure Detection and Recovery which are multiple protocols such as RSVP/CR-LDP over OSPF/IS-IS and complex algorithms to generate backup paths since each router works individually in order to create a backup tunnel. So to overcome the listed limitations, this paper discusses a new technique for MPLS Networks which is Source Routing \cite{48}. Source Routing is the technique in which the source plays the role of directing the packet to the destination and no other router plays the role of routing the packet in the network. Using the OPNET Modeler 17.5 tool for implementing source routing when there is a network failure is performed and the results are compared by implementing RSVP/CR-LDP over the same failed network. The comparative results show that the network performance is best in the case of Source Routing implementation as compared to the RSVP and CR-LDP signaling over the MPLS Networks.

In the modern era there exist applications that require very high resources and generate a tremendous amount of traffic so they require considerable amount of bandwidth and QOS to operate and perform correctly. MPLS is a new and a fast technology that offers much remuneration both in terms of providing trouble-free and efficient security together with the high speed of switching. MPLS not only guarantees quality of service of IP networks but in addition to provides scope for traffic engineering it offers many enhanced features of IP networks as it does not replace IP routing, but works along with existing and future routing technologies to provide high-speed data forwarding between label-switched routers (LSRs) together with QOS. Many network carriers are facing the problem of how to accommodate such ever-growing demands for bandwidth. And the static nature of current routing algorithms, such as OSPF or IS-IS, the situation is going even worse since the traffic is concentrated on the "least cost" paths which causes the congestion for some links while leaving other links lightly loaded. Therefore, MPLS traffic engineering is proposed and by taking advantage of MPLS, traffic engineering can route the packets through explicit paths to optimize network resource utilization and traffic performance. MPLS provides a robust quality of service control feature in the internet. MPLS class of service feature can work in accordance with other quality of service architectures for IP networks.