Multiprotocol label switching within the core network

The phenomenal growth of Internet traffic is attributed to the increasing a cceptance of the Internet protocol (IP) as the predominant protocol in ente rprise networks, The traditional design, of a router upon which the Interne t is based is becoming unable to support the current demand from users. Thi s service has worked exceptionally well for non real-time traffic such as e lectronic mail but for real-time traffic such as voice and video, IP has on ly performed well across a lightly loaded network. To provide services for real-time traffic, new classes of services art. being introduced into the I nternet. For networks to be able to support this increased user demand for more band width and for multimedia and real-time traffic, IP routers need to be faste r and to provide quality-of-service (QoS) guarantees. This demand for more bandwidth and QoS support has fuelled interest in the use of asynchronous t ransfer mode (ATM) as an underlying link-layer technology in the Internet. The aim is to exploit the potential benefits of ATM while maintaining the i nherent strengths of IP. Hop-by-hop routing normally works well for non-delay sensitive data traffic but, in cases where prioritisation is required, it gives unacceptable perf ormance since the current Internet is unable to differentiate between diffe rent sorts of packets, and thus stipulate that the network provide designat ed levels of servicing. Since voice and video are delay sensitive they will add additional pressure to the routers, Additionally the increase in traff ic is creating the need for higher bandwidth which the packet-forwarding mo del of router processing ;cannot provide effectively. The goal would be to expedite movement of information without forcing users to abandon router-in dependent protocols. Ideally, one would want to move the forwarding functio n of routing all the way out to the periphery of the network, leaving a pro tocol-independent network core that would be focused on providing:reliable high-performance standards-based connections. The emergence of the multiprotocol label switching (MPLS) architecture(1) a ims to improve the scalability and performance of the prevalent hop-by-hop routing and forwarding across packet networks. Its primary goal is to stand ardise a technology that integrates the label swapping forwarding paradigm with network layer routing. This label swapping is expected to improve the flexibility and robustness in. delivering new routing services without alte ration to the forwarding paradigm. The word multiprotocol suggests that thi s architecture will be applicable to any network-layer protocol In addition to IP; label switching indicates the underlying forwarding mechanism. This paper will start with a basic tutorial on IP switching techniques and then explain how it can be utilised to accelerate IP packets through the core o f the network. The paper concludes with the description of a proposed archi tecture, quality-of-sen,ice label distribution protocol (QoSLDP) whose obje ctive is to provide bandwidth guarantees.