Traffic Management for IP over WDM Networks

The ever-increasing growth of the current Internet traffic volume is demanding a bandwidth which can only be satisfied by means of optical technology. However, while WDM networks will bring an unprecedented amount of available bandwidth, traffic management techniques become necessary in order to make this bandwidth readily available to the end user. In this chapter we provide an overview of traffic management techniques for IP over WDM networks. More specifically, we address the following issues: i) Why is traffic management necessary in IP over WDM networks? and ii) What are the traffic management techniques currently proposed for IP over WDM? Concerning the first issue, we provide an intuitive, rather than mathematically concise, explanation about the specific features of Internet traffic that make IP traffic management particularly challenging. Internet traffic shows self-similarity features and there is a lack of practical network dimensioning rules for IP networks. On the other hand, the traffic demands are highly non-stationary and, therefore, the traffic demand matrix, which is the input for any traffic grooming algorithm, is timedependent. Furthermore, traffic sources cannot be assumed to be homogeneous, since very few users produce a large fraction of traffic. In dynamic IP over WDM networks we experience the problem of the multiservice nature of IP traffic. Since a myriad of new services and protocols are being introduced on a day-by-day basis it turns out that the provision of quality of service on demand becomes complicated. We analyze the service and protocol breakdown of a real Internet link in order to show the complexity of the dynamic QoS allocation problem. Regarding existing and proposed traffic management techniques we distinguish between static and dynamic WDM networks. Static WDM networks are dimensioned