Effect of inter-channel interference on IP traffic over WDM backbone networks

Convergence is forcing the network operating and switching speeds to Gigabit and more. WDM networks are becoming the de facto standard for IP backbone networks as they overcome the EMI issues associated with EM channels and switches. With its large bandwidth handling capabilities, the concept of IP traffic over optical WDM networks has become one of the most challenging topics to be considered. The issues arising out of mapping IP packets directly into WDM links using point-to-point protocol (PPP) encapsulation are discussed. While the magnitudes of EMI problems reduce with WDM, it emerges in a different form, albeit with lesser magnitude. One such challenge is the inter-channel interference (ICI), which is caused by non-linear effects of fiber focuses on the four-wave mixing (FWM) effect, which in turn affect the performance of the IP packet transmission. The characteristics of IP packet error is evaluated in terms of IP load, input light signal power and channel spacing. This paper suggests a possible solution to control the IP traffic load and improve channel spacing without affecting the overall network performance.