Wavelength Reuse for Efficient Transport of Variable-Size Packets in a Metro WDM Network

Metro WDM networks play an important role in the emerging Internet hierarchy; they interconnect the backbone WDM networks and the local access networks. The current SONET/SDH–over–WDM–ring metro networks are expected to become a serious bottleneck — the so–called metro gap — as they are faced with an increasing amount of bursty data traffic and quickly increasing bandwidths in the backbone networks and access networks. Innovative metro WDM networks that are highly efficient and able to handle variable–size packets are needed to alleviate the metro gap. In this paper we study an AWG–based single–hop WDM metro network. We analyze the photonic switching of variable–size packets with spatial wavelength reuse. We derive computationally efficient and accurate expressions for the network throughput and delay. Our extensive numerical investigations — based on our analytical results and simulations — reveal that spatial wavelength reuse is crucial for efficient photonic packet switching. In typical scenarios, spatial wavelength reuse increases the throughput by 60% while reducing the delay by 40%.