Conclusions

Optical WDM networks can be found throughout the network hierarchy. Due to various inefficiencies current SONET/SDH metro ring networks create the so-called metro gap which prevents high-speed packet switched LANs, access technologies, and service providers from tapping into the vast amounts of bandwidth available in the backbone. This bandwidth bottleneck at the metro level is anticipated to become more severe in the face of the ever increasing number of users and bandwidth-hungry applications and the steadily growing amount of local intra-MAN traffic.