I. Introduction
Wavelength-division multiplexing (wdm) is one of key technologies for Global Environment for Network Innovation (GENI) [1] (and the Future Internet). Since each wavelength can provide a data rate of 10 Gb/s or higher, while most experiments in GENI (or applications in the Future Internet) require only a subwavelength granularity, efficient WDM link virtualization and bandwidth sharing mechanisms are needed.