This book reviews the challenges of all-optical and wireless networks for the future Internet, with a focus on cross-layer design and optimization. Features: presents a thorough introduction to major networking modes and their effect on Internet development; proposes a new structure favorable for all-optical packet switching; discusses a new quality of service (QoS) provisioning approach, which overcomes the scalability problem of IntServ and the coarse QoS granularity of DiffServ; describes the end-to-end arguments in Internet design, before investigating a solution to congestion control problems in multi-hop wireless and all-optical networks; examines how to exploit multiple-input-multiple-output technology to improve network performance in centralized wireless networks; surveys green networking strategies from a quantitative perspective; suggests a strategic vision for possible developments of network technology for the future Internet.