The Optical Internetworking Forum has adopted four Physical and Link Layer Implementation agreements for tunable lasers; SFI-4, Phase 2, 10-Gb/s interface for physical layer devices; VSR4-05 OC-192 serial interface; and VSR5, SONET/SDH OC-768 interface. The tunable CW laser agreement has specified a common form, fit, interface and function for the subsystems, which may enable system and component vendors to reduce cost and increase interoperation. The forum approved four other agreements in 2002 to facilitate continuity and technological advances within the industry.