This paper describes ILS (Inter-frame Link Signaling) that provides SDH/SONET (Synchronous Digital Hierarchy/Synchronous Optical NETwork) compatible OAM&P (Operations, Administration, Maintenance, and Provisioning) functions for 10 GbE (10-Gbit/s Ethernet) physical layer links. ILS transports OAM&P overhead bytes by replacing Idles in interframe gaps and organizes virtual frames to emulate SDH/SONET overhead transport. The ILS coding scheme has three features: 10 GbE PHY transparency, error detection ability, and disparity neutral characteristics. A 10 GbE LAN-PHY media converter, one-chip PHY LSI, and a XENPAK transceiver embedded with ILS have been developed in order to facilitate ILS implementation in optical network systems or Ethernet equipment. We confirmed ILS's feasibility through an experiment using the media converters and XENPAKs. The ILS can achieve highly reliable and cost-effective 10 GbE transport over optical networks.