US Patent 7139860 On chip network with independent logical and physical layers

An OCN with independent logical and physical layers for enabling communication among integrated processing elements, including ports, bus gaskets and a physical layer interface. Each bus gasket includes a processor element interface and a port interface. Each processor element interface of at least two bus gaskets operates according to a first logical layer protocol. Each port interface operates according to a consistent port interface protocol by sending transaction requests and receiving acknowledgements and by sending and receiving packet datums via the corresponding port. The physical layer interface transfers packets between the ports and includes an arbiter and an interconnect coupled to each port. Additional bus gaskets may be added that operate according to a second logical layer protocol which may or may not be compatible with the first. Any bus gasket may be added that is configured to communicate using multiple logical layer protocols.