Switch and network bridge apparatus

An apparatus that is part of network system in a main system, the apparatus comprising:

• an internal network that resides in the apparatus;
• a first PCI express-network bridge which includes a first control unit and a first PCI express adapter which terminates a first PCI express bus;
• and
• a second PCI express-network bridge connected to the first PCI express-network bridge through said internal network, wherein the second PCI express-network bridge includes a second control unit and a second PCI express adapter which terminates a second PCI express bus,
• wherein said internal network, said first PCI express-network bridge, and said second PCI express-network bridge constitute a single PCI express switch,
• wherein the first control unit detects a destination of a packet sent from the first PCI express adapter, searches a packet encapsulating table for a physical address that corresponds to the destination, and encapsulates the packet in a frame so that the frame includes the physical address,
• wherein the second control unit removes the encapsulation tagged to the packet, and transfers the packet to the destination through the second PCI express bus by referring to a PCI express configuration register, and
• wherein the PCI express configuration register complies with a PCI express specification, whereby a configuration read/write packet is accessed, so that the main system regards said single PCI express switch as a conventional PCI express switch.

A method of controlling a network system that is a part of a main system, wherein the network system comprises an internal network that resides in the network system, a first PCI express-network bridge which includes a first control unit and a first PCI express adapter which terminates a first PCI express bus, and a second PCI express-network bridge connected to the first PCI express-network bridge through said internal network, wherein the second PCI express-network bridge includes a second control unit and a second PCI express adapter which terminates a second PCI express bus, wherein said internal network, said first PCI express-network bridge, and said second PCI express-network bridge constitute a single PCI express switch, the method comprising:

• detecting, at the first control unit, a destination of a packet sent from the first PCI express adapter;
• searching, at the first control unit, a packet encapsulating table for a physical address that corresponds to the destination;
• encapsulating, at the first control unit, the packet in a frame so that the frame includes the physical address;
• removing, at the second control unit, the encapsulation tagged to the packet;
• and
• transferring, at the second control unit, the packet to the destination through the second PCI express bus by referring to a PCI express configuration register, and
• wherein the PCI express configuration register complies with a PCI express specification, whereby a configuration read/write packet is accessed, so that the main system regards said single PCI express switch as a conventional PCI express switch.