Data delivery system with load distribution among data delivery units using shared lower address and unique lower layer address

A method for delivering data to clients from a system formed by a plurality of data delivery units, comprising the steps of:

• allocating a common upper layer address to said plurality of data delivery units;
• allocating to each data delivery unit a shared lower layer address common to said plurality of data delivery units and a unique lower layer address to be uniquely allocated to each data delivery unit;
• transferring a request destined to the upper layer address and transmitted from a client to said plurality of data delivery units;
• receiving at each data delivery unit a request from the client that is transferred to the shared lower layer address;
• transmitting from one data delivery unit which has a response right indicating one of said plurality of data delivery units which is allowed to respond to a request, a response which has the upper layer address as a source by using own unique lower layer address when a request received by the receiving step is a connection request that is made prior to data delivery;
• and
• transferring a response destined to the client and transmitted from one of said plurality of data delivery units toward the client.

A data delivery device among a plurality of data delivery devices for delivering data to clients in cooperation, comprising:

• a memory for storing an upper layer address which is commonly allocated to said plurality of data delivery devices:
• a first interface for holding a shared lower layer address commonly allocated to said plurality of data delivery devices, receiving a request destined to the upper layer address and transmitted from a client, and transmitting a response which has the upper layer address as a source by using the shared lower layer address when a received request is an address resolution request;
• and
• a second interface for holding a unique lower layer address uniquely allocated to said data delivery device among said plurality of data delivery devices, and transmitting a response which has the upper layer address as a source by using own unique lower layer address when a received request is a connection request that is made prior to data delivery and said data delivery device has a response right indicating one of said plurality of data delivery devices which is allowed to respond to requests.

An article of manufacture, comprising:

• a computer usable medium having computer readable program code means embodied therein for causing a computer to function as a data delivery device among a plurality of data delivery devices for delivering data to clients in cooperation, the computer readable program code means includes:
• first computer readable program code means for causing said computer to store an upper layer address which is commonly allocated to said plurality of data delivery devices:
• second computer readable program code means for causing said computer to hold a shared lower layer address commonly allocated to said plurality of data delivery devices, receive a request destined to the upper layer address and transmitted from a client, and transmit a response which has the upper layer address as a source by using the shared lower layer address when a received request is an address resolution request;
• and
• third computer readable program code means for causing said computer to hold a unique lower layer address uniquely allocated to said data delivery device among said plurality of data delivery devices, and transmit a response which has the upper layer address as a source by using own unique lower layer address when a received request is a connection request that is made prior to data delivery and said data delivery device has a response right indicating one of said plurality of data delivery devices which is allowed to respond to requests.

A data delivery system for delivering data to clients, comprising:

• a plurality of data delivery units, in which requests transmitted from a client including a connection request and a data delivery request are received by every data delivery unit and responses to requests are transmitted from one of said plurality of data delivery units toward the client, each data delivery unit including:
• a transmission unit capable of transmitting a first response to the connection request and a second response containing data requested by the data delivery request;
• and
• a processor for determining one data delivery unit which should transmit the second response among said plurality of data delivery units and commanding said one data delivery unit to transmit the second response, in a case where the transmission unit of said each data delivery unit transmitted the first response.

A method for delivering data to clients from a system formed by a plurality of data delivery units, the method comprising the steps of:

• receiving requests transmitted from a client including a connection request and a data delivery request by every data delivery unit;
• transmitting responses to requests from one of said plurality of data delivery units toward the client, where each data delivery unit is capable of transmitting a first response to the connection request and a second response containing data requested by the data delivery request;
• and
• determining one data delivery unit which should transmit the second response among said plurality of data delivery units and commanding said one data delivery unit to transmit the second response, at each data delivery unit which transmitted the first response.

A data delivery device among a plurality of data delivery devices for delivering data to clients in cooperation, comprising:

• a reception unit for receiving requests transmitted from a client including a connection request and a data delivery request which are to be received by every data delivery devices;
• a transmission unit capable of transmitting a first response to the connection request and a second response containing data requested by the data delivery request, where responses to requests are to be transmitted from one of said plurality of data delivery devices toward the client;
• and
• a processor for determining one data delivery device which should transmit the second response among said plurality of data delivery devices and commanding said one data delivery unit to transmit the second response, in a case where the transmission unit of said data delivery device transmitted the first response.

An article of manufacture, comprising:

• a computer usable medium having computer readable program code means embodied therein for causing a computer to function as a data delivery device among a plurality of data delivery devices for delivering data to clients in cooperation, the computer readable program code means includes:
• first computer readable program code means for causing said computer to receive requests transmitted from a client including a connection request and a data delivery request which are to be received by every data delivery devices;
• second computer readable program code means for causing said computer to function as a transmission unit of said data delivery device which is capable of transmitting a first response to the connection request and a second response containing data requested by the data delivery request, where responses to requests are to be transmitted from one of said plurality of data delivery devices toward the client;
• and
• third computer readable program code means for causing said computer to determine one data delivery device which should transmit the second response among said plurality of data delivery devices and command said one data delivery unit to transmit the second response, in a case where the transmission unit of said data delivery device transmitted the first response.