Load balancing

A method, for use in a load balancer of a communications network comprising a plurality of traffic servers, the method comprising:

• receiving a first Transmission Control Protocol (TCP) protocol data unit (PDU) generated by a client, the first TCP PDU comprising information indicating that the client is requesting an establishment of a TCP connection;
• after receiving the first TCP PDU selecting a traffic server;
• forwarding the received first TCP PDU to the selected traffic server, wherein the forwarded TCP PDU is identical to the received first TCP PDU;
• receiving a second TCP PDU that was generated by the client, wherein the second TCP PDU comprises a TCP header carrying an encoded identity of the traffic server;
• obtaining the encoded identity of the traffic server from the TCP header;
• and
• forwarding the received second TCP PDU to the traffic server as a result of determining that the second TCP PDU contains the encoded identity of the traffic server, wherein the forwarded second TCP PDU is identical to the received second TCP PDU, wherein
• obtaining the encoded identity of the traffic server from TCP header comprises obtaining the encoded identity of the traffic server from bits of TCP header reserved for carrying a time stamp value comprising least significant bits and most significant bits,
• obtaining the encoded identity of the traffic server from the bits of the TCP header reserved for carrying the time stamp value comprises reading a value identifying the traffic server from bits of the TCP header reserved for carrying the least significant bits of the time stamp value, and
• the least significant bits of the time stamp value are carried in the bits of the TCP header reserved for carrying the most significant bits of the time stamp value.

A method, the method comprising:

• a traffic server receiving a first Transmission Control Protocol (TCP) protocol data unit (PDU) that was transmitted by a client towards an origin server, wherein the first TCP PDU comprises a TCP header comprising:
• i) a first set of N bits encoding a timestamp, wherein the first set of N bits consists of M least significant bits (LSBs) and L most significant bits (MSBs) and ii) a second set of N bits consisting of L bits that encode a traffic server identifier that identifies the traffic server and M other bits, wherein M+L=N;
• the traffic server generating a second TCP PDU that is a modified version of the first TCP PDU, wherein generating the second TCP PDU comprises generating a third set of N bits that consists of i) the L bits of the second set of N bits that encode the traffic server identifier and ii) the M LSBs of the first set of N-bits, wherein the second TCP PDU comprises a TCP header that contains the third set of N bits;
• and
• the traffic server transmitting the second TCP PDU towards the origin server.

A load balancer for use in a communications network comprising a plurality of traffic servers, the load balancer comprising:

• a receiver configured to receive a first Transmission Control Protocol (TCP) protocol data unit (PDU) generated by a client, the first TCP PDU comprising information indicating that the client is requesting an establishment of a TCP connection;
• a transmitter;
• a memory;
• and
• a processor coupled to the memory, the receiver, and the transmitter, wherein
• the load balancer is configured to:
• after receiving the first TCP PDU, select a traffic server;
• forward the received first TCP PDU to the selected traffic server, wherein the forwarded TCP PDU is identical to the received first TCP PDU;
• receive a second TCP PDU that was generated by the client, wherein the second TCP PDU comprises a TCP header carrying an encoded identity of the traffic server;
• obtain the encoded identity of the traffic server from bits of the TCP header reserved for carrying a time stamp value comprising least significant bits and most significant bits;
• and
• forward the received second TCP PDU to the traffic server as a result of determining that the second TCP PDU contains the encoded identity of the traffic server, wherein the forwarded second TCP PDU is identical to the received second TCP PDU, wherein
• the load balancer is configured to obtain the encoded identity of the traffic server from bits of the TCP header reserved for carrying the least significant bits of the time stamp value, and
• the least significant bits of the time stamp value are carried in bits of the TCP header reserved for carrying the most significant bits of the time stamp value.

A traffic server, the traffic server comprising:

• a receiver for receiving a first Transmission Control Protocol (TCP) protocol data unit (PDU) that was transmitted by a client towards an origin server, wherein the first TCP PDU comprises a TCP header comprising:
• i) a first set of N bits encoding a timestamp, wherein the first set of N bits consists of M least significant bits (LSBs) and L most significant bits (MSBs) and ii) a second set of N bits consisting of L bits that encode a traffic server identifier that identifies the traffic server and M other bits, wherein M+L=N;
• a transmitter;
• a memory;
• and
• a processor coupled to the memory, the receiver, and the transmitter, wherein
• the traffic server is configured to:
• generate a second TCP PDU that is a modified version of the first TCP PDU, wherein generating the second TCP PDU comprises generating a third set of N bits that consists of i) the L bits of the second set of N bits that encode the traffic server identifier and ii) the M LSBs of the first set of N-bits, wherein the second TCP PDU comprises a TCP header that contains the third set of N bits;
• and
• transmit the second TCP PDU towards the origin server.