TCP sequence number recovery in a redundant forwarding system

A network system operable to forward data within a computer network, the network system comprising:

• an active network device configured to forward data within the computer network;
• and
• a standby network device configured to replace the active network device when the active network device fails,
• wherein the active network device is operable to:
• send a first packet that forms part of a data connection, the first packet having a first send sequence number and the first packet being sent from the active network device to a receiver, wherein the data connection is a type of connection that tracks the sequence of data sent between the active network device and the receiver;
• receive a second packet having an associated first receive sequence number, and the second packet being received into the active network device from the receiver;
• send a third packet that forms part of the data connection from the active network device to the receiver, wherein the third packet has a second send sequence number;
• and
• communicate the first send sequence number and the first receive sequence number to the standby network device without communicating the second send sequence number to the standby network device.

A computer program product for forwarding data within a redundant system having an active network device and a standby network device, the computer program product comprising:

• at least one computer readable medium;
• computer program instructions stored within the at least one computer readable product configured to cause the redundant system to:
• send a first packet that forms part of a data connection, the first packet having a first send sequence number and the first packet being sent from the active network device to a receiver, wherein the data connection is a type of connection that tracks the sequence of data sent between the active network device and the receiver;
• receive a second packet having an associated first receive sequence number, and the second packet being received into the active network device from the receiver;
• send a third packet that forms part of the data connection from the active network device to the receiver, wherein the third packet has a second send sequence number;
• and
• communicate the first send sequence number and the first receive sequence number to the standby network device without communicating the second send sequence number to the standby network device.

An apparatus for forwarding data within a redundant system having an active network device and a standby network device, the apparatus comprising:

• means for sending a first packet that forms part of a data connection, the first packet having a first send sequence number and the first packet being sent from the active network device to a receiver, wherein the data connection is a type of connection that tracks the sequence of data sent between the active network device and the receiver;
• means for receiving a second packet having an associated first receive sequence number, and the second packet being received into the active network device from the receiver;
• means for sending a third packet that forms part of the data connection from the active network device to the receiver, wherein the third packet has a second send sequence number;
• and
• means for communicating the first send sequence number and the first receive sequence number to the standby network device without communicating the second send sequence number to the standby network device.