Patent ID: 9444611
Filing Date: 2016-09-13
CPC Classification: H04L

Claim Text:
1. A network system comprising: a switch configured to perform processes of a received packet in accordance with a flow entry in which are defined a rule and an action to uniformly control a packet as a flow; and a controller configured to transmit a control message to said switch to perform a setting of said flow entry, holds another flow entry identical to said flow entry set to said switch, manages a synchronization state per unity of a flow entry and preferentially synchronizes, in a case one of said flow entries is not synchronized, a specific flow entry between said switch, wherein each of said controller and said switch comprises: means configured to hold a flow table, wherein the flow table comprises a set of flow entries and is provided a column of synchronization flag for each flow entry and wherein the synchronization flag shows a synchronization state of a corresponding flow entry; means configured to hold a specific entry synchronization flag, wherein a part of the flow entries is the specific entry and wherein the specific entry synchronization flag shows a synchronization state of a specific entry; and means configured to update, in a case of detecting a communication interruption of a secure channel, values of synchronization flags and specific entry synchronization flags of all flow entries into “false”, wherein said controller further comprises: means configured to synchronize the specific entry when detecting the specific entry synchronization flag value to be “false” and to update, in respect to each of said controller itself and said switch, the values of the synchronization flag and specific entry synchronization flag of the synchronized specific entry into “true”; and means configured to synchronize, in a case the specific entry synchronization flag value is “true” and the packet the switch received and the specific entry does not match, a flow entry of which source and destination match with the received packet and updating, in respect to each of said controller itself and said switch, synchronization flag of synchronized flow entry into “true”.