Common use of Initial Synchronization Message Exchange Sequence Clause in Contracts

Initial Synchronization Message Exchange Sequence. Hello is used by either controller or switch during connection setup for version negotiation. If the version negotiation fails, an Error message is sent with type HelloFailed. • Error message can be sent by either the switch or the controller and indicates the failure of an operation. All error messages begin with the standard OpenFlow header, containing the appropriate version and type values, followed by the error structure. Type indicates the high level nature of the error and the combination of type and code determines the detailed content of the error. • EchoReq/EchoRes is used to exchange information about latency, bandwidth and liveness. Echo request timeout indicates disconnection. • GetConfigReq/GetConfigRes/SetConfig are used to query and set the fragmentation handling properties of the packet processing pipeline. GetConfigReq is an acknowledged message (GetConfigRes) and is only initiated by the controller. SetConfig can only be initiated by the controller, and is unacknowledged. • FeatureReq/FeatureRes is used to implement feature determination. Controller sends a FeatureReq to the switch and then switch will respond with its capabilities. Besides the information included in OF specification, some extension has been proposed to report the capability of COSIGN new devices (as described in Table 31).

Initial Synchronization Message Exchange Sequence. Hello is used by either controller or switch during connection setup for version negotiation. If the version negotiation fails, an Error message is sent with type HelloFailed. • Error message can be sent by either the switch or the controller and indicates the failure of an operation. All error messages begin with the standard OpenFlow header, containing the appropriate version and type values, followed by the error structure. Type indicates the high level nature of the error and the combination of type and code determines the detailed content of the error. • EchoReq/EchoRes is used to exchange information about latency, bandwidth and liveness. Echo request timeout indicates disconnection. • GetConfigReq/GetConfigRes/SetConfig are used to query and set the fragmentation handling properties of the packet processing pipeline. GetConfigReq is an acknowledged message (GetConfigRes) and is only initiated by the controller. SetConfig can only be initiated by the controller, and is unacknowledged. • FeatureReq/FeatureRes is used to implement feature determination. Controller The controller sends a FeatureReq to the switch and then the switch will respond with its capabilities. Besides the information included in the OF specification, some extension has have been proposed to report the capability of COSIGN new devices (as described in Table 3139).