Patent ID: 8463966

Claim:
An initiator device for issuing transaction requests to a recipient device via an interconnect, said initiator device comprising: at least one port for receiving requests from and issuing requests to said interconnect; a barrier generator for generating barrier transaction requests, said barrier transaction requests indicating to said interconnect that an ordering of at least some transaction requests within a stream of transaction requests passing through said interconnect should be maintained by not allowing reordering of at least some of said transaction requests that occur before said barrier transaction request in said stream of transaction requests with respect to said barrier transaction request; wherein in response to receipt of a synchronise request querying progress of at least a subset of transaction requests, said initiator device is responsive to action any pending transaction requests within said at least a subset of transaction request and to generate a barrier transaction request at said barrier generator and to issue said barrier transaction request to said interconnect via said at least one port, and in response to receiving a response to said barrier transaction request to issue an acknowledge signal as a response to said synchronise request.