TUNNELLING OF MULTICAST DATA

摘要

A method of routing multicast data packets to a mobile node (1). The mobile node (1) forms part of a data transmission system comprising at least two access routers (2, 3) for providing data from at least one data source (4), the access routers (2,3) are arranged to be capable of wireless communication with the mobile node (1). The method comprises the steps of: determining that the mobile node (1) is to start communicating with a new access router (3) and to stop communicating with a previous access router (2); reporting to the previous address router (2), the multicast addresses currently being received by the mobile node, together with filtering rules associated therewith; providing to the mobile node (1) the new access router address (3); advising the previous access router (2) of the address of the next access router (3); controlling the previous access router (2) to initiate a handover to the new access router, the initiating including data representing the multicast addresses and associated filtering rules that the mobile node (1) is currently using; controlling the previous access router (2) to capture and buffer multicast packets of data which conform to the address and filtering rules; forwarding the buffered multicast packets to the new access router (3) from the previous access router; confirming connection between the new access router (3) and the mobile node (1); and forwarding from the new access router to the mobile node the buffered multicast packets.