Patent ID: 7130614

Claim:
A method of attaching/updating a mobile unit to a cellular wireless communication network, said cellular wireless communication network comprising: a plurality of access network elements, each of which covering a respective cell area in said cellular wireless communication network, wherein said mobile unit is attached to one of said plurality of access network elements by means of a L2 type connection; and a plurality of routing network elements (AR 1 , AR 2 ) for forwarding data transmitted via said plurality of access network elements to and from said mobile unit, each of said routing network elements being connected with at least one of said plurality of access network elements, wherein said mobile unit is attached to one of said plurality of routing network elements by means of a L3 type connection, said method comprising the steps of initializing an attachment/update procedure of said mobile unit to one of said plurality of access network elements by means of a L2 type update procedure; transmitting from said mobile unit to said one of said plurality of access network elements a L3 type identification element indicating the existing attachment of said mobile unit to said one of said plurality of routing network elements; and checking said transmitted L3 type identification element for determining whether said one of said plurality of access network elements is provided with the connection to said one of said plurality of routing network elements to which the mobile unit has an existing attachment; and wherein in case that said one of said plurality of access network elements is provided with a connection to said one of said plurality of routing network elements to which the mobile unit has an existing attachment, the method comprises the step of completing the attachment/update procedure between said mobile unit and said one of said plurality of access network elements by means of executing the L2 type procedure and without executing a L3 type update procedure for an attachment of said mobile unit and the routing network elements.