Connectionless ATM data services

Claim 2

Apparatus for transferring data messages, without establishing a connection between users, in an ATM system otherwise using established connections for data message transfers through a given network comprising a plurality of switching nodes (11), a plurality of user units (15) each connected to one of the switching nodes, and a network management center (17, 19), the apparatus comprising: A) means (43, 47, 53) for allocating a routing identifier RI to any user unit being activated at a specific network location for connectionless data transfer services; B) in each switching node of said network, table means (51, 53) including each allocated routing identifier RI and respective routing directions for correctly routing each message's cell containing a routing identifier RI, to the respective user unit; C) in the network management center, means (59, 61) for maintaining a global table including the address of each user unit activated for connectionless service, together with the allocated routing identifier RI, and means (55, 59) for updating this table each time a new routing identifier RI is allocated to a user unit; and D) in each user unit: D1) means (27, 31) for transmitting, when the user unit desires to send a data message in connnectionless mode to another user, a signalling message to said network management center requesting the destination user's routing identifier RI, D2) means (27, 33) for receiving, from said network management center in a signalling message the respective routing identifier RI if existing, and D3) means (21, 23, 33) for sending a data message to said other user by including said received routing identifier RI in the header of each cell of said message.

Claim 3

Method according to Claim 1, including the step of - providing each routing identifier RI in two-part form, the first part (RI-1) comprising an identification (SI) of the local switching node to which the respective user is connected, and the second part (RI-2) comprising an identification (PI) of the port within said local switching node to which the respective user is connected.

Claim 4

Method according to Claim 3, including the step of - providing in each switching node, a first table including in each entry a switching node identification (SI) of another node in the network, plus routing information for routing cells from the respective node holding said first table, to the node associated with said switching node identification.

Claim 5

Method according to Claim 3 or 4, including the step of - providing in each switching node, a second table including in each entry, the name of a local port to which a user is connected plus a port identification (PI) which is allocated to the respective user.

Claim 6

Method according to Claim 5, including the steps of - receiving a signalling message from a user for allocation of routing identifier RI, in the switching node to which said user is connected, - determining a free port identifier (PI), and entering this together with the name of the port where the user is connected, into said second table, - sending a signalling message containing the complete allocated routing identifier RI, including the respective switching node identification (SI), the newly allocated port identification (PI), and the respective user's address, to said central management function, and - entering the newly allocated routing identifier RI together with the user's address into said global table in the central management function.

Claim 7

Method according to Claim 1, for use in a system where each cell transferred through the network comprises in its header a field for a virtual path identification (VPI) and a field for a virtual circuit identification (VCI), including the step of - inserting a routing identifier RI into each cell which is to be transferred in connectionless mode, in the field provided for said virtual circuit identification (VCI).

Claim 8

Method according to Claim 1, for use in a system where each cell transferred through the network in connectionless mode comprises a field for a multiplexing identification (MID), said multiplexing identification carrying the same value in all cells belonging to the same message, including the step of - inserting into the multiplexing identification field (MID) of each cell transferred in connectionless mode, the routing identifier RI allocated to the source user sending the respective cell.

Claim 9

Method according to Claim 1, including for each user the steps of - entering a routing identifier RI received according to step D2, into a local table together with the respective destination user's address, - starting, with the sending of each data message to a destination user according to step D3, a timer associated with the respective entry in said local table, and - when the timer expires, invalidating the respective entry in said local table.

Claim 10

Apparatus according to Claim 2, wherein - said allocating means (43, 47, 53), table means (51, 53), and means for maintaining a global table (59, 61) are provided for routing identifiers RI in two-part form, including a first part (RI-1) for an identification (SI) of the local switching node to which the respective user is connected, and a second part (RI-2) for an identification (PI) of the port within said local switching node to which the respective user is connected.

Claim 11

Apparatus according to Claim 10, wherein - each switching node comprises a first table (51) including in each entry a switching node identification (SI) of another node in the network, plus routing information for routing cells from the respective node holding said first table, to the node associated with said switching node identification.

Claim 12

Apparatus according to Claim 10 or 11, wherein - each switching node comprises a second table (53) including in each entry, the name of a local port to which a user is connected plus a port identification (PI) which is allocated to the respective user.