Connectionless ATM data services

• US 5,432,777 A
• Filed: 12/16/1991
• Issued: 07/11/1995
• Est. Priority Date: 08/21/1991
• Status: Expired due to Term

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Le Boudec, Jean-Yves, Truong, Linh
• Primary Examiner(s): Hsu, Alpus
• Application Number:
  US07/807,359
• Time in Patent Office: 1,303 Days
• Field of Search: 370/54, 370/58.1, 370/58.2, 370/58.3, 370/60, 370/60.1, 370/85.13, 370/85.14, 370/94.1, 370/94.2, 370/94.3
• US Class Current: 370/397
• CPC Class Codes: H04L 2012/5645 Connectionless
• CPC Class Codes: H04L 2012/5652 Cell construction, e.g. including header, packetisation, depacketisation, assembly, reassembly
• CPC Class Codes: H04L 45/10 Routing in connection-oriented networks, e.g. X.25 or ATM
• CPC Class Codes: H04L 45/42 Centralised routing
• CPC Class Codes: H04L 49/254 Centralised controller, i.e. arbitration or scheduling
• CPC Class Codes: H04L 49/3009 Header conversion, routing tables or routing tags

Abstract

In a system using the Asynchronous Transfer Mode (ATM) for data transfers, each cell is usually routed in response to VPI/VCI values identifying a previously established connection. A connectionless transfer mode is disclosed by which to each requesting user, a unique routing identifier (RI) is allocated. All RIs allocated in the whole network are kept in a table of a routing identifier management function (RIMF). When a source user wants to send a message to a destination user, it requests the destination RI from the RIMF and inserts the received RI into each transmitted cell in the VCI field. The RI may, include a switching node identifier (SI) and a port identifier (PI). In that case, each switching node has a permanent table of all SIs plus respective routing information, and a changing table of all currently allocated PIs of locally connected users plus the respective user port names.

Claims

1. A method of transferring data messages, without establishing a connection between users, in an Asynchronous Transfer Mode system otherwise using established connections for data message transfers through a given network comprising switching nodes,

the method comprising the steps of:

A) allocating a routing identifier RI to any user being activated at a specific network location for connectionless data transfer services;

said routing identifier RI being in two-part form, the first part (RI-1) comprising an identification (S1) 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;

B) providing in each switching node of said network at least one table including at least a portion of each allocated routing identifier RI and respective routing directions for correctly routing a message cell containing a routing identifier RI, to the respective user;

C) providing in the network a central management function including a global table with the address of each user activated for connectionless service, together with the allocated routing identifier RI; and

D1) transmitting, by a source user desiring to send a data message in connectionless mode to another user, a signalling message with the destination user'"'"'s address to said central management function, requesting said destination user'"'"'s routing identifier RI,

D2) receiving, by said source user, from central management in a signalling message the respective routing identifier RI if existing, and

D3) sending, by the source user, a data message to said destination user by including said received routing identifier RI in the header of a message of said data message.

2. Method according to claim 1, 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.

3. A method of 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 switching nodes,

the method comprising the steps of:

A) allocating a routing identifier RI to any user being activated at a specific network location for connectionless data transfer services;

said routing identifier RI being in two-part form, the to 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;

B) providing in each switching node of said network a first table including at least a portion of 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;

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;

C) maintaining in a central management function of the network a global table including the address of each user activated for connectionless service, together with the allocated routing identifier RI; and

D1) transmitting, by a source user desiring to send a data message in connectionless mode to another user, a signalling message with the destination user'"'"'s address to said central management function, requesting said destination user'"'"'s routing identifier RI,

D2) receiving, by said source user, from central management in a signalling message the respective routing identifier RI if existing, and

D3) sending, by the source user, a data message to said destination user by including said received routing identifier RI in the header of a message of said data message.

4. A method of transferring data messages, without establishing a connection between users, in an Asynchronous Transfer Mode system otherwise using established connections for data message transfers through a given network comprising switching nodes,

the method comprising the steps of:

providing in each switching node of said network a first table including at least a portion of an allocated routing identifier RI and respective routing directions for correctly routing a message cell containing a routing identifier RI, to the respective user;

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;

providing, in the network a network center having a central management function with a global table including the address of each user activated for connectionless service, together with the allocated routing identifier RI;

receiving a signalling message from a user for allocation of routing identifier RI, in a 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 network center,

entering the newly allocated routing identifier RI together with the user'"'"'s address into said global table in the network center;

allocating a routing identifier RI to any user being activated at a specific network location for connectionless data transfer services;

said routing identifier RI being in a 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;

transmitting, by a source user desiring to send a data message in connectionless mode to another user, a signalling message with the destination user'"'"'s address to said central management function, requesting said destination user'"'"'s routing identifier RI,

receiving, by said source user, from central management in a signalling message the respective routing identifier RI if existing, and

sending, by the source user, a data message to said destination user by including said received routing identifier RI in the header of a message cell of said data message.

5. A method of transferring data messages, without establishing a connection between users, in a Asynchronous Transfer Mode system otherwise using established connections for data message transfers through a given network comprising switching nodes,

the method comprising the steps of:

A) allocating a routing identifier RI to any user being activated at a specific network location for connectionless data transfer services;

B) providing in each switching node of said network a table including at least a portion of each allocated routing identifier RI and respective routing directions for correctly routing a message cell containing a routing identifier RI, to the respective user;

C) providing, in a node of the network a central management function which includes, a global table including the address of each user activated for connectionless service, together with the allocated routing identifier RI; and

D1) transmitting, by a source user desiring to send a data message in connectionless mode to another user, a signalling message with the destination user'"'"'s address to said central management function, requesting said destination user'"'"'s routing identifier RI,

D2) receiving, by said source user, from the central management function in a signalling message the respective routing identifier RI if existing, and

D3) sending, by the source user, a data message to said destination user by including said received routing identifier RI in the header and into a multiplexing identification (MID) field of at least one cell of said data message.

6. A method of transferring data messages, without establishing a connection between users, in an Asynchronous Transfer Mode system otherwise using established connections for data message transfers through a given network comprising switching nodes,

the method comprising the steps of:

A) allocating a routing identifier RI to any user being activated at a specific network location for connectionless data transfer services;

B) providing in each switching node of said network at least one table including at least a portion of each allocated routing identifier RI and respective routing directions for correctly routing a message cell containing a routing identifier RI, to the respective user;

C) providing in the network a central management function including a global table with the address of each user activated for connectionless service, together with the allocated routing identifier RI; and

D1) transmitting, by a source user desiring to send a data message in connectionless mode to another user, a signalling message with the destination user'"'"'s address to said central management function, requesting said destination user'"'"'s routing identifier RI,

D2) receiving, by said source user, from central management, in a signalling message the respective routing identifier RI if existing,

D3) sending, by the source user, a data message to said destination user by including said received routing identifier RI in the header of a message of said data message; and

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.

7. Apparatus for transferring data messages, without establishing a connection between users, in an Asynchronous Transfer Mode 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) connected to each one of the switching nodes, and a network management center (17, 19), the apparatus comprising:

A) means (43, 47,

     53) associated with the switching nodes 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 at least a portion of each allocated routing identifier RI and respective routing directions for correctly routing a message 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;

said routing identifier RI being in two-part form, including a first part (I-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;

D) in each user unit;

D1) means (27,

     31) for transmitting, when the user unit desires to send a data message in connectionless 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 another user by including said received routing identifier RI in the header of at least one cell of said data message.

8. Apparatus according to claim 7, 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.

9. Apparatus for transferring data messages, without establishing a connection between users, in an Asynchronous Transfer Mode 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) associated with the switching nodes 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 at least a portion of each each allocated routing identifier RI and respective routing directions for correctly routing a message cell containing a routing identifier RI,

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; and

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;

said routing identifier RI being 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 to the respective user unit;

D) in each user unit;

D1) means (27,

     31) for transmitting, when the user unit desires to send a data message in connectionless 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 another user by including said received routing identifier RI in the header of at least one cell of said data message.

10. A method of transferring data messages, without establishing a connection between users, in an Asynchronous Transfer Mode system otherwise using established connections for data message transfers through a given network comprising switching nodes,

the method comprising the steps of:

A1) providing in each switching node of said network at least one table including at least a portion of each allocated routing identifier RI and respective routing directions for correctly routing a message cell containing a routing identifier RI, to the respective user;

A2) providing, in the network a network center with a global table including the address of each user activated for connectionless service, together with the allocated routing identifier RI;

B1) receiving a signalling message from a user for allocation of routing identifier RI, in a switching node to which said user is connected;

B2) determining a free port identifier (PI and entering this together with the name of the port where the user is connected into a second table,

B3) 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 network center,

B4) entering the newly allocated routing identifier RI together with the user'"'"'s address into said global table in the network center;

C1) transmitting, by a source user desiring to send a data message in connectionless mode to another user, a signalling message with the destination user'"'"'s address to said central management function, requesting said destination user'"'"'s routing identifier RI,

C2) receiving, by said source user, from a central management in a signalling message the respective routing identifier RI if existing, and

C3) sending, by the source user, a data message to said destination user by including said received routing identifier RI in the header of at least a message cell of said data message.

11. A method of transferring data messages, without establishing a connection between users, in an Asynchronous Transfer Mode network otherwise using established connections for data message transfers through a given network comprising switching nodes,

the method comprising the steps of:

A) allocating a routing identifier RI to any user being activated at a specific network location for connectionless data transfer services;

said routing identifier RI being 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;

B) providing in each switching node of said network at least one table including at least a portion of each allocated routing identifier RI and respective routing directions for correctly routing a message cell containing a routing identifier RI, to the respective user;

C) providing in the network a central management function including a global table with the address of each user activated for connectionless service, together with the allocated routing identifier RI; and

D1) transmitting, by a source user desiring to send a data message in connectionless mode to another user, a signalling message with the destination user'"'"'s address to said central management function, requesting said destination user'"'"'s routing identifier RI,

D2) receiving, by said source user, from the central management function in a signalling message the respective routing identifier RI if existing, and

D3) sending, by the source user, a data message to said destination user by including said received routing identifier RI in the header of at least one cell of said data message.

12. Apparatus for transferring data messages, without establishing a connection between users, in an Asynchronous Transfer Mode 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) associated with the switching nodes 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, said routing identifier RI being 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 for correctly routing a message cell containing a routing identifier RI, to the respective user unit;

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 table means to the node associated with said switching node identification

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 connectionless 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 another user by including said received routing identifier RI in the header of at least one cell of said data message.