Network node and method of frame transfer

• US 6,188,689 B1
• Filed: 10/01/1997
• Issued: 02/13/2001
• Est. Priority Date: 10/04/1996
• Status: Expired due to Fees

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Yamato, Katsumi, Matsuzawa, Shigeo, Katsube, Yasuhiro
• Primary Examiner(s): Ton, Dang
• Assistant Examiner(s): Sam, Phirin
• Application Number:
  US08/941,735
• Time in Patent Office: 1,231 Days
• Field of Search: 370/389, 370/230, 370/231, 370/235, 370/252, 370/253, 370/299, 370/326, 370/327, 370/351, 370/359, 370/360, 370/382, 370/390, 370/392, 370/394, 370/395, 370/396, 370/397, 370/399, 370/400, 370/401, 370/402, 370/404, 370/405, 370/406, 370/420, 370/466, 370/467, 370/469, 370/474
• US Class Current: 370/389
• CPC Class Codes: H04L 12/4608 LAN interconnection over ATM networks
• CPC Class Codes: H04L 12/5601 Transfer mode dependent, e.g. ATM
• CPC Class Codes: H04L 49/251 Cut-through or wormhole routing
• CPC Class Codes: H04L 49/3009 Header conversion, routing tables or routing tags
• CPC Class Codes: H04L 49/351 for local area network [LAN], e.g. Ethernet switches
• CPC Class Codes: H04L 49/602 Multilayer or multiprotocol switching, e.g. IP switching
• CPC Class Codes: H04Q 11/0478 Provisions for broadband connections

Abstract

The system defines a dedicated virtual link (DVL) for a specified packet flow. The router receives a datalink frame having a Media Access Control (MAC) address field. An identifier of the DVL allocated between the router and a previous-hop node is written in the frame using the MAC address field. The router refers to a correspondence relationship between the identifier of the DVL and information for designating a next-hop node, based on the identifier of the DVL included in the received frame, and transfers the frame to the next-hop node without network-layer processing.

Claims

1. A node, comprising:

first means for transferring a connection-less type frame received from one logical network to another logical network by assembling a packet from the received frame and by referring to a destination network-layer address in the packet;

a memory for storing a correspondence relationship between an input dedicated virtual link identifier allocated dedicatedly to a specified flow and information for designating a next-hop node to which a frame of the specified flow is to be transferred;

second means for transferring a connection-less type frame received from one logical network to another logical network by referring to the correspondence relationship stored in the memory based on the input dedicated virtual link identifier written in the received frame using a Media Access Control (MAC) address field and by writing the information for designating the next-hop node in the frame to be transferred;

means for receiving a frame when the input dedicated virtual link identifier stored in the memory is written in the frame using a destination MAC address field,

and wherein the second means includes

means for referring to the correspondence relationship stored in the memory based on the input dedicated virtual link identifier written in the received frame using a destination MAC address field and writing the information designating the next-hop node in the frame to be transferred using the destination MAC address field;

means for creating a frame and writing the inout dedicated virtual link identifier in the created frame using a source MAC address field; and

means for transmitting the created frame with the input dedicated virtual link identifier to said one logical network so that a datalink switch in said one logical network obtains information for routing a frame based on a destination MAC address in the frame the destination MAC address corresponding to the input dedicated virtual link identifier.

2. The node according to claim 1, wherein the means for receiving includes

means for determining to receive the frame when the frame contains information indicating that the destination MAC address field is used for the input dedicated virtual link identifier.

3. The node according to claim 1, further comprising:

means for receiving a message inquiring about a MAC address;

means for responding to the message by sending an ATM address of the node when the inquired MAC address corresponds to the input dedicated virtual link identifier.

4. The node according to claim 1, wherein the second means includes

means for determining to transfer the frame by the second means when the frame contains information indicating that the MAC address field is used for the input dedicated virtual link identifier.

5. The node according to claim 1, wherein said another logical network is a connection-oriented network;

and

wherein the memory includes

a memory for storing a correspondence relationship between the information for designating the next-hop node and a virtual connection to be used for transferring a frame having the information for designating the next-hop node,

and the second means includes

means for transferring the frame having the information for designating the next-hop node onto the virtual connection.

6. The node according to claim 5, wherein the memory further includes

a memory for storing an output dedicated virtual link identifier allocated dedicatedly to the specified flow as or in addition to the information for designating the next-hop node,

and the second means further includes

means for using a virtual connection dedicated to the specified flow to transfer the frame having the output dedicated virtual link identifier.

7. The node according to claim 5, wherein the second means further includes

means for using a virtual connection to the next-hop node, the virtual connection shared by a plurality of flows, to transfer the frame having the information for designating the next-hop node.

8. The node according to claim 1, further comprising:

means for receiving/transmitting a message including information for identifying the specified flow and the input dedicated virtual link identifier allocated in said one logical network dedicatedly to the specified flow from/to said one logical network; and

means for registering the input dedicated virtual link identifier included in the message into the memory.

9. The node according to claim 1, further comprising:

means for transmitting/receiving a message including information for identifying the specified flow and an output dedicated virtual link identifier allocated in said another logical network dedicatedly to the specified flow to/from said another logical network; and

means for registering the output dedicated virtual link identifier included in the message into the memory as or in addition to the information for designating the next-hop node.

10. The node according to claim 1, further comprising:

a central control unit for referring to the destination network-layer address in the packet; and

means for associating a first section for receiving the frame from one logical network, a second section for transmitting the frame to another logical network, and the memory, separately from the central control unit,

and wherein the first means includes means for using the central control unit and the second means includes means for using the means for associating.

11. The node according to claim 1, further comprising:

a central control unit for referring to the destination network-layer address in the packet;

a bus for connecting a first section for receiving the frame from one logical network, a second section for transmitting the frame to another logical network, and the central control unit; and

a switch for connecting the first section and the second section,

and wherein the first means includes means for using the bus and the second means includes means for using the switch by referring to the memory.

12. The node according to claim 1, further comprising:

a central control unit for referring to the destination network-layer address in the packet; and

a switch for connecting a first section for receiving the frame from one logical network, a second section for transmitting the frame to another logical network, and the central control unit,

and wherein the first means includes means for using a virtual connection from the first section to the central control unit and a virtual connection from the central control unit to the second section via the switch, and the second means includes means for using the a virtual connection from the first section to the second section via the switch by referring to the memory.

13. A node, comprising:

first means for transferring a connection-less type frame received from one logical network to another logical network by assembling a packet from the received frame and by referring to a destination network-layer address in the packet;

a memory for storing a correspondence relationship between an input dedicated virtual link identifier allocated dedicatedly to a specified flow and information for designating a next-hop node to which a frame of the specified flow is to be transferred;

second means for transferring a connection-less type frame received from one logical network to another logical network by referring to the correspondence relationship stored in the memory based on the input dedicated virtual link identifier written in the received frame using a Media Access Control (MAC) address field and by writing the information for designating the next-hop node in the frame to be transferred;

means for receiving a frame when the input dedicated virtual link identifier stored in the memory is written in the frame using a destination MAC address fields

and wherein the second means includes

means for referring to the correspondence relationship stored in the memory based on the input dedicated virtual link identifier written in the received frame using a destination MAC address field and writing the information designating the next-hop node in the frame to be transferred using the destination MAC address field;

means for creating a frame and writing the input dedicated virtual link identifier in the created frame using a source MAC address field; and

means for transmitting the created frame with the input dedicated virtual link identifier through a virtual connection to a datalink switch in said one logical network so that the data link switch obtains information for transferring a received frame onto the virtual connection based on a destination MAC address in the frame, the destination MAC address corresponding to the input dedicated virtual link identifier.

14. The node according to claim 13, wherein the means for receiving includes

means for determining to receive the frame when the frame contains information indicating that the destination MAC address field is used for the input dedicated virtual link identifier.

15. The node according to claim 13, further comprising:

means for receiving a message inquiring about a MAC address;

means for responding to the message by sending an ATM address of the node when the inquired MAC address corresponds to the input dedicated virtual link identifier.

16. The node according to claim 13, wherein the second means includes

means for determining to transfer the frame by the second means when the frame contains information indicating that the MAC address field is used for input dedicated virtual link identifier.

17. The node according to claim 13, wherein said another logical network is a connection-oriented network;

and

wherein the memory includes;

a memory for storing a correspondence relationship between the information for designating the next-hop node and a virtual connection to be used for transferring a frame having the information for designating the next-hop node,

and the second means includes

means for transferring the frame having the information for designating the next-hop node onto the virtual connection.

18. The node according to claim 17, wherein the memory further includes

a memory for storing an output dedicated virtual link identifier allocated dedicatedly to the specified flow as or in addition to the information for designating the next-hop node,

and the second means further includes

means for using a virtual connection dedicated to the specified flow to transfer the frame having the output dedicated virtual link identifier.

19. The node according to claim 17, wherein the second means further includes

means for using a virtual connection to the next-hop node, the virtual connection shared by a plurality of flows, to transfer the frame having the information for designating the next-hop node.

20. The node according to claim 13, further comprising:

means for receiving/transmitting a message including information for identifying the specified flow and the input dedicated virtual link identifier allocated in said one logical network dedicatedly to the specified flow from/to said one logical network; and

means for registering the input dedicated virtual link identifier included in the message into the memory.

21. The node according to claim 13, further comprising:

means for transmitting/receiving a message including information for identifying the specified flow and an output dedicated virtual link identifier allocated in said another logical network dedicatedly to the specified flow to/from said another logical network; and

means for registering the output dedicated virtual link identifier included in the message in to the memory as or in addition to the information for designating the next-hop node.

22. The node according to claim 13, further comprising:

a central control unit for referring to the destination network-layer address in the packet; and

means for associating a first second for receiving the frame from one logical network, a second section for transmitting the frame to another logical network, and the memory, separately form the central control unit,

and wherein the first means includes means for using the central control unit and the second means includes means for using the means for associating.

23. The node according to claim 13, further comprising:

a central control unit for referring to the destination network-layer address in the packet;

a bus for connecting a first section for receiving the frame from one logical network, a second section for transmitting the frame to another logical network, and the central control unit; and

a switch for connecting the first section and the second section,

and wherein the first means includes means for using the bus and the second means includes means for using the switch by referring to the memory.

24. The node according to claim 13, further comprising:

a central control unit for referring to the destination network-layer address in the packet; and

a switch for connecting a first section for receiving the frame from one logical network, a second section for transmitting the frame to another logical network, and the central control unit,

and wherein the first means includes means for using a virtual connection from the first section to the central control unit and a virtual connection from the central control unit to the second section via the switch, and the second means includes means for using the a virtual connection from the first section to the second section via the switch by referring to the memory.

25. A method of frame transfer, comprising the steps of:

storing a correspondence relationship between an input dedicated virtual link identifier allocated in one logical network dedicatedly to a specified flow and information for designating a next-hop node in another logical network to which a frame of the specified flow is to be transferred;

transferring a frame received from one logical network to another logical network by referring to the correspondence relationship stored in the memory based on the input dedicated virtual link identifier written in the received frame using a MAC address field and by writing the information for designating the next-hop node in the frame to be transferred; and

transferring another frame received from one logical network to another logical network by assembling a packet from said another received frame and by referring to a destination network-layer address in the packet, when said another received frame does not contain the input dedicated virtual link identifier whose correspondence relationship is stored in the memory;

means for receiving a frame when the input dedicated virtual link identifier stored in the memory is written in the frame using a destination MAC address field,

and wherein the second means includes

means for referring to the correspondence relationship stored in the memory based on the input dedicated virtual link identifier written in the received frame using a destination MAC address field and writing the information designating the next-hop node in the frame to be transferred using the destination MAC address field;

means for creating a frame and writing the input dedicated virtual link identifier in the created frame using a source MAC address field; and

means for transmitting the created frame with the input dedicated virtual link identifier lo said one logical network so that a datalink switch in said one logical network obtains information for routing a frame based on a destination MAC address in the frame, the destination MAC address corresponding to the input dedicated virtual link identifier.

26. A method of frame transfer, comprising the steps of:

storing a correspondence relationship between an input dedicated virtual link identifier allocated in one logical network dedicatedly to a specified flow and information for designating a next-hop node in another logical network to which a frame of the specified flow is to be transferred;

transferring a frame received from one logical network to another logical network by referring to the correspondence relationship stored in the memory based on the input dedicated virtual link identifier written in the received frame using a MAC address field and by writing the information for designating the next-hop node in the frame to be transferred; and

transferring another frame received from one logical network to another logical network by assembling a packet from said another received frame and by referring to a destination network-layer address in the packet, when said another received frame does not contain the input dedicated virtual link identifier whose correspondence relationship is stored in the memory;

means for receiving a frame when the input dedicated virtual link identifier stored in the memory is written in the frame using a destination MAC address field,

and wherein the second means includes

means for referring to the correspondence relationship stored in the memory based on the input dedicated virtual link identifier written in the received frame using a destination MAC address field and writing the information designating the next-hop node in the frame to be transferred using the destination MAC address field;

means for creating a frame and writing the input dedicated virtual link identifier in the created frame using a source MAC address field; and

means for transmitting the created frame with the input dedicated virtual link identifier through a virtual connection to a datalink switch in said one logical network so that the data link switch obtains information for transferring a received frame onto the virtual connection based on a destination MAC address in the frame, the destination MAC address corresponding to the input dedicated virtual link identifier.