Communications system for transmission of datagram packets over connection-oriented networks

• US 6,516,000 B1
• Filed: 04/29/1999
• Issued: 02/04/2003
• Est. Priority Date: 10/31/1995
• Status: Expired due to Term

• Current Assignee: Lucent Technologies, Inc. (Nokia Corporation)
• Original Assignee: Lucent Technologies, Inc. (Nokia Corporation)
• Inventors: Shur, David H., Woodworth, Clark, Kshirsagar, Madhukar M., Veeraraghavan, Malathi, La Porta, Thomas F.
• Primary Examiner(s): Patel, Ajit
• Assistant Examiner(s): Phunkulh, Bob A
• Application Number:
  US09/301,590
• Time in Patent Office: 1,377 Days
• Field of Search: 370/389, 370/390, 370/391, 370/392, 370/395, 370/396, 370/397, 370/398, 370/399, 370/400, 370/401, 370/409, 370/474, 370/410, 370/254, 370/255, 370/256
• US Class Current: 370/410
• CPC Class Codes: H04L 12/4608 LAN interconnection over ATM networks
• CPC Class Codes: H04L 2012/5626 Network management, e.g. Intelligent nets
• CPC Class Codes: H04L 2012/5645 Connectionless
• CPC Class Codes: H04L 2012/5667 IP over ATM
• CPC Class Codes: H04L 2012/5668 Next hop resolution protocol [NHRP]
• CPC Class Codes: H04Q 11/0478 Provisions for broadband connections

Abstract

A communications system for transporting connectionless datagrams over a connection-oriented network is arranged to remove the address resolution function and the connection setup function from a sending host and combine them in a third-party connection server in conjunction with channel management at connection-oriented routing points. The third party request protocol can be used for Classical connectionless over a connection oriented network, legacy LAN emulation and Routing Over Large Clouds.

Claims

1. A method of communicating connectionless datagrams between a connection-oriented source node and a connectionless destination node over a combination of a connection-oriented network, a connectionless network, and a network spanning node selected from the group consisting of a bridge and a router, said network spanning node having a first interface on said connection-oriented network, said network spanning node having a second interface on said connectionless network, said method comprising the steps of:

the source node checking its internal storage devices to determine the destination node'"'"'s connectionless address;

in the absence of an entry for the destination node'"'"'s connectionless address in the source node'"'"'s internal storage devices, transmitting a request to communicate from said connection-oriented source node to a connection request server, said request to communicate including a connectionless address of said connectionless destination node;

in response to said request to communicate, said communication request server resolving said destination node'"'"'s connectionless address and requesting the establishment of a connection in a single round trip communication between the transmitting source node and said communication request server by sending a first connection-oriented virtual channel identifier from said connection request server to said connection-oriented source node, said first connection-oriented virtual channel identifier corresponding to a first virtual channel between said connection-oriented source node and said network spanning node, said network spanning node utilizing said connectionless address to communicate with said connectionless destination node.

2. A method according to claim 1, further comprising the step of maintaining a list of existing virtual channels within said connection-oriented network, wherein said first virtual channel is selected from said list of existing virtual channels.

3. A method according to claim 1, further comprising the steps of:

said connection request server resolving said connectionless address into a connection-oriented address of said network spanning node; and

initiating a third-party connection set-up to establish said first virtual channel between said connection-oriented source node and said network spanning node.

4. A method according to claim 1, further comprising the steps of:

maintaining a list of one or more entries, each said entry associated with only one previously existing virtual channel within said connection-oriented network and with a virtual channel identifier corresponding to said previously existing virtual channel;

said connection request server resolving said connectionless address into a connection-oriented address of said network spanning node;

said connection request server checking said connection-oriented address of said network spanning node and a connection-oriented address of said connection-oriented source node against said list of existing virtual channels;

after said checking step, said connection request server deciding whether said list contains a first entry corresponding to said first virtual channel;

if said list does not contain said first entry, said connection request server initiating a third-party connection set-up to establish said first virtual channel.

5. A method according to claim 4, wherein said maintaining step is performed in said connection request server.

6. A method according to claim 5, further including the steps of:

sending said list from said connection request server to said network spanning node; and

releasing said first virtual channel after a predetermined period of inactivity of said first virtual channel.

7. A method according to claim 1, wherein said connectionless network is an ethernet network, and said connection-oriented network is an asynchronous transfer mode network.

20. A method according to claims 1, 8, 13, 15, or 18, further including the step of releasing said first virtual channel after a predetermined period of inactivity of said first virtual channel.

8. A method of communicating connectionless datagrams between a connectionless source node and a connection-oriented destination node over a combination of a connection-oriented network, a connectionless network, and a network spanning node selected from the group consisting of a bridge and a router, said network spanning node having a first interface on said connection-oriented network, said network spanning node having a second interface on said connectionless network, said method comprising the steps of:

sending a frame from said source node to said network spanning node;

maintaining a list of one or more entries, each said entry associated with only one previously existing virtual channel within said connection-oriented network and with a virtual channel identifier corresponding to said previously existing virtual channel;

resolving a connectionless address of said destination node into a connection-oriented address of said destination node;

checking said connection-oriented address of said destination node and a connection-oriented address of said network spanning node against said list of previously existing virtual channels in order to decide whether a first entry on said list exists, said first entry corresponding to a first virtual channel suitable for communicating said connectionless datagrams between said network spanning node and said destination node;

if said first entry does not exist, initiating a third-party connection set-up to establish said first virtual channel between said connection-oriented destination node and said network spanning node; and

transmitting said connectionless datagrams on said first virtual channel.

9. A method according to claim 8, further including the step of transmitting a request to communicate from said network spanning node to a connection request server, said request to communicate including a first address of said destination node.

10. A method according to claim 8, wherein said checking step is performed by said network spanning node.

11. A method according to claim 8, wherein said maintaining, checking, and initiating steps are performed by a connection request server.

12. A method according to claim 8, further including the step of sending said list from said connection request server to said network spanning node.

13. A method of communicating connectionless datagrams between a connectionless source node and a connectionless destination node over a combination of a connection-oriented network, a first connectionless network, a second connectionless network, a first network spanning node, and a second network spanning node, each network spanning node selected from the group consisting of a bridge and a router, said first network spanning node having a first interface on said connection-oriented network, said first network spanning node having a second interface on said first connectionless network, said second network spanning node having a first interface on said connection-oriented network, said second network spanning node having a second interface on said second connectionless network, said method comprising the steps of:

sending a first frame from said source node to said first network spanning node, said first frame including an address of said destination node;

transmitting a request to communicate from said first network spanning node to a connection request server, said request to communicate including said address of said destination node;

in response to said request to communicate, sending a first connection-oriented virtual channel identifier from said connection request server to said first network spanning node, said first connection-oriented virtual channel identifier corresponding to a first virtual channel between said first network spanning node and said second network spanning node;

sending subsequent frames from said second network spanning node to said destination node.

14. A method according to claim 13, further comprising the step of maintaining a list of existing virtual channels within said connection-oriented network, wherein said first virtual channel is selected from said list of existing virtual channels.

16. A method according to claims 13 or 15, wherein said first connectionless network is an ethernet network, said second connectionless network is an ethernet network, and said connection-oriented network is an asynchronous transfer mode network.

15. A method of communicating connectionless datagrams between a connectionless source node and a connectionless destination node over a combination of a connection-oriented network, a first connectionless network, a second connectionless network, a first network spanning node, and a second network spanning node, each network spanning node selected from the group consisting of a bridge and a router, said first network spanning node having a first interface on said connection-oriented network, said first network spanning node having a second interface on said first connectionless network, said second network spanning node having a first interface on said connection-oriented network, said second network spanning node having a second interface on said second connectionless network, said method comprising the steps of:

maintaining a list of one or more entries, each said entry associated with only one previously existing virtual channel within said connection-oriented network and with a virtual channel identifier corresponding to said previously existing virtual channel;

resolving a connectionless address on said second connectionless network of said second network spanning node into a connection-oriented address on said connection-oriented network;

sending a first frame from said source node to said first network spanning node, said first frame including an address of said destination node;

checking said connection-oriented address of said second network spanning node and a connection-oriented address of said first network spanning node against said list of previously existing virtual channels in order to decide whether a first entry on said list exists, said first entry corresponding to a first virtual channel suitable for communicating said connectionless datagrams between said first network spanning node and said second network spanning node;

if said first entry does not exist, initiating a third-party connection set-up to establish said first virtual channel between said first network spanning node and said second network spanning node; and

relaying subsequent frames from said second network spanning node to said destination node.

17. A method according to claim 15, wherein said maintaining, resolving, and checking steps are performed by said connection request server.

18. A method according to claim 15, wherein said maintaining and checking steps are performed by said connection request server, and said resolving step is performed by said first network spanning node.

19. A method according to claim 15, further including the step of sending said list from a connection request server to said first network spanning node.

21. A method of communicating connectionless datagrams between a connectionless source node and a connectionless destination node over a combination of a connection-oriented network, a first connectionless network, a second connectionless network, and a network spanning node selected from the group consisting of a bridge and a router, said network spanning node having a first interface on said first connectionless network, said network spanning node having a second interface on said second connectionless network, said network spanning node having a third interface on said connection-oriented network, said method comprising the steps of:

sending a first frame from said source node to said network spanning node, said first frame including a connectionless address of said destination node;

in response to said first frame, transmitting a request to communicate from said network spanning node to a connection request server, said request to communicate including said connectionless address of said destination node;

resolving said connectionless address on said second connectionless network of said network spanning node into a connection-oriented address of said network spanning node on said connection-oriented network;

sending a predetermined message from said connection request server to said network spanning node to cause said network spanning node to send subsequent frames on said second connectionless network, said subsequent frames being addressed to said destination node.

22. A method of communication connectionless datagrams between a source node and a destination node, said source node and said destination node residing on a connectionless network, said connectionless network overlaying a connection-oriented network, said source node having a first network prefix, said destination node having a second network prefix, said method comprising the steps of:

storing a connectionless-to-connection-oriented address mapping of said destination node with a first Next Hop Resolution Protocol-Connection Request Protocol (NHRP-CRP) server;

sending a request to communicate from said source node to said first NHRP-CRP server;

said request to communicate including a connectionless address of said destination node;

response to said request to communicate, resolving said connectionless address of said destination node into a connection-oriented address of said destination node;

transmitting from said first NHRP-CRP server to said source node a first virtual channel identifier of a first virtual channel between said source node and said destination node; and

said source node transmitting data frames to the destination node on said first virtual channel.

23. A method according to claim 22, further including the step of said first NHRP-CRP server initiating a third-party connection set-up to establish said first virtual channel between said source node and said destination node.

24. A method according to claim 23, wherein said sending step includes the steps of:

delivering said request to communicate to a second NHRP-CRP server;

said second NHRP-CRP server forwarding said request to communicate to said first NHRP-CRP server through regular procedures used by said connectionless network.

25. A method according to claim 24, wherein said forwarding step includes the step of said second NHRP-CRP server broadcasting said request to communicate to other NHRP-CRP servers existing on said connection-oriented network.

26. A method according to claim 24, wherein said initiating step includes the step of relaying a second virtual channel identifier to said destination node through a pre-registered hard-wired virtual channel identifier, said second virtual channel identifier corresponding to said first virtual channel.

27. A method according to claim 22, further including the step of releasing said first virtual channel after a predetermined period of inactivity of said first virtual channel.

28. A method of communicating connectionless datagrams between a source node and a destination node, said source node and said destination node residing on a connectionless network, said connectionless network overlaying a connection-oriented network and a connectionless subnetwork, said destination node residing on said connectionless subnetwork, said source node having a first network prefix, said destination node having a second network prefix, said method comprising the steps of:

storing a connectionless-to-connection-oriented address mapping of a network spanning node with a first Next Hop Resolution Protocol-Connection Request Protocol (NHRP-CRP) server, said network spanning node selected from the group consisting of a bridge and a router, said network spanning node having a first interface on said connection-oriented network, said network spanning node having a second interface on said connectionless subnetwork;

sending a request to communicate from said source node to said first NHRP-CRP server, said request to communicate including a connectionless address of said destination node;

in response to said request to communicate, resolving said connectionless address on said connectionless subnetwork of said network spanning node into its connection-oriented address;

transmitting to said source node a first virtual channel identifier of a first virtual channel between said source node and said network spanning node; and

said source node transmitting data frames to the network spanning node on said first virtual channel;

said network spanning node transmitting frames to the destination node.

29. A method according to claim 28, wherein said step of sending a request to communicate from said source to said first NHRP-CRP server includes the steps of:

delivering said request to communicate to a second NHRP-CRP server, said second NHRP-CRP being associated with said source node;

said second NHRP-CRP server forwarding said request to communicate to said first NHRP-CRP server through a routing procedure used by said connection-oriented network.

30. A method according to claim 29, wherein said forwarding step includes the step of said second NHRP-CRP server broadcasting said request to communicate to other NHRP-CRP servers existing on said connection-oriented network.

31. A method according to claim 29, further including the steps of:

maintaining a list of existing virtual channels within said connection-oriented network;

checking said connection-oriented address of said network spanning node and a connection-oriented address of said source node against said list of existing virtual channels;

after said checking step, deciding whether said list contains a first entry corresponding to said first virtual channel;

if said list does not contain said first entry, said NHRP-CRP server initiating a third-party connection set-up to establish said first virtual channel; and

releasing said first virtual channel after a predetermined period of inactivity of said first virtual channel.

32. A method of communicating connectionless datagrams between a source node and a destination node, said source node and said destination node residing on a connectionless network, said connectionless network overlaying a connection-oriented network and a connectionless subnetwork, said destination node residing on said connectionless subnetwork, said source node having a first network prefix, said destination node having a second network prefix, said method comprising the steps of:

establishing a first virtual channel between said source node and a network spanning node selected from the group consisting of a bridge and a router, said network spanning node having a first interface on said connection-oriented network, said network spanning node having a second interface on said connectionless subnetwork;

after said establishing step, sending a netmask from said network spanning node to said source node, said netmask including all connectionless addresses on said subnetwork reachable through said network spanning node;

after said sending step, communicating said connectionless datagrams from said source node to said network spanning node through said first virtual channel; and

relaying said connectionless datagrams from said network spanning node to said destination node.

33. A method of communicating connectionless datagrams between a source node and a destination node, said source node and said destination node residing on a connectionless network, said connectionless network overlaying a connection-oriented network, said connection-oriented network having a first connection-oriented subnetwork and a second connection-oriented subnetwork, said first connection-oriented subnetwork having a first gateway Next Hop Resolution Protocol-Connection Request Protocol (NHRP-CRP) server, said second connection-oriented subnetwork having a second gateway NHRP-CRP server, said source node residing on said first connection-oriented subnetwork, said destination node residing on said second connection-oriented subnetwork, said method comprising the steps of:

storing a connectionless-to-connection-oriented address mapping of said destination node with a predetermined NHRP-CRP server of said second connection-oriented subnetwork;

sending a request to communicate from said source node to a predetermined NHRP-CRP server of said first connection-oriented subnetwork, said request to communicate including a connectionless address of said destination node;

forwarding said request to communicate from said predetermined NHRP-CRP server of said first connection-oriented subnetwork to said second gateway NHRP-CRP server using a routing procedure;

resolving said connectionless address of said destination node into its connection-oriented address on said second connection-oriented subnetwork;

transmitting from said predetermined NHRP-CRP server of said second connection-oriented subnetwork to said source node a first virtual channel identifier of a first virtual channel between said source node and said destination node; and

said source node transmitting data frames to the destination node on said first virtual channel.

34. A method according to claim 33, wherein said forwarding step includes the steps of:

if said predetermined NHRP-CRP server on said first connection-oriented subnetwork is not the same device as said first gateway NHRP-CRP server, sending said request to communicate to said first gateway NHRP-CRP server;

relaying said request to communicate from said first gateway NHRP-CRP server to said second gateway NHRP-CRP server using said routing procedure.

35. A method according to claim 33, wherein said forwarding step includes the step of sending said request to communicate from said predetermined NHRP-CRP server of said first connection-oriented subnetwork directly to a gateway NHRP-CRP server, other than said first gateway NHRP-CRP server, existing on said connectionless network.