Method and apparatus for discovering server applications by a client application in a network of computer systems

• US 6,101,528 A
• Filed: 11/28/1997
• Issued: 08/08/2000
• Est. Priority Date: 03/27/1996
• Status: Expired due to Term

• Current Assignee: Intel Corporation
• Original Assignee: Intel Corporation
• Inventors: Butt, Alan
• Primary Examiner(s): An, Meng-Ai T.
• Assistant Examiner(s): PATEL, GAUTAM
• Application Number:
  US08/978,997
• Time in Patent Office: 984 Days
• Field of Search: 709/203, 709/229, 709/235, 709/245
• US Class Current: 709/203
• CPC Class Codes: H04L 67/06 specially adapted for file transfer, e.g. file transfer protocol [FTP]
• CPC Class Codes: H04L 67/34 involving the movement of software or configuration parameters network booting or remote initial program loading [RIPL] G06F9/4416
• CPC Class Codes: H04L 69/08 Protocols for interworking; Protocol conversion
• CPC Class Codes: H04L 69/329 in the application layer [OSI layer 7]
• CPC Class Codes: H04L 9/40 Network security protocols

Abstract

In a network of computer systems, each node having client applications that perform server application discovery is provided with a client discovery service having a first collection of functions, including a first registration function for registering discovery callback procedures of client applications, and a send function for sending discovery packets on behalf of the client applications. Additionally, each node having server applications that are interested in being discovered by client applications is provided with a server discovery service having a second collection of functions, including a second registration function for registering server applications interested in being discovered, and a respond function for sending discovery response packets on behalf of the registered server applications. During operation, these functions facilitate the client applications in performing server application discovery in a manner that reduces network traffics.

Claims

1. A computer system comprising an independent client discovery service including a send discovery packet service that broadcasts discovery packets on demand to other computer systems interconnected with the computer system, on behalf and at the request of a client application of the computer system, to facilitate discovery by the client application as to whether a server application that is of interest to the client application is available on at least one of the other computer systems, wherein the independent client discovery service maintains an exception list for subsequent communications of discovery packets, the exception list including indications of nodes that responded to previously sent discovery packets, and further wherein re-sent discovery packets are not sent to nodes included in the exception list.

2. The computer system as set forth in claim 1, wherein each discovery packet further comprises a datagram size denoting the maximum datagram size to be used for a discovery response packet, to allow the client discovery service to employ a buffer with a buffer size that is smaller than a transport datagram size of a transport protocol employed to broadcast the discovery packet to receive the discovery response packet.

3. The computer system as set forth in claim 1, wherein the exception list includes a list of client applications, containing identification information of computer systems that should not reply to the discovery packet, the identified computer systems being previously replied computer systems.

4. The computer system as set forth in claim 3, wherein the client discovery service further includes an update exception list service that updates the exception list of the client application with the identification information of the previously replied computer systems.

5. The computer system as set forth in claim 1, wherein the discovery service further includes a discovery scan service that repeatedly invokes the send discovery packet service to broadcast discovery packets with the reply traffic reduction information to perform a series of discoveries for the client application without overloading the interconnections between the computer systems.

6. A computer system comprising an independent server discovery service including a respond service that listens for discovery packets broadcast on demand from other computer systems interconnected to the computer system, and replies to appropriate ones of the detected discovery packets with discovery response packets on behalf of a server application of the computer system interested in being discovered by client applications of the other computer systems, wherein the independent server discovery service replies to discovery packets having exception lists in which the computer system is not listed.

7. The computer system as set forth in claim 6, wherein the computer systems comprises a plurality of server applications interested in being discovered by client applications of the other computer systems, and the respond service listens for the discovery packets for all server applications at a common socket or port.

8. The computer system as set forth in claim 6 wherein, each discovery response packet further comprises a datagram size denoting the maximum datagram size to be used for subsequent communication with the server application.

9. The computer system as set forth in claim 8 wherein the discovery response packet further includes application specific data specific to the server application, an offset identifying a starting location for the application specific data, and a data size parameter specifying the size of the application specific data.

10. The computer system as set forth in claim 6, wherein each discovery packet includes an exception list of a client application on whose behalf the discovery packet is being sent, the exception list containing identification information of computer systems that should not reply to the discovery packet, the identified computer systems being previously responded computer systems.

11. A network of computer systems comprising:

(a) a client system having a client discovery service including a first registration service to register a notification mechanism of a client application of the client system, the client system further having a send discovery packet service to send discovery packets to a server system interconnected with the client system on demand, on behalf and at the request of the registered client application, wherein the client discovery service facilitates discovery of whether a server application that is of interest to the registered client application is available on the server system independent of the server application'"'"'s knowledge of the client application; and

(b) the server system, including a server discovery service having a second registration service to register a notification mechanism of the server application, wherein the registered server application is available to interested client applications of the client system, including client applications that the server application has no knowledge of, and a respond service to listen for discovery packets from the client discovery service(s) of the client system, and to reply to the detected discovery packets with discovery response packets on behalf of the registered server application, as appropriate.

12. The network of computer systems as set forth in claim 11, wherein each discovery packet comprises a datagram size denoting the maximum datagram size to be used for a discovery responsive packet, to allow the client discovery service of the first computer system to use a buffer with a buffer size smaller than a transport datagram size of a transport protocol employed to send the discovery packet to receive the discovery response packet.

13. The network of computer systems as set forth in claim 11, wherein the second computer includes a plurality of server applications interested to be discovered by client applications of the first computer system including client applications that the server applications have no knowledge of, and the respond function listens for the discovery packets for all server applications at a common socket or port.

14. The network of computer systems as set forth in claim 11 wherein each discovery response packet comprises a datagram size denoting the maximum datagram size to be used for subsequent communication with the server application.

15. The network of computer systems as set forth in claim 14 wherein the discovery response packet further includes application specific data specific to the server application, an offset identifying a starting location for the application specific data, and a data size parameter specifying the size of the application specific data.

16. The network of computer systems as set forth in claim 11, wherein the send discovery packet service of the independent client discovery service of the first computer system broadcasts each discovery packet to all computer systems interconnected with the first computer system, including the second computer system, including in each broadcast discovery packet information that facilitates reduction in reply traffic resulting from the broadcast by eliminating unnecessary cumulative replies.

17. The network of computer systems as set forth in claim 16, wherein the client discovery service of the first computer system further includes a discovery scan service that repeatedly invokes the send discovery packet service to broadcast discovery packets with the reply traffic reduction instructions to perform a series of discoveries for the client application without overloading the interconnections between the computer systems.

18. The network of computer systems as set forth in claim 16, wherein each discovery packet includes an exception list of the client application containing identification information of computer systems that should not reply to the discovery packet, the identified computer systems being previously replied computer systems.

19. The network of computer systems as set forth in claim 18, wherein the client discovery service of the first computer system further includes an update exception list service that updates the exception list of the client application with identification information of the previously responded computer systems.

20. The network of computer systems as set forth in claim 11, wherein the client discovery service of the first computer system further includes a discovery scan service that repeatedly invokes the send discovery packet service in a selected one of a plurality of manners to send discovery packets to a plurality of computer systems interconnected with the first computer system, including the second computer system, to perform a series of discoveries for the client application.

21. The network of computer systems as set forth in claim 20, wherein the plurality of manners of repeated invocations of the send discovery packet service of the client discovery service of the first computer system include a first manner where the send discovery packet service is repeatedly invoked to build and send discovery packets to a first list of other computer systems including the second computer system, these other computer systems being included in the first list based on the client application'"'"'s interest independent of whether these computer systems having previously responded or not, and a second manner where the send discovery packet service is repeatedly invoked to build and send discovery packets to a second list of other computer systems including the second computer system, these other computer systems being included in the second list based on the client application'"'"'s interest and that these other computer systems having previously responded.

22. The network of computer systems as set forth in claim 21, wherein the client discovery service of the first computer system further includes a build address structure service that builds a current address structure for a computer system of either the first or the second list of other computer systems, the current address structure containing information for communicating with the particular computer system.

23. In a network of computer systems, a computer implemented method for discovering a server application by a client application independent of the server application'"'"'s knowledge, if any, of the client application, the method comprising:

a) the client application independently registering its notification mechanism with an independent client discovery service;

b) the independent client discovery service sending a discovery packet on demand, on behalf and at the request of the client application;

c) the server application independently registering its notification mechanism with an independent server discovery service;

d) the server discovery service listening for the discovery packet, and replying with a discovery response packet on behalf of the server application, independent of the server application'"'"'s knowledge, if any, of the client application; and

e) the client discovery service by way of the registered notification mechanism of the client application notifying the client application of the receipt of the discovery response packet.

24. The method as set forth in claim 23, wherein (b) comprises the client discovery service sending a discovery packet to each of a plurality of computer systems, one computer systems at a time, waiting at least a predetermined amount of time between packets to avoid overloading the network.

25. The method as set forth in claim 24, wherein (b) is performed for previously responded computer systems only.

26. The method as set forth in claim 23, wherein (b) comprises the client discovery service repeatedly broadcast discovery packets, with each discovery packet including information that facilitates reduction in reply traffic resulting from the broadcast by eliminating unnecessary cumulative replies.

27. The method as set forth in claim 23, wherein the server discovery service services a plurality of server applications, and (d) comprises the server discovery service listening for discovery packets for all server applications at a common socket or port.

28. The method as set forth in claim 23, wherein the method further comprises (f) the registered notification mechanism of the client application updating a list with computer systems having responded to discovery packets previously sent.

29. The method as set forth in claim 23, wherein the method further comprises (f) the registered notification mechanism of the client application updating a list identifying computer systems that should not reply to future discovery packets that are broadcast.

30. The method as set forth in claim 23, wherein (b) comprises the client discovery service broadcasting each discovery packet with information that facilitates reduction in reply traffic resulting from the broadcast by eliminating unnecessary cumulative replies.

31. A computer system comprising an independent client discovery service including a send discovery packet service for building and sending a discovery packet on demand to another computer system interconnected with the computer system, on behalf and at the request of a client application of the computer system, to allow the client application to discover as to whether a server application that is of interest to the client application is available on the other computer system, and a discovery scan service for repeatedly invoking the send discovery packet service in a selected one of a plurality of manners to perform a series of discoveries for the client application, wherein the independent client discovery service maintains an exception list for subsequent communications of the discovery packets, the exception list including indications of nodes that responded to previously sent discovery packets, and further wherein re-sent discovery packets are not sent to nodes included in the exception list.

32. The computer system as set forth in claim 31 wherein the plurality of manners include a first manner where the send discovery packet service is repeatedly invoked to build and send discovery packets to a first list of other computer systems, these other computer systems being included in the first list based on the client application'"'"'s interest independent of whether these computer systems having previously responded or not, and a second manner where the send discovery packet service is repeatedly invoked to build and send discovery packets to a second list of other computer systems, these other computer systems being included in the second list based on the client application'"'"'s interest and that these other computer systems having previously responded.

33. A network medium having sequences of instructions stored therein, which when executed cause a client application of a client computer to discover a server application of a server computer by performing:

a) the client application independently registering its notification mechanism with a client discovery service on the client computer;

b) the client discovery service sending a discovery packet on demand, on behalf and at the request of the registered client application over the network;

c) the server application independently registering its notification mechanism with a server discovery service on the server computer;

d) the server discovery service listening for the discovery packet over the network, and replying with a discovery response packet on behalf of the registered server application, as appropriate, independent of the server application'"'"'s knowledge of the client application; and

e) the client discovery service by way of the registered notification mechanism of the client application notifying the registered client application of the receipt of the discovery response packet.

34. The network medium set forth in claim 33, wherein (b) comprises the client discovery service sending a discovery packet to each of a plurality of computer systems over the network, one computer system at a time, waiting at least a predetermined amount of time between packets to avoid overloading the network.

35. The network medium set forth in claim 34, wherein (b) is performed for previously responded computer systems only.

36. The network medium set forth in claim 33, wherein (b) comprises the client discovery service repeatedly broadcasting discovery packets, with each discovery packet including information that facilitates reduction in reply traffic resulting from the broadcast by eliminating unnecessary cumulative replies.

37. The network medium set forth in claim 33, wherein the server discovery service services a plurality of server applications, and (d) comprises the server discovery service listening for discovery packets for all server applications at a common socket or port.

38. The network medium set forth in claim 33, further comprising (f) the registered notification mechanism of the client application updating a list with computer systems having responded to discovery packets previously sent.

39. The network medium set forth in claim 33, further comprising (f) the registered notification mechanism of the client application updating a list identifying computer systems that should not reply to future discovery packets that are broadcast.

40. The network medium set forth in claim 33, wherein (b) comprises the client discovery service broadcasting each discovery packet with information that facilitates reduction in reply traffic resulting from the broadcast by eliminating unnecessary cumulative replies.