Method and apparatus for detecting switched network protocols

• US 6,122,287 A
• Filed: 02/09/1996
• Issued: 09/19/2000
• Est. Priority Date: 02/09/1996
• Status: Expired due to Term

• Current Assignee: Hewlett Packard Enterprise Development LP (Hewlett-Packard Enterprise Company)
• Original Assignee: Microcom Systems Incorporated
• Inventors: Schubert, Joachim, Lobbert, Achim, Ohanian, Russ, Steinka, Bradford R.
• Primary Examiner(s): Nguyen, Chau
• Assistant Examiner(s): LEE, CHI HO A
• Application Number:
  US08/599,183
• Time in Patent Office: 1,684 Days
• Field of Search: 375/222, 370/465, 370/466, 370/467, 370/469, 370/470, 370/471, 370/472, 370/475, 370/476, 370/276, 370/419, 370/421, 370/522, 370/524, 395/821, 395/836, 395/200.6, 395/200.61, 395/200.62, 395/200.63, 395/200.64, 395/8.31, 395/285, 379/210, 379/93.31-93.34, 379/93.08, 379/100.17
• US Class Current: 370/465
• CPC Class Codes: H04L 69/18 Multiprotocol handlers, e.g. single devices capable of handling multiple protocols
• CPC Class Codes: H04L 9/40 Network security protocols

Abstract

In order to transfer data via a switched network that provides a wide range of network services, the users must establish a circuit or network connection and establish a data link connection. The circuit or network connection provides the physical connection between the users and data link connection provides the protocols and procedures for the transfer of data. Because the network provides a wide range of services, the users, typically by prior agreement, designate a common data link protocol to facilitate the transfer of data. A data link connection will not be established if the users are not using the same data link protocol. A method and apparatus are disclosed which permit a local system to detect the data link protocol used by a remote system. The invention provides a method for detecting the data link protocol used by the remote system when the remote system initiates the data link setup and a method for detecting the data link protocol when the local system initiates the data link setup.

Claims

1. A network interfacing apparatus for interfacing at least one unit of terminal equipment to a switched network having at least one channel for receiving information including data from a remote site in accordance with either one of at least two distinct and predefined protocols, wherein each of said predefined protocols is identified by at least one predefined characteristic data value uniquely positioned within a predetermined sequence of values within a unit of information, said apparatus comprising:

receiving means for receiving at least one unit of information from said channel;

at least two protocol system means, one for each of said predefined protocols, for enabling said apparatus to communicate over said channel with said remote site according to a select one of said predefined protocols;

comparing means for respectively comparing at least one characteristic data value of said at least one unit of information received by said receiving means with at least one predefined characteristic data value used to identify said predefined protocols so as to identify the predefined protocol of the unit of information received by said receiving means; and

means for selecting and enabling the appropriate one of said protocol system means in response to a match between the at least one characteristic data value of said at least one unit of information and the at least one predefined characteristic data value used to identify said predefined protocols, so as to permit said apparatus to communicate over said channel with the remote site according to the selected one of said predefined protocols.

2. A network interfacing apparatus according to claim 1, further comprising

at least a third protocol system means for enabling said apparatus to communicate with said remote site according to a third protocol of said predefined of protocols.

3. A network interfacing apparatus according to claim 1, further comprising:

at least a third protocol system means for enabling said apparatus to communicate over said channel with said remote site according to a third protocol of said predefined of protocols;

means for selecting and enabling the third protocol system means in response to a match between the at least one characteristic data value of said at least one unit of information and the at least one predefined characteristic data value used to identify said predefined protocols, so as to permit said apparatus to communicate over said channel with the remote site according to the selected one of said predefined protocols.

4. A network apparatus according to claim 1, wherein each of said predefined protocols is a data link protocol for the transfer of data across a switched network.

5. A network apparatus according to claim 1, wherein each of said predefined protocols is a data link protocol for the transfer of data across an ISDN network.

6. A network apparatus according to claim 1, wherein said at least one characteristic data value is defined within at least one data field in said at least one unit of information;

and

wherein said comparing means includes means for respectively comparing the data values within the at least one data field within at least one unit of information received by said receiving means with at least one of the corresponding predefined characteristic data values used to identify said predefined protocols.

7. A network apparatus according to claim 1, further comprising

at least a third protocol system means for enabling said apparatus to communicate over said channel with said remote site according to a third protocol of said predefined of protocols;

and

a default protocol selection and enabling means for selecting and enabling the third protocol system means when said comparing means is unable to match any of the at least one characteristic data values of said at least one unit of information received by said receiving means with the at least one predefined characteristic data values used to identify said predefined protocols.

8. A method of detecting any one of a selected number of predefined communication protocols, each of said protocols being used to communicate information over a switched network having at least one channel for transmitting information and being identified by at least one characteristic data value within a predetermined sequence of values within a unit of information, said method comprising the steps of:

receiving at least one unit of information from said channel;

comparing at least one characteristic data value of said at least one unit of information received with at least one predefined characteristic data value used to identify said predefined protocols so as to identify the predefined protocol identified in the unit of information received from said channel; and

selecting and enabling a protocol system means for transmitting information over said channel in accordance with a particular protocol in response to a match between the at least one characteristic data value of said at least one unit of information and the at least one predefined characteristic value used to identify each of said predefined protocols, so as to permit communication over said channel with the remote site according to the selected one of said predefined protocols.

9. The method according to claim 8, wherein the step of selecting and enabling includes the step of

selecting and enabling a default protocol system means for transmitting information over said channel in accordance with the default one of said protocols when the at least one characteristic data values of said at least one unit of information fails to match, during said step of comparing, with the any of the at least one predefined characteristic data values used to identify said predefined protocols.

10. The method according to claim 8, wherein each of said predefined communication protocol is a data link layer protocol.

11. A network interfacing apparatus for interfacing at least one unit of terminal equipment to a switched network having at least one channel for transferring information including data to and from a remote system in accordance with any one of at least two predefined protocols, said apparatus comprising:

communication means for transmitting and receiving units of information via said channel;

at least two protocol system means, one for each of said predefined protocols, for enabling said apparatus to communicate via said channel with said remote system according to any one of said predefined protocols;

controller means for controlling said communication means, said controller means including means for selecting a first protocol system means to attempt to establish a data link connection between said apparatus and said remote system according to said first protocol, and means for selecting and enabling said first protocol system means if said data link connection is established and means for selecting and establishing said second protocol means if said data link connection according to said first protocol cannot be established.

12. A network interfacing apparatus for interfacing at least one unit of terminal equipment to a switched network having at least one channel for transferring information including data to and from a remote system in accordance with one of a plurality of predefined protocols, said apparatus comprising:

communication means for transmitting and receiving units of information via said channel,

at least a first protocol system means for enabling said apparatus to communicate via said channel with said remote system according to a first protocol of said predefined protocols;

at least a second protocol system means for enabling said apparatus to communicate via said channel with said remote system according to a second protocol of said predefined protocols;

controller means for controlling said communication means, said controller means including means for selecting said first protocol system means to attempt to establish a data link connection via said channel between said apparatus and said remote system according to said first protocol, and means for selecting and enabling said first protocol system means to enable said apparatus to communicate via said channel with said remote system if said data link connection is established; and

means for selecting said second protocol means if said data link connection according to said first protocol cannot be established to attempt to establish a data link connection between said apparatus and said remote system according to said second protocol, means for waiting for a predefined time period for said data link connection according to said second protocol to be established and means for selecting and enabling said second protocol system means to enable said apparatus to communicate with said remote system if said data link connection is established.

13. A method of detecting a communication protocol of the type used to communicate with a remote system over a switched network having at least one channel for receiving information, said method comprising the steps of:

transmitting over said channel a data link setup command according to a first communication protocol to said remote system;

waiting for a predetermined time for said remote system to acknowledge said data link setup command; and

selecting and enabling a first protocol system means for providing communications over said channel according to said first communication protocol if said remote system acknowledges said data link setup command within said predefined time and selecting and enabling a second protocol system means for providing communications over said channel according to said second communication protocol if said remote system does not acknowledge said data link setup command within said predefined time.

14. A method of detecting a communication protocol of the type used to communicate with a remote system over a switched network having at least one channel for receiving information, said method comprising the steps of:

transmitting over said channel a data link setup command according to a first communication protocol to said remote system;

waiting for a predetermined time for said remote system to acknowledge said data link setup command;

selecting and enabling a first protocol system means for providing communications over said channel according to said first communication protocol if said remote system acknowledges said data link setup command within said predefined time; and

if said remote system does not acknowledge said data link setup command within said predefined time;

transmitting over said channel a second data link setup command according to a second communication protocol to said remote system;

waiting for a second predetermined time for said remote system to acknowledge said second data link setup command;

selecting and enabling a second protocol system means for providing communications over said channel according to said second communication protocol if said remote system acknowledges said second data link setup command within said second predefined time.

15. A network interfacing apparatus for interfacing at least one unit of terminal equipment to a switched network having at least one channel for receiving information including data from a remote site in accordance with either one of at least two distinct and predefined protocols, wherein each of said predefined protocols is identified by at least one predefined characteristic data value uniquely positioned within a predetermined sequence of values within a unit of information, said apparatus comprising:

a receiver adapted for receiving at least one unit of information from said channel;

at least two protocol system, one for each of said predefined protocols, adapted for enabling said apparatus to communicate over said channel with said remote site according to a select one of said predefined protocols;

a comparing element adapted for respectively comparing at least one characteristic data value of said at least one unit of information received by said receiver with at least one predefined characteristic data value used to identify said predefined protocols so as to identify the predefined protocol of the unit of information received by said receiver; and

a protocol selector adapted for selecting and enabling the appropriate one of said protocol systems in response to a match between the at least one characteristic data value of said at least one unit of information and the at least one predefined characteristic data value used to identify said protocol, so as to permit said apparatus to communicate over said channel with the remote site according to the selected one of said predefined protocols.

16. A network interfacing apparatus according to claim 15, further comprising

at least a third protocol system adapted for enabling said apparatus to communicate over said channel with said remote site according to a third protocol of said predefined of protocols.

17. A network interfacing apparatus according to claim 15, further comprising:

at least a third protocol system adapted for enabling said apparatus to communicate over said channel with said remote site according to a third protocol of said predefined of protocols; and

wherein said protocol selector is adapted for selecting and enabling the third protocol system in response to a match between the at least one characteristic data value of said at least one unit of information and the at least one predefined characteristic data value used to identify said predefined protocol, so as to permit said apparatus to communicate over said channel with the remote site according to the selected one of said predefined protocols.

18. A network apparatus according to claim 15, wherein each of said predefined protocols is a data link protocol for the transfer of data across a switched network.

19. A network apparatus according to claim 15, wherein each of said predefined protocols is a data link protocol for the transfer of data across an ISDN network.

20. A network apparatus according to claim 15, wherein said at least one characteristic data value includes at least one data field value in said at least one unit of information and

wherein said comparing element is adapted for comparing said data field value with a predefined corresponding value appropriate for at least one of said predefined protocols.

21. A network apparatus according to claim 15, further comprising

at least a third protocol system adapted for enabling said apparatus to communicate over said channel with said remote site according to a third protocol of said predefined of protocols;

and

a default protocol selector adapted for selecting and enabling the third protocol system corresponding to the one of said predefined protocols when said comparing element is unable to match any of the at least one data value of said at least one unit of information with at least one predefined characteristic data value used to identify said predefined protocols so as to identify the predefined protocol of the unit of information received by the receiver.

22. A network interfacing apparatus for interfacing at least one unit of terminal equipment to a switched network having at least one channel for transferring information including data to and from a remote system in accordance with any one of at least two predefined protocols, said apparatus comprising:

a network interface adapted for transmitting and receiving units of information via said channel;

at least two protocol systems, one for each of said predefined protocols, adapted for enabling said apparatus to communicate via said channel with said remote system according to any one of said predefined protocols; and

a system controller adapted for controlling said network interface, for selecting a first protocol system to attempt to establish a data link connection via said channel between said apparatus and said remote system according to said first protocol, and for selecting and enabling said first protocol system if said data link connection via said channel is established and for selecting and establishing said second protocol system if said data link connection via said channel according to said first protocol cannot be established.

23. A network interfacing apparatus for interfacing at least one unit of terminal equipment to a switched network having at least one channel for transferring information including data to and from a remote system in accordance with one of a plurality of predefined protocols, said apparatus comprising:

a network interface adapted for transmitting and receiving units of information via said channel,

at least a first protocol system adapted for enabling said apparatus to communicate via said channel with said remote system according to a first protocol of said predefined protocols;

at least a second protocol system adapted for enabling said apparatus to communicate via said channel with said remote system according to a second protocol of said predefined protocols;

a system controller adapted for controlling said network interface, for selecting said first protocol system to attempt to establish a data link connection between said apparatus and said remote system according to said first protocol, for waiting for a predefined time period for said data link connection according to said first protocol to be established and for selecting and enabling said first protocol system means to enable said apparatus to communicate via said channel with said remote system if said data link connection is established; and

for selecting said second protocol system if said data link connection via said channel according to said first protocol cannot be established to attempt to establish a data link connection between said apparatus and said remote system according to said second protocol, for waiting for a predefined time period for said data link connection according to said second protocol to be established and for selecting and enabling said second protocol system to enable said apparatus to communicate via said channel with said remote system if said data link connection is established.