Virtual transport layer interface and messaging subsystem for high-speed communications between heterogeneous computer systems

• US 6,233,619 B1
• Filed: 07/31/1998
• Issued: 05/15/2001
• Est. Priority Date: 07/31/1998
• Status: Expired due to Term

• Current Assignee: Unisys Corporation
• Original Assignee: Unisys Corporation
• Inventors: Salamon, Gary, Narisi, Anthony, Kain, Michael T., Coyne, Lois B., Jennion, Susan
• Primary Examiner(s): VU, VIET DUY
• Application Number:
  US09/126,920
• Time in Patent Office: 1,019 Days
• Field of Search: 709/217, 709/227, 709/228, 709/230, 709/236, 709/237, 709/238, 709/245, 709/246, 709/250, 709/319, 709/320, 709/321, 709/328, 709/329
• US Class Current: 709/230
• CPC Class Codes: H04L 69/32 Architecture of open systems interconnection [OSI] 7-layer type protocol stacks, e.g. the interfaces between the data link level and the physical level
• CPC Class Codes: H04L 69/325 in the network layer [OSI layer 3], e.g. X.25 H04L69/16 takes precedence
• CPC Class Codes: H04L 69/326 in the transport layer [OSI layer 4] H04L69/16 takes precedence
• CPC Class Codes: H04L 9/40 Network security protocols

Abstract

Methods and apparatus that enable network applications executing on respective directly interconnected computer systems to communicate at high speed, with low latency, over the interconnection therebetween such that both systems may use their native mechanisms to communicate with each other without change in those mechanisms, rather than over conventional network communication paths such as Ethernet. Communication between applications in co-resident, closely coupled processing environments is provided by replacing the conventional TCP transport layer and the conventional IP network layer with a reliable messaging subsystem (“MSS”) for data transfers between the closely coupled systems which provides an interface which is independent of the communication protocol of the interconnect and a virtual transport layer (“VTL”) which simulates a known transport layer protocol, such as TCP/IP, to the network applications. MSS is a system interconnect independent messaging transport which presents to its users many different delivery and notification mechanisms for the transfer of both control and data information between different heterogeneous environments, while VTL uses the MSS connection to provide a consistent, interconnect independent interface to the session layer.

Claims

1. Apparatus which enables a first network application, executing on a first computer system, and a second network application, executing on a second computer system which is directly interconnected and closely coupled to the first computer system, to communicate with each other without affecting the first and second network applications, said first and second computer systems being heterogeneous, said apparatus comprising:

an interconnection coupling an input/output (I/O) subsystem of the first computer system to an I/O subsystem of the second computer system and over which data can be transmitted between the first and second computer systems independent of a network interface card; and

an interconnection messaging system executing on the first and second computer systems that provides general purpose transport interfaces and that simulates a predetermined transport layer protocol to the first and second network applications whereby said first and second network applications may communicate in a manner which is transparent to the first and second network applications.

2. The apparatus as in claim 1, wherein the interconnection between the I/O subsystem of the first computer system and the I/O subsystem of the second computer system comprises a physical connection between the I/O subsystems over which data can be transmitted.

3. The apparatus as in claim 1, wherein the interconnection messaging system includes a messaging subsystem (“

MSS”

) which provides said general purpose transport interfaces, said general purpose transport interfaces being independent of communication protocols of the interconnection, and which provides further interfaces on either end of the interconnection which are dependent on the communication protocols of the interconnection, whereby only the further interfaces must be changed when the interconnection is changed.

4. Apparatus as in claim 3, wherein the MSS includes an MSS component on each of said first and second computer systems, each MSS component having at least one local MSS user connected thereto through said independent transport interface, an MSS component on the first computer system creating a dialog to each complementary remote MSS user of the second computer system.

5. Apparatus as in claim 4, wherein each MSS component includes means for building dialog tables for local MSS users informing the local MSS users about any complementary remote MSS users accessible via the interconnection and for updating said dialog tables as complementary remote MSS users are added or removed.

6. Apparatus as in claim 4, wherein each MSS component includes means for performing dialog management functions which allow the local MSS users to establish, receive status about, and destroy dialogs with the complementary remote MSS users over the interconnection.

7. Apparatus as in claim 4, wherein each MSS component includes means for performing control message functions which allow the local MSS users and the complementary remote MSS users to pass control messages to each other in a manner which is independent of the communication protocols of the interconnection.

8. Apparatus as in claim 4, wherein each MSS component includes means for transferring data between local and complementary remote MSS users over data dialogs established between said local and remote MSS users.

9. Apparatus as in claim 4, wherein one of said local and one of said complementary remote MSS users are complementary virtual transport layer (“

VTL”

) components which simulate said predetermined transport layer protocol so that the first and second network applications may communicate with each other over the interconnection in a manner which is transparent to the first and second applications.

10. The apparatus of claim 9, wherein said complementary VTL components provide transport dialog establishment, data transfer, and transport dialog termination between said first and second computer systems using the MSS.

11. Apparatus as in claim 9, wherein said VTL components respectively interface with said first and second network applications, and said VTL components are implemented on the first and second computer systems as complementary MSS users which are connected to the MSS through the independent transport interfaces of the MSS.

12. Apparatus as in claim 11, wherein each MSS component includes means for performing control message functions which allow the local VTL component and the complementary remote VTL component to create a reliable control dialog over which the complementary VTL components may exchange message sequences to coordinate creating and opening dialogs.

13. Apparatus as in claim 12, wherein when data is to be transferred from said first network application to said second network application over said interconnection, said VTL component interfaced to said first network application appends a VTL data transfer header to data to be transferred to said second network application and initiates a data transfer over said open dialog.

14. A method for enabling a first network application, executing on a first computer system, and a second network application, executing on a second computer system which is directly interconnected and closely coupled to the first computer system via an interconnection between an input/output (I/O) subsystem of the first computer system and an I/O subsystem of the second computer system to transmit data therebetween independent of a network interface card and in the native protocols of the first and second network applications, comprising the steps of:

simulating a predetermined transport layer protocol to the first and second network applications on the respective first and second computer systems;

creating a dialog over the interconnection through which the first and second network applications may communicate in a manner which is transparent to the first and second network applications;

opening the dialog for data transfer between the first and second network applications;

applying to the data to be transferred a data transfer header; and

transferring the data and the data transfer header over the interconnection via the open dialog.

15. The method of claim 14, comprising the additional steps of creating a plurality of dialogs over the interconnection for a plurality of pairs of said first and second applications whereby the applications in each pair may communicate in a manner which is transparent to the native protocols of the first and second applications in the pair, and specifying the dialog which is to be used for the data transfer between the applications in the pair.