Electrical computers and digital processing systems: multicomput – Computer-to-computer protocol implementing
Reexamination Certificate
2000-10-17
2004-07-06
Harvey, Jack B. (Department: 2144)
Electrical computers and digital processing systems: multicomput
Computer-to-computer protocol implementing
C709S223000, C709S227000, C707S793000
Reexamination Certificate
active
06760771
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Technical Field
The present invention relates to computer networks, and more particularly to a method and system in an Internet Protocol (IP) network for optimally dispatching IP telnet datagram traffic among multiple TN3270 Servers.
2. Description of the Related Art
SNA and IP Environment
Companies are increasingly interested in consolidating the multiple specialized networks that they operate or lease from service providers onto a single protocol network. These multiple specialized networks operate on diverse networking technologies such as Systems Network Architecture (SNA), Internet Protocol (IP) or Internetwork Packet Exchange (IPX). In making consolidation one of their top priorities, companies are almost exclusively selecting IP as their protocol of choice. For the overwhelming majority of these companies that are using SNA protocols and applications, however, there remains the need to maintain the ability to access the enormous quantity of existing corporate data that resides in traditional mainframes and only accessible through SNA applications.
Internet
The Internet is a global network of computers and computers networks (the “Net”). The Internet connects computers that use a variety of different operating systems or languages, including UNIX, DOS, Windows, Macintosh, and others. To facilitate and allow the communication among these various systems and languages, the Internet uses a language referred to as TCP/IP (“Transmission Control Protocol/Internet Protocol”). TCP/IP protocol supports three basic applications on the Internet:
(1) transmitting and receiving electronic mail,
(2) logging into remote computers (the “Telnet”), and
(3) transferring files and programs from one computer to another (“FTP” or “File Transfer Protocol”).
TCP/IP
The Transmission Control Protocol/Internet Protocol (TCP/IP) protocol suite is used to establish an interconnection of networks that provide universal communication services: an internetwork, or internet. Each physical network has its own technology dependent communication interface (in the form of a programming interface) that provides basic communication functions between the physical network and the user applications. The architecture of the physical networks is hidden from the user. TCP/IP also provides interconnection between different physical networks to form what appears to the user to be one large network.
TCP is a transport layer protocol providing end-to-end data transfer and is responsible for providing a reliable exchange of information between networked computer systems. Multiple applications can be supported simultaneously over one TCP connection between two computer systems.
IP is an inter-network layer protocol hiding the physical network architecture bellow it. Part of the communicating messages between computers is a routing function that ensures that messages will be correctly directed within the network to be delivered to their destination. IP provides this routing function. An IP message is called an IP datagram.
Application Level protocols are utilized in addition to TCP/IP to transfer user and application data from a computer system to a destination computer system. Examples of such Application Level protocols include File Transfer Protocol (FTP), Telnet, Gopher, Hyper Text Transfer Protocol (HTTP).
IP Router
A “router” is a computer that interconnects two networks and forwards messages from one network to the other. Routers select the best transmission path between networks utilizing the IP layer of the TCP/IP protocol stack, such that any host (or computer) or workstation running TCP/IP over more than one interface could, in theory, forward messages between networks. Because IP implements basic routing functions, the term “IP router” is often used. However, dedicated network hardware routers can provide more sophisticated routing functions than the minimum functions implemented in IP.
World Wide Web
With the increasing size and complexity of the Internet, tools that are often called navigators or navigation systems have been developed to help find information on the network. Navigation systems include standards such as Archie, Gopher and, most well-known, the World Wide Web (“WWW” or “the Web”). In addition to serving as an Internet-based navigation system, the Web is also an information distribution and management system for the Internet. The Web provides an end user with a seamlessly integrated format of information, including still images, text, audio and video. A user on the Web using a graphical user interface may transparently communicate with different host computers on the system, different system applications, and different information formats for files and documents including text, sound, and graphics.
Telnet 3270
In an IP environment, telnet technologies (TN3270) is widely utilized to transport SNA information across an IP network. This technique for SNA “green screen” workstation users employs a Client/Server approach. IBM's “Host On Demand” or “WebClient” by CISCO are examples of client software implementations. Network Utility from IBM or CISCO router's offerings are typical Server implementations (hardware and software). The “TN3270 client” component usually runs within the customer's workstation while the “TN3270 server.” component is usually placed in front of the customer's Data Center mainframes (or sometimes directly within the mainframe itself) or within the customer's branch offices. As illustrated in
FIG. 1
, IP protocols are used between a TN3270 server (
102
) and TN3270 clients (
101
), while traditional SNA protocols are used between TN3270 server (
102
) and target SNA Applications (
103
). The TN3270 client usually runs on an end user workstation.
Telnet 3270 Device Type
The characteristics of TN3270 data exchanged between TN3270 client and SNA application, depend on both the device on which the TN3270 client is located, and the SNA application. For instance, a device which is only capable of displaying information retrieved from the SNA application, is not capable of processing TN3270 print data. The characteristics of TN3270 data are partly identified by the Device Type (DEVICE-TYPE) parameter negotiated between the TN3270 client and the TN3270 server when the TN3270 connection is established. The possible values of this DEVICE-TYPE parameter are defined in the extension of the TN3270 protocol (TN3270E) described in the Request For Comments (RFCs) 2355, “TN3270 Enhancements” of the Internet Engineering Task Force (IETF). Typically, the DEVICE-TYPE indicates if the device is a display terminal or a printer.
Dispatcher System
When multiple TN3270 servers are used to gain access to SNA applications located within a SNA network, a dedicated device called a “dispatcher system” is often used within the TCP/IP network for dispatching the traffic to these multiple TN3270 servers. The main goal of the dispatcher system is to balance the load across the multiple TN3270. For instance, when a very powerful TN3270 server and a smaller TN3270 server are available, more traffic should be dispatched on the very powerful TN3270 server than on the smaller one. Such dispatcher systems are either dedicated hardware devices, or software components installed on existing network devices such as IP routers.
More detailed explanations of telnet, TN3270, and Network Utility, can be found in the following publications incorporated herewith by reference:
“TCP/IP Tutorial and Technical Overview” by Martin W. Murhammer, Orcun Atakan, Stefan Bretz, Larry R. Pugh, Kazunari Suzuki, David H. Wood, International Technical Support Organization, October 1998, GG24-3376-05.
“Internet in a nutshell” by Valerie Quercia, published by O'Reilly, October 1997.
“IBM 2216/Network Utility Host Channel Connection”, Erol Lengerli, Jacinta Carbonell, Thomas Grueter; IBM International Technical Support Organization, January 1999, SG24-5303-00.
“IBM Network Utility Description and Configuration Scenarios”, Tim Kearby, Peter Gayek, Gallus Schlegel, Imre Szabo, Zhi-Yon
Giroir Didier
Hericourt Olivier
Dillon & Yudell LLP
Harvey Jack B.
Phan Tam T.
Pivnichny John R.
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