This chapter presents an overview of the major features of the Silicon Graphics IRIS SNA SERVER, the base upon which all other IRIS SNA products are constructed. It describes the product components and the server's relationship to other IRIS SNA products. The chapter concludes with a discussion of IRIS Token Ring and IRIS SDLC network configurations.
 | Note: For more detailed information on product features and implemented IRIS SNA SERVER functions, see Appendix A of this guide. |
Figure 1-1 diagrams the relationship between the IRIS SNA SERVER and the other IRIS SNA products. The IRIS SNA Scheduler is the main background process of the IRIS SNA SERVER. It contains the Physical Unit (PU) 2.0 and
PU 2.1 support that provides network connectivity for the IRIS SNA 3270,
IRIS SNA 3770, and the IRIS SNA Logical Unit (LU) 6.2 products. The scheduler also contains device driver support for the Synchronous Data Link Control (SDLC) controller and token ring communications boards.
The IRIS SNA SERVER is a communications package that enables you to use the capabilities of the IBM Systems Network Architecture on IRIS-4D™ Series workstations. The server provides interprocess communication services within both host-terminal and peer-to-peer environments that are governed by specific rules, or protocols. The IRIS SNA SERVER supports IBM LU type 0, 1, 2, and 3 protocols that implement terminal-emulation software and SNA LU 6.2 protocols that manage communications between two programs. Transmission can be through the SDLC Wide Area Network (WAN) or the token ring Local Area Network (LAN).
The IRIS SNA SERVER contains a scheduler accessed by the Application Program Interface (API) provided in the IRIS SNA SERVER and the IRIS LU6.2 software. The API uses simple commands, called verbs, to exchange data, transmit requests, and receive replies.
Configuration and operation of the server is accomplished through the
X Window™ and Motif™- based network management tool IRIS SNAView, which provides an alternative to the VT100-based interface of previous releases. IRIS SNAView facilitates configuring and operating the IRIS SNA SERVER and managing IRIS SNA LU 6.2 sessions. The main window of this graphical user interface serves as the central information and operations panel. All of the pertinent information needed to configure and use the IRIS SNA SERVER is accessible through this window and its secondary windows and related dialog boxes.
| Note: Developers and users who do not have Silicon Graphics terminals can still use the VT100 user interface programs. Refer to the IRIS SNA SERVER VT100 Interface Guide. |
The IRIS SNA SERVER software product includes the Application Program Interface, or API, which makes the services in SNA LU types 0, 1, 2, or 3 available to the user program. It also provides configuration and network management support for these optional SNA products from Silicon Graphics:
IRIS SNA 3270
The IRIS SNA 3270 emulator software provides end users of IRIS workstations and servers an easy-to-use, full screen, 3270 Emulator for accessing IBM host-based 3270 applications. The IRIS SNA 3270 emulator software allows the IRIS workstation or server to emulate an IBM 3278 or 3179 Model 2, 3, 4, or 5 terminal with extended attributed support. The software can be configured to emulate a control unit terminal with a single host session, or a distributed function terminal with up to five simultaneous host sessions. The IRIS SNA 3270 emulator software supports the IBM IND$FILE file transfer program designed for micro to mainframe communications. It also supports Silicon Graphics proprietary high-speed file transfer package, SGIXFR, for both the VM and MVS IBM host operating systems.IRIS SNA LU 6.2
The IRIS SNA LU 6.2 is a powerful programming tool that allows end users to realize the power of distributed processing in an IBM SNA network. The IRIS SNA LU 6.2 emulator software provides the IRIS workstation or server with the capabilities to interact with Advanced Program-to-Program Communications (APPC) applications over both a hierarchical SNA network and a peer network. The LU 6.2 Application Program Interface (API) provides the tools and routines that allow programmers to write APPC programs that use the resources of the IRIS SNA LU 6.2. All standard APPC verbs are supported.IRIS SNA 3770
The IRIS SNA 3770 emulator software provides end users of IRIS workstations and servers an easy-to-use 3770 Emulator for accessing IBM host-based 3770 SNA applications. The software emulates an IBM 3776 Model 3 terminal. Features include support for both binary and text data, spooling of multiple jobs, and an on-line help facility for 3770 user commands.
Hardware-related SNA SERVER products are the SDLC and token ring communications boards, either or both of which can be installed on the VME bus-based IRIS-4D systems.
For detailed information about IRIS SNA SERVER features, see Appendix A.
The IRIS SNA SERVER software is installed in the following directories:
| /usr/sna/bin | Key executables | |
| /usr/lib | ||
| /usr/include/sna | API include files | |
| /usr/sna/snaview | X Window/Motif-based tool and help files | |
| /usr/sna/rsrc | ||
| /usr/sna/tp | Transaction programs and all VT100-based interface | |
| /usr/sna/etc | ||
| /usr/sna/diag | ||
| /usr/sna/log | ||
| /usr/sna/sample | Sample LU 6.2 programs |
IRIS SNA SERVER provides support for Logical Unit types 0, 1, 2, and 3 of the IBM System Network Architecture. With LU 0-3 functionality, an application operating on a VME-based IRIS-4D Series workstation can implement terminal-emulation software for devices in the IBM 3270 and 3770 families and can provide the session transport and statistics-gathering support required by Communication Network Management applications.
An application accesses the services of IRIS SNA SERVER through function calls, or verbs. The LU 0-3 verbs are called the Programmable Interface, or PI, verbs. With the PI verbs, an application controls Logical Unit (LU) or Physical Unit (PU) sessions at the Data Flow Control level.
LU 0-3 API is included as part of the IRIS SNA SERVER software package. A software programmer, however, can use the LU 0-3 verbs to customize an interface to 3270 and 3770 functions. A single IRIS SNA SERVER is capable of supporting LU 0, LU 1, LU 2, LU 3, and LU 6.2 sessions at the same time. Because of the level of integration, all of these session types can occur simultaneously over one link to a host. Thus, a single application is capable of accessing all of the session types through the provided verb interfaces.
For detailed information about LU 0-3 features, see Appendix A.
IRIS SNA LU 6.2 is a communications package designed to take advantage of the IBM Systems Network Architecture peer-to-peer application capabilities. These capabilities provide interprocess communication services within both host-terminal and peer-to-peer environments and are governed by specific protocols.
Through the IRIS SNA SERVER, IRIS SNA LU 6.2 supports the IBM SNA LU 6.2 protocols, which manage communications between two programs. LU 6.2, also known as Advanced Program-to-Program Communications (APPC), defines communications as client-server programs, one running locally and one running remotely on a partner system. These programs use simple commands, called verbs, to exchange data, transmit requests, and receive replies.
For detailed information about IRIS SNA LU 6.2 features, see IRIS SNA LU 6.2 Programming Guide.
The IRIS SNA SERVER can be configured to provide IBM host connectivity or peer-to-peer connectivity via a token ring network. The IRIS SNA SERVER is co-located in a IRIS-4D workstation or server that has an IRIS Token Ring board installed. By emulating a downstream IBM 3174, the IRIS SNA SERVER acts as a gateway for IRIS systems running IRIS 3270 or IRIS 3770 emulator software or IRIS LU 6.2 transaction programs. The IRIS systems can access the gateway from a variety of network configurations. The IRIS Emulators help boost end-user productivity by adding 3270 and LU 6.2 functionality to the high-performance IRIS system. From a single vantage point, an end user can access multiple mainframe-based applications including CMS, CICS, IMS, PRO, and DISOSS. An end user can also perform detailed design analysis locally using workstation-based applications.
The IRIS Token Ring provides simultaneous access to mainframe and IRIS-4D system-based applications. The IRIS-4D system can be configured to reside on both Token Ring and Ethernet® networks and can serve as an IP router for other IRIS-4D systems.
For additional information regarding IRIS Token Ring features, see
Appendix A.
Figures 1-2 through 1-4 show the network configurations that are supported by this product. The following terms are used in these figures:
Figure 1-2 shows an IRIS SNA SERVER acting as a gateway for IRIS SNA applications. The IRIS SNA SERVER communicates to the IBM mainframe through a 3174 channel attached controller.
Figure 1-2 shows an IRIS SNA SERVER acting as a gateway for IRIS SNA applications. The IRIS SNA SERVER communicates to the IBM mainframe through a 3174 channel attached controller, and the IRIS SNA applications communicate to the gateway through Ethernet.
Figure 1-3 shows an IRIS SNA SERVER acting as a gateway for IRIS SNA applications. The IRIS SNA applications communicate to an IP router on the token ring through Ethernet. The IRIS SNA SERVER communicates to the IBM mainframe through a 3174 channel attached controller.
An IRIS SNA SERVER can theoretically connect to an IBM host from a token ring through a 3174 Local SNA Cluster Controller, a 3172 Interconnect Controller, or a 3725 or 3745 Communications Controller.
The IRIS SNA SERVER cannot act as a token ring gateway PU. A token ring gateway PU is an SNA device on a token ring that is directly connected to an IBM host through a channel attach. Instead, the IRIS SNA SERVER must be configured so that the workstation appears as a downstream PU (DSPU) device to IBM hosts.
SNA protocol and Source Routing are used for communication between the IRIS SNA SERVER for token ring and a token ring gateway PU.
TCP protocol is used for communication between the IRIS SNA SERVER for token ring and an IRIS SNA application product such as IRIS SNA 3270, IRIS SNA 3770, or IRIS SNA LU 6.2. An IP router or a bridge that supports the IBM Source Routing Transparent specification is required for communication across rings.
Peer-to-peer (workstation to workstation) connection requires that the IRIS SNA SERVER emulate Node Type 2.1 and utilize LU 6.2 protocols. For peer-to-peer connection of two workstations on different rings, the rings must be connected by one bridge or a series of bridges that support Source Routing.
The IRIS SNA SERVER can be configured to provide IBM host connectivity or peer-to-peer connectivity via an SDLC link. The IRIS SNA SERVER is co-located in a IRIS-4D workstation or server that has an IRIS SDLC board installed. The IRIS SNA SERVER acts as a gateway for IRIS systems running IRIS 3270 or IRIS 3770 emulator software or IRIS LU 6.2 transaction programs. The IRIS systems can access the gateway from a variety of network configurations. The IRIS Emulators help boost end-user productivity by adding 3270 and LU 6.2 functionality to the high-performance IRIS system. From a single vantage point, an end user can access multiple mainframe-based applications including CMS, CICS, IMS, PRO, and DISOSS. An end user can also perform detailed design analysis locally using workstation-based applications.
Figures 1-5 through 1-7 show the network configurations that are supported by this product. The following terms are used in these figures:
Figure 1-4 shows an IRIS SNA SERVER acting as an SDLC gateway for IRIS SNA applications on a token ring. The IRIS SNA SERVER communicates to the IBM mainframe through a 3745 communications controller or an ICA installed in the IBM mainframe. The SDLC line can be either RS-232 or V.35.
Figure 1-5 shows an IRIS SNA SERVER on a token ring acting as an SDLC gateway for IRIS SNA applications on an Ethernet. The IRIS SNA SERVER communicates to the IBM mainframe through a 3745 communications controller or an ICA installed in the IBM mainframe. The SDLC line can be either RS-232 or V.35. The IRIS SNA applications on an Ethernet communicate to the IRIS SNA SERVER using an IP router.
Figure 1-6 shows an IRIS SNA SERVER on an Ethernet acting as an SDLC gateway for IRIS SNA applications. The IRIS SNA applications on the token ring communicate with an IP router on the token ring. The IP router is connected by Ethernet to the IRIS SNA SERVER. This figure also shows that the IRIS SNA SERVER can communicate with IRIS SNA applications through Ethernet (no token ring). The IRIS SNA SERVER communicates to the IBM mainframe through a 3745 communications controller or an ICA. The SDLC line can be either RS-232 or V.35.
For additional information on IRIS SDLC features, see Appendix A.