Interoperability with IBM Host Systems
Interoperability with IBM Host Systems |
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SNA Server provides 3270 connectivity through dependent 3270 LUs. 3270 LUs are dependent because they require a mainframe to function. Each 3270 LU defined within SNA Server is configured to use an existing connection to the mainframe system and corresponds to a matching LU resource allocated on the host computer, usually specified within VTAM. The 3270 LU definition in SNA Server is identified by a number and a user-specified name. The number matches the number of the corresponding LU resource on the mainframe.
The 3270 LU is further classified by the type of service provided over the connection. Like PUs, LU types are designated by numbers. For example, 3270 display data streams are known as LU 2. A 3270 LU , as shown in Figure 10.8, can be configured as one of the following:
Figure 10.8 3270 Connectivity Using SNA Server
SNA Server Client software must be installed on each client that uses SNA Server LU services. The client software manages communications between a 3270 application and the server running SNA Server. Applications designed to use the SNA Server Client API use the LUs defined within SNA Server to establish a communications link from the client to the mainframe through SNA Server.
The link between the LU definition in SNA Server and the host LU resource is called a session. Sessions can be permanent and automatically started during initialization, or established on an as-needed basis. Concurrent sessions can share the same physical devices and communications links.
