Diagnosing SNALINK LU6.2 problems

This topic describes how to diagnose problems with the SNALINK LU6.2 function and contains the following subtopics:

The SNALINK LU6.2 interface uses the LU type 6.2 protocol to establish a point-to-point connection across a SNA network. SNALINK LU6.2 is capable of establishing a connection with any system that runs TCP/IP and uses the LU type 6.2 protocol.

The SNALINK LU6.2 interface is similar to the SNALINK LU0 and X.25 NPSI interfaces with the connection involving several subsystems. The components of the SNALINK LU6.2 network are shown in Figure 1.

Figure 1. Components of a SNALINK LU6.2 connection on MVS

Diagram that shows the components of a SNALINK LU6.2 connection on MVS. It is a point-to-point connection between an MVS local host and an MVS remote host, which involves several subsystems, across a SNA network.

Following is a brief description of the component interaction and data flow that occurs when data is transferred over a SNALINK LU6.2 network. Each component is cross-referenced to the figure.

1: Data is generated and encapsulated on the TCP/IP address space and is passed to the SNALINK LU6.2 address space through a DLC connection.
2: The SNALINK LU6.2 address space handles all establishment, aging, and termination of SNA network connections in a manner transparent to the TCP/IP address space. The data is then sent to the local system SNA subsystem. f MVS™ hosts, this subsystem is VTAM®.
3: VTAM APPC routines are used to pass the data to the SNA network.
4: VTAM routines on the destination system receive the data and pass it through to the SNALINK LU6.2 address space.
5: The SNALINK LU6.2 address space sends the data to the TCP/IP address space using a DLC connection.
6: The data is unencapsulated and processed by the TCP/IP address space.