APN Configuration and Management Manual

SNAX/APN Advanced Program-to-Program

Communication (APPC)

SNAX/XF and SNAX/APN Configuration and Management Manual—425836-006

6-2

XID Validation

In node type 2.1 operation, link stations send each other format 3 exchange

identification information frames (henceforth called XID3 frames). Each link station

validates the information received from the other by comparing that information against

some defined parameters and either accepting or rejecting the connection. This

validation is done whether a line is switched or nonswitched.

The information normally used to validate XID3 frames is a combination of a control

point name and SNA network identifier. SNAX/APN compares these values with the

CPNAME and SNANETID values configured for the LU (or their defaults). If the

CPNAME has not been configured for a remote PU that is configured as a network

node, the CPNAME is taken dynamically from the XID3 frame received from the

adjacent node.

If the XID3 frame does not contain values for these, SNAX/APN compares the IDBLK

and IDNUM values (always in the XID3 frame) with the PUIDBLK and PUIDNUM

values configured for the PU. If the PUIDBLK value is %H000 or %HFFF, SNAX/APN

accepts the connection anyway.

Figure 6-1. Multiple and Parallel Sessions

Multiple Parallel

TNLU1 IBMLU1

IBMLU2

IBMLU3

NonStop LEN Node Partner 2.1 Node

TNLU2

Multiple

Parallel

TNLU3 IBMLU4

VST601.vsd