The following are examples of how the values set for CMPVTAM,
CMPAPPLI, and CMPAPPLO work together to determine the compression
levels for a session. Figure 1 shows a sample
configuration.
Figure 1. Data compression
yield
For the examples, assume the values shown in Table 1. Also assume that COMPRES=REQD is specified
on the logon modes used for the sessions.
Table 1. Compression values for example of data compression yield| VTAM1 |
APPL1 |
APPL2 |
VTAM2 |
|---|
| CMPVTAM = 4 |
CMPAPPLI = 4 |
CMPAPPLI = 4 |
CMPVTAM = 3 |
| |
CMPAPPLO = 1 |
CMPAPPLO = 2 |
|
In the first example, APPL1 is the PLU and APPL2 is the
SLU.
- VTAM® determines that the
requested PLU-to-SLU level (which is the lower of the values specified
on the CMPVTAM start option for VTAM1 or the CMPAPPLO operand for
APPL1) is 1.
- VTAM determines that the
requested SLU-to-PLU level (which is the lower of the values specified
on the CMPVTAM start option for VTAM1 or the CMPAPPLI operand for
APPL1) is 4.
- APPL1 passes the requested levels to APPL2 on the BIND.
- VTAM compares the requested
levels to the VTAM2 CMPVTAM level. APPL2 determines that the actual
PLU-to-SLU level for this session is 1 and the actual SLU-to-PLU level
for this session is 3.
- APPL2 returns the actual levels on the BIND(RSP).
In the second example, APPL2 is the PLU and APPL1 is the
SLU.
- VTAM determines that the
requested PLU-to-SLU level (which is the lower of the values specified
on the CMPVTAM start option for VTAM2 or the CMPAPPLO operand for
APPL2) is 2.
- VTAM determines that the
requested SLU-to-PLU level (which is the lower of the values specified
on the CMPVTAM start option for VTAM2 or the CMPAPPLI operand for
APPL2) is 3.
- APPL2 passes the requested levels to APPL1 on the BIND.
- VTAM compares the requested
levels to the VTAM1 CMPVTAM level. APPL1 determines that the actual
PLU-to-SLU level for this session is 2 and the actual SLU-to-PLU level
for this session is 3.
- APPL1 returns the actual levels on the BIND(RSP).
z/OS Communications Server: SNA Network Implementation Guide
Copyright IBM Corporation 1990, 2014