SNAX/HLS Configuration and Control Manual

Pacing Throughput Considerations
Interpreting SNA Protocol
7–4 104705 Tandem Computers Incorporated
Pacing-Throughput
Considerations
SNAX/HLS supports pacing. When planning high-throughput sessions, you may
want to specify a large pacing window size for the flow of data into SNAX/HLS. To
allow for efficient line utilization, SNAX/HLS sends the pacing response (assuming
that the pacing indicator has arrived) as soon as it is specified by the pacing-window
size attribute. The response is not withheld, however, if the only data queued to the
application is a partial message and the application is not using the LARGE-
MESSAGE-OPTION.
You should be aware, however, that this implies that SNAX/HLS might have to buffer
up to (2*window_size - 1) messages at any one time and that this places demands upon
dynamic memory.
Single-Stage and
Two-Stage Pacing
The BIND image defines pacing values for both the primary and secondary session
partners. For secondary half-sessions, SNAX/HLS always uses the values in bytes 8
and 9. For primary half-sessions, SNAX/HLS uses the secondary's values if single-
stage pacing is indicated for a particular flow and uses the primary session’s values if
two-stage pacing is indicated.