SNAX/HLS Configuration and Control Manual

The SNAX/HLS Server Process
Product Overview
104705 Tandem Computers Incorporated 1–7
The SNAX/HLS Server
Process
The SNAX/HLS server process is a multithreaded process that interfaces both to the
SNAX/HLS application and to the SNALU interface of the Tandem access method,
that is, SNAX/XF or SNAX/CDF. Its primary functions are to perform verb requests
and to produce verb replies for applications. Typically, verb requests result in one or
more SNA messages flowing to the session partner on behalf of the application, as
shown in Figure 1-2. Referring to this figure, the highlights of the flow are as follows:
1. The requester delivers a message (that is, verb request with data) to the
SNAX/HLS server for transmission to the session partner.
2. The SNAX/HLS server formats the message into appropriate SNA message units
(chain elements), handles required aspects of SNA protocol, and delivers SNALU
headers with data to SNAX/XF or SNAX/CDF.
3. SNAX/XF or SNAX/CDF formats each chain element into the appropriate SDLC
format (segments), handles SDLC addressing, and transmits each frame on the
data link.
4. SNAX/XF or SNAX/CDF receives a series of SDLC frames that constitute the
session partner’s reply. SNAX/XF or SNAX/CDF assembles each chain element
and delivers it to HLS.
5. The SNAX/HLS server receives chain elements from SNAX/XF or SNAX/CDF
and assembles the chain elements into a logical message.
6. The application receives a verb reply consisting of a reply header plus data
provided by the session partner.