6100 ADCCP Programming Manual

ADCCP/X21 Protocol Task Architecture
ADCCP/X21 Protocol Module
3–2 069225 Tandem Computers Incorporated
ADCCP/X21 Protocol
Task Architecture
ADCCP/X21 uses almost the same protocol task architecture as 6100 ADCCP. (Refer
to Section 2, “ADCCP Link and Station Management,” for a description of the ADCCP
protocol task.) The 6100 ADCCP protocol module and the ADCCP/X21 protocol
module both use the following:
Protocol Manager
Station Manager (Level 2 Protocol)
Link Manager (Level 1 Protocol)
However, ADCCP/X21 differs from the ADCCP protocol module in the following
ways:
A different driver handles the X.21 LIM, X.21 Patch-Panel, or X.21 backplane
interconnect card (BIC) interface.
A call control task module manages the special X.21 call control features during
connection establishment and release.
Figure 3-1 shows the main software components in the ADCCP/X21 protocol module.
Figure 3-1. ADCCP/X21 Software Components
ADCCP
Protocol
Task
Call-Control
Task
X.21
Driver
X.21
LIM
To Host
X.21
Interface
Circuits
CLIP 1
013
ADCCP Protocol Task The protocol task does most of its work after an X.21 connection has been established
and your application is ready to start an ADCCP link and transfer data. The protocol
task provides the same protocol management, station management, and link
management functions provided by 6100 ADCCP, but the protocol task provides these
functions only after the call-control task has completed call-establishment procedures.
The functions of the protocol task thus depend on the state of the line: