OSI/AS Configuration and Management Manual

OSI/AS Subsystem Description
OSI/AS Configuration and Management Manual—424119-001
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TSP Process
TSP Process
The TSP process (OSI/TS) provides reliable end-to-end data transfer. It acts as the
provider for the Session Layer (the TAPS process) and is the user of the Network Layer
(X25AM) and Data Link Layer (TLAM for D-series releases and PAM and SLSA for
G06 and above releases) services. The TSP process has its own trace capability.
Downward Information Flow
The TSP process accepts primitives from the TAPS process through file-system calls to
the TSP subdevice. The TSP subdevice is added by the OSI manager process when the
application registers an APS_ASSOC_ATTACH_ or an
APS_ASSOC_CONNECTREQ_ procedure call.
The following PTrace example shows a file-system call from the TAPS process. In this
case, the file-system call is a WRITEREAD with the MCW set to accept a
T-CONNECT (%H8000, in the bottom line):
File-system requests from the TAPS process are then passed to the service level within
the TSP process as T-CONNECT attach primitives. The following trace shows an
example of a T-CONNECT attach primitive traced by the TSP process:
The TSP process then formats incoming transport primitives into transport protocol data
units (TPDUs). The TSP process sends the TPDUs to the NSP process as Network
Layer primitives.
If the NSP is an X25AM process, the TSP process forwards the TPDUs to the NSP
process in file-system calls to the X25AM subdevice. If the NSP is a TLAM process on
D-series releases (or PAM on G06 and above releases), the TSP process adds an IPPDU
(internet-protocol protocol data unit) header to the TPDUs, according to the OSI IP
(internet protocol). The TPDUs are then sent to and received from the TLAM (or PAM)
port in file-system calls.
The following PTrace example shows the same connect request TPDU (CR-TPDU)
shown in the previous trace example. This CR-TPDU was sent to X25AM and received
by the NSP process as an N-data indication:
17:11:52:920 >000.010 #17 Msg IO
WRITEREAD Req Tag: 1 File: 4 Syncid: 1 Wrlen: 2 Rdlen: 34 SU: #Z000006
P1: -32768
000: 8000
17:11:52:960 >000.040 #19 T-Primitive
T-CON attach BufLen: 0 Addr: 1930676 SU: #Z000006
9/23/91 17:11:53.934480 >000.000 #44 L3 Primitive
N-DATA indication NCB Index: 0 Buflen: 30 Addr: 1929808 SU: #TSP1004