APPN flows

This appendix describes the flows between APPN end nodes, network nodes, interchange nodes, and the subarea network. The flow diagrams are divided into the following categories:

Table 1 lists all the APPN flows illustrated here.

Table 1. Index of APPN flows
APPN flow	Page
CP-CP session flow	Page
Activating a CP-CP contention loser session	Figure 1
Activating a CP-CP contention winner session	Figure 1
Activating an APPN Host-to-Host Channel	Figure 1
Activating a leased APPN Node type 2.1	Figure 1
Host CP initiating deactivation of CP-CP session	Figure 1
Remote node initiating deactivation of CP-CP session	Figure 1

Dependent LU server flow	Page
Single subnetwork
Activating resources
CPSVRMGR pipe activation, DLUR-Initiated	Figure 1
CPSVRMGR pipe activation, DLUS-initiated	Figure 1
Dependent LUs, dynamic registration and activation of	Figure 1
Dependent LUs, activation of pre-defined	Figure 1
	Figure 1
SSCP-PU session activation race	Figure 1
Deactivating resources
CPSVRMGR pipe deactivation	Figure 1
Downstream PU outage	Figure 1
REQDISCONT (immediate) received from downstream PU	Figure 1
REQDISCONT (normal) received from downstream PU	Figure 1
LU-LU sessions
APPN PLU-initiated to a dependent SLU	Figure 1
Session termination, USS flows for	Figure 1
USS SLU-initiated to APPN PLU	Figure 1
USS SLU-initiated to subarea PLU	Figure 1
SSCP-PU, SSCP-LU session deactivation
Forced	Figure 1
Normal	Figure 1
With Giveback (ANS=CONT)	Figure 1
With Giveback (ANS=STOP)	Figure 1
Cross subnetwork
PLU-Initiated Session with DLUS and DLUR within Different Subnetworks	Figure 1
PLU-Initiated Session with DLUS and PLU in one Subnetwork and DLUR in Another	Figure 1
SLU-Initiated Session with DLUS and DLUR within Different Subnetworks	Figure 1
Directory services flow	Page
Locate resource
APPN and subarea Network	Figure 1
APPN network, complex	Figure 1
Complex APPN network using more than one CDS	Figure 1
CP-CP session terminates	Figure 1
CP network broadcast initiation	Figure 1
EN to NN	Figure 1
EN to NN to EN	Figure 1
EN to NN to NN to NN	Figure 1
EN to NN to subarea network	Figure 1
EN to NN to two ENs	Figure 1
NN receives network broadcast request	Figure 1
NNS of the OLU is at pre-V4R2 level	Figure 1
Directory search verification reduction	Figure 1
SLU-initiated session	Figure 1
Register resource
EN to NN to CDS	Figure 1
With error recovery	Figure 1
High Performance Routing (HPR) flow	Page
Rapid-transport protocol (RTP) connection over portion of session path	Figure 1
Rapid-transport protocol (RTP) across composite nodes with a T2.1 connection through NCP	Figure 1
Rapid-transport protocol (RTP) across composite nodes with a T2.1 connection through VTAM®	Figure 1
Rapid-transport protocol (RTP) across composite nodes with a virtual-route-based transmission group, NCP does ANR routing	Figure 1
Rapid-transport protocol (RTP) across composite nodes with a virtual-route-based transmission group, VTAM does ANR routing	Figure 1
Two rapid-transport protocol (RTP) nodes with a T2.1 connection	Figure 1
Two rapid-transport protocol (RTP) nodes with a virtual-route-based transmission group	Figure 1
LU-LU sessions flow	Page
APPN network...NNS--EN (PLU)
SLU-initiated, no queueing	Figure 1
SLU-initiated, queued by the PLU	Figure 1
APPN network...NNS--EN(SLU)
PLU-initiated, no queueing	Figure 1
PLU-initiated, queued by the SLU	Figure 1
APPN network (PLU)…ICN==SA(SLU), PLU-Initiated
Directed search without required precomputed RSCV	Figure 1
No queueing	Figure 1
Queued by SLU	Figure 1
Search-only flow transformed into a DSRLST	Figure 1
USERVAR resolution required	Figure 1
APPN network (PLU)…ICN==VR-based TG==ICN…APPN network (SLU)
PLU-initiated	Figure 1
APPN network (SLU)…ICN==SA(PLU)
Autologon, PLU not available initially	Figure 1
SLU-initiated, no queueing	Figure 1
SLU-initiated, queued by the PLU	Figure 1
CLSDST PASS; SLU is single-session capable
From APPN to subarea	Figure 1
Through APPN	Figure 1
EN-NN-EN, PLU-initiated, no queueing (including BIND flows for intermediate network node)	Figure 1
EN (PLU)--NNS…APPN network
PLU-initiated, no queueing	Figure 1
PLU-initiated, queued by the PLU	Figure 1
PLU-initiated, queued by the SLU	Figure 1
EN (SLU)--NNS…APPN network
SLU-initiated, no queueing	Figure 1
SLU-initiated, queued by the PLU	Figure 1
Intermediate Network Node (INN) BIND. The LOCATE did not go through this node.	Figure 1
SA (PLU)==ICN…APPN network (SLU)
DSRLIST transforming into PLU-initiated, search-only	Figure 1
PLU-initiated, no queueing	Figure 1
PLU-initiated, queued by the SLU	Figure 1
PLU-initiated, USERVAR resolution required	Figure 1
SA (SLU)==ICN....APPN network (PLU)
Autologon, PLU not available initially	Figure 1
SLU-initiated, no queueing	Figure 1
SLU-initiated, queued by the PLU	Figure 1
Session release request
SA(PLU)==ICN…APPN network(SLU)	Figure 1
SA(SLU)==ICN…APPN network(PLU)	Figure 1
Session termination, forced
SA(PLU)==ICN…APPN Network(SLU), pending active session. PLU is accessible without going into APPN.	Figure 1
SA(PLU)==ICN…APPN Network(SLU), queued session	Figure 1
SA(PLU)==ICN…APPN Network(SLU), queued session. PLU is accessible without going into APPN.	Figure 1
SA(SLU)==ICN…APPN Network(PLU), pending active session	Figure 1
Session termination, orderly
SA(PLU)==ICN…APPN Network(SLU), active session	Figure 1
APPN Network(PLU)…ICN==SA(SLU), active session	Figure 1

Many abbreviations are shown at the top of the flow diagrams. The following list gives the meaning of those abbreviations:

ANR: Automatic network routing
APPC: Advanced program-to-program communication program
BF: Boundary function
CDS: Central Directory Server
CP: Control point
DLUR: Dependent logical unit requestor
DLUS: Dependent logical unit server
EN: End node
ICN: Interchange node
LU: Logical unit
NN: Network node
NNS: Network node server
PLU: Primary logical unit
PU: Physical unit
PUNS: Physical unit services
RTP: Rapid-transport protocol
SLU: Secondary logical unit
SSCP: System services control point
TP: Transaction program
TSC: Transmission subsystem component