Special considerations for SNA NJE networking

Controlling SNA NJE networking is similar to controlling binary synchronous communication (BSC) networking. However, because VTAM® controls SNA NJE application-to-application sessions, you must meet certain VTAM requirements before establishing a session between two JES2 nodes. See z/OS Communications Server: SNA Resource Definition Reference for descriptions of the VTAM definitions needed. To establish a session:

You must start VTAM before you establish a session between 2 nodes. VTAM must have the application names defined for the starting node and for all nodes eligible for application-to-application sessions with other nodes in the network.
The VTAM network must complete its initialization. This includes activating the IBM® 3704, 3705, 3720, 3725, or 3745 Network Control Programs, synchronous data link control (SDLC) links, and all participating VTAM cross-domain resource managers.
LOGON(nnn) initialization statements must uniquely define each JES2 subsystem to VTAM.
In the networking environment, each JES must have a unique application name. JES2 uses a default name if APPLID= is not specified on the LOGON(nnn) statement. You should always code the APPLID= parameter on the LOGON(nnn) statement because only one subsystem in the network can use the default name of JES2.

The APPL(avvvvvvv) initialization statement defines the VTAM application name for each node with which an installation plans to connect. In addition, the APPL(avvvvvvv) statement specifies the specific characteristics of an application session. If an application name matches the NAME= parameter on the NODE(nnnn) statement, JES2 can create an APPL(avvvvvvv) statement dynamically during sign on through a $S N command.

Installations should ensure that the APPL(avvvvvvv) initialization statement is properly specified before attempting to initiate sign on with another node. If the APPL(avvvvvvv) provides an incorrect node name (NODE=), line (LINE=) or compaction table (COMPACT=), installations can often establish a VTAM session, but are unable to activate the NJE session.
LINE(nnnn) JES2 initialization statements must define (with the UNIT=SNA parameter) the paths for each NJE session.
NODE(nnnn) initialization statements define all NJE applications participating in the network.
The operator must issue a $S LOGON(nnn) (start logon) command to connect the NJE application with VTAM.

When you meet the VTAM session requirements, you can start a session with another eligible JES2 NJE application by issuing the $S N command with the appropriate application or node name specified.