A processor enters the XCS network when HIPLEX MSCF is started (see "Starting HIPLEX MSCF"). Depending on the entry in the subsystem catalog, HIPLEX MSCF is started either when the MSCF subsystem is started in the course of the BS2000 startup procedure, or at a later stage through an explicit START-SUBSYSTEM MSCF command. Use of a configuration file is mandatory for XCS entry.
The registered functions necessary for entering the network are initialized by configuration management (XCM) in the local initialization phase of HIPLEX MSCF. The NSM and XCS-TIME subsystems required for this are automatically loaded later by MSCF. If this is not possible, MSCF too terminates again.
If the local initialization phase is concluded successfully, the communication system initiates the connection setup to the partner processors predefined in the configuration file. If a partner is active and is defined as the HIPLEX MSCF partner, an MSCF connection is established between the local processor and the partner processor. Otherwise, the partner processor is not noted as connected (see "Establishing connections").
When the connection setup phase has concluded, configuration management determines the XCS status of the active HIPLEX MSCF partner. If the XCS network does not yet exist, the processor establishes the network (Create). If the XCS network already exists, the processor enters this network (Join) and the partner processors add the processor to the network (join reconfiguration).
The registered functions are started in succession on the processor joining the network. The XCS functionality managed by each of the functions is made available on the processor. When a processor joins a network, each function implements a join reconfiguration in conjunction with its partner entities.
The network setup is concluded when all functions have been started successfully. Network entry is not completed, however, until the processor has also been successfully added to the network on all partner processors.
If HIPLEX MSCF has been terminated on a processor, the processor can only rejoin the XCS network when HIPLEX MSCF is restarted if the appropriate leave or fail reconfiguration has been completed in full on the partner processors and the processor is no longer known to the network. If this condition is not fulfilled, the active partner processors will reject the connection request of the processor.
Notes
Connection requests from CCS partners will be rejected at first. After the processor joins the XCS network, connections will be established to these partners.
It is only possible for a processor to join an existing XCS network if CCS connections have been established to all active sharers. If this is not the case, the start of HIPLEX MSCF will be aborted.
If no connections are set up to any of the active XCS partners due to an error, the processor itself attempts to establish the XCS network (Create). When importing the XCS pubset, however, the processor determines that other processors are entered on the pubset. Message DMS13C7 is then output, requesting systems support to decide whether the master processor entered can be ignored. However, since the other XCS partners are still active, the import must be aborted in this case (input: <tsn>.N). HIPLEX MSCF is terminated abnormally.
While a processor is joining the network, no other processor can be added to the network or leave the network. Such operations are delayed until the network entry is completed.
If the network is in a reconfiguration phase, the entry of a processor is delayed until this phase is concluded. If necessary, the processors to be reconfigured should be checked to determine whether the reconfiguration is blocked.
If the XCS network is corrupted due to a connection failure or a processor crash, or if such an error occurs while a processor is joining the network, the start of HIPLEX MSCF is aborted and the MSCF subsystem is terminated. A fail reconfiguration is initiated on the partner processors. When the fail reconfiguration is concluded on the partner processors and the error has been rectified, the network entry can be restarted by issuing the START-SUBSYSTEM MSCF command.