ViewPoint Manual

Functional Description
ViewPoint Manual—426801-001
5-26
Event Distribution in Networks
log—just like the primary-events distributor. However, in this case, you can specify
your own filter for reading only selected events (note the filter shown attached to the
alternate-event distributor). That is something you cannot do with the primary-
events display.
3. If you specify historical mode for your alternate-event display (by specifying a date
and time), your alternate-event distributor reads historical events from either the
current log set or (as shown in Figure 5-18) from an archived log file. As in the
preceding case, you can specify your own filter for reading selected events from that
file.
In either of cases 2 or 3 above, if some other operators choose to read from the same log
file that you are accessing, those operators have their own alternate-event distributors
and their own filters.
Event Distribution in Networks
Up to this point, only a single system has been considered. In the case of the multiple
nodes of a network, event messages must be distributed from originating nodes to one or
more NCNs. There are several ways to do this kind of distribution. The more common
method uses a special kind of event distributor, called a forwarding distributor. Another
method specifies multiple collectors on the remote nodes as the source of events. A
third method specifies only the event collector on a remote node. For EMS distributors
running on C-series systems, ViewPoint gives full support.
When events are forwarded, there is one forwarding distributor on each node for each
NCN. That is, if two NCNs are in a network, separate forwarding distributors are
required to send event messages to the two NCNs. When multiple collectors are
specified, then the events from each remote collector are merged by the ViewPoint event
collection server on each receiving NCN. When a single remote collector is used,
ViewPoint starts a remote distributor on that node to distribute events to the local
NCN—unless the configuration specifically assigns a distributor to a particular node.
Each of these methods is discussed in more detail in the following subsections.
Forwarding Distributors
Figure 5-19 is a simplified example of the collection and distribution of primary events
in a network. It focuses on the role of the forwarding event distributors. (For simplicity,
the subsystem processes and the event collector are not shown in this figure.)
Previously shown in Figure 5-18, event messages from the subsystems are collected and
recorded in the current event log file by the event collector.
The diagram in Figure 5-19 shows one NCN and four remote nodes. Each node,
including the NCN, records event messages in its current log file. Each forwarding
event distributor in the four remote nodes distributes event messages from its associated
current log to the event collector located in the NCN. The NCN event collector merges
all these incoming event messages from other nodes with messages generated locally
and records them in its own current log file.