Using the Network Status Variables

 PcVue provides a large number of network status variables provided and it may appear at first that the information provided by some of them is duplicated.

Connection Status and Connection Activity Variables

The connection activity variables indicate if a connection is active. That is a node of PcVue is using the connection for exchange of information with another node. A connection can only become active if it is already available

The connection status variables indicate if a connection is available. That is the physical network connection is available to the corresponding PcVue node.

On a system with just one network, the connection status variables and the connection activity variables will have the same values.

On a system with dual networks, one of the networks may have an active server connection whilst the other has an active client connection, or both client and server connections might use the same network with the other network having no active connections. In either case, should a connection become unavailable all activity automatically transfers to the other. The following picture shows the status of a simple client server system with dual networks. Both networks are available. The client and server connections both using one network whilst the other is available but inactive. Show picture

The corresponding values of the status variables are: Show picture

OK_NUMBER and ACTIVE_NUMBER variables

The ACTIVE_NUMBER variables indicate the number of remote nodes with which a local node is actively exchanging information.

The OK_NUMBER variables indicate the number of remote nodes available to a local node.

On a system with one network, the ACTIVE_NUMBER and OK_NUMBER variables will have the same values.

On a system with dual networks, only one of the connections to a remote node may be active at one time and the ACTIVE_NUMBER and OK_NUMBER variables may have different values.

In the picture above, both the client and server connections are using node 0. Therefore, the OK_NUMBER and ACTIVE_NUMBER variables for node 0 have the same values, whereas node 1 has a value of 1 for its OK_NUMBER variables but the ACTIVE_NUMBER variables are 0.