.-ENBCAST--=--NO------. >>-+---------------------+------------------------------------->< | .-NO--. | '-ENBCAST--=--+-----+-' '-YES-'
- ENBCAST=NO
- Specifies that the network node server is not allowed to search the end node for unknown resources.
- ENBCAST=YES
- Specifies that the network node server is allowed to search the
end node for unknown resources. This will result in the end node
being searched on all broadcast searches, which could have an impact
on performance.
This operand can be used to enable the generic resource function to operate with a network node server that is not connected to the same generic resource structure as the end node. Because of the possible performance impact, this is intended as a backup mode of operation only; therefore, ENBCAST=YES should be coded only on the NETSRVR definition statement of a backup network node server.
In addition, this backup mode of operation works only when all end nodes connected to the same generic resource structure are using the same backup node as their network node server. For this reason, it is necessary to configure all of these end nodes such that they will switch to the backup-mode network node server only when the primary network node server fails (rather than, for example, when a link failure occurs).
Recommendations:- Configure all end nodes attached to the same generic resource structure with the same network node server (NETSRVR) list. The first entry in the network node server list should define the primary network node server (that is, the network node that is attached to the same generic resource structure as the end nodes) and should specify (or default to) ENBCAST=NO. The second (and last) entry in the list should define the backup-mode network node server and should specify ENBCAST=YES. (In order to guarantee that all end nodes switch to the backup-mode network node server at the same time, all end nodes must define with the same primary and backup-mode network node server names.)
- Code ORDER=FIRST in the network node server (NETSRVR) list, so that the end nodes will always attempt to use the primary network node server (the one attached to the same generic resource structure) first.
- Code the NNSPREF start option on all end nodes with the name of the primary network node server (the one attached to the same generic resource structure). This will cause all end nodes to automatically terminate the backup-mode of operation by switching back to the primary network node server as soon as it becomes available again.
- To reduce the possibility of a link failure causing only some end nodes to switch to the backup-mode network node server, it is recommended that redundant links (which support CP-CP sessions) be defined between each end node and its primary network node server. XCF links are a very good choice for this, because they provide the necessary connectivity as long as there is connectivity to the coupling facility. (In fact, because connectivity to the coupling facility is required to support generic resources, defining XCF links may eliminate the need to define redundant links specifically for this purpose.)