Defining the bridge facility name

When CICS® creates a bridge facility, it creates both an eight-byte token to identify it (the facilitytoken) and a four-character terminal identifier, which is used as both TERMID and NETNAME.

The facilitytoken is returned on the Link3270 allocate call and must be supplied by you on all subsequent session mode calls ( See Using Link3270 session mode).

For bridge facilities created by the Link320 bridge, the token and name are unique across the CICSplex, and the TERMID and NETNAME are of the form AAA}. Naming occurs in the routing region, at the time of processing an allocate command in session mode, or the internal allocate step in single-transaction mode. See Using the Link3270 bridge for information about session and single-transaction modes.

Link3270 bridge facility namespace allocation information is recorded in a shared file, DFHBRNSF, to ensure uniqueness of the names. The router regions that share file DFHBRNSF and their associated AOR's form the bridge CICSplex. Multi-bridge CICSplexes can be set up within a larger CICSplex , each router region within a bridge CICSplex sharing the same DFHBRNSF file. The AOR regions of a bridge CICSplex can only be associated with router regions on one bridge CICSplex.

To improve performance, the Link3270 bridge namespace is split into allocation ranges, so that a 'chunk' of names is allocated to each router region, and the DFHBRNSF file is only accessed when a namespace range is allocated or released. Names within the allocated chunks can be reused when keeptimes expire, and chunks may also be reused in other regions, so you may see the same names appearing in different regions, but they are only active in one region at any given time.

Message DFHBR0505 is issued when 90% of the DFHBRNSF names have been allocated and is issued for each percentage point increase in the names being allocated. Message DFHBR0506 is issued for each percentage point reduction in names allocated until below 90%. When no more names are available, message DFHBR0507 is issued, and client application new allocation (or one shot) requests receive a return code of BRIHRC_NO_FREE_NAME.