Generic resource and LU6.1/LU6.2

Although terminals may log on freely using either the generic resource name or the member name this is not the case with LU6.1 and LU6.2 connections which are more restricted in their use of member names.

LU6.2 GR to GR connections

For LU6.2 connections between generic resources the design makes use of LU6.2 autoinstall. Only connections which are intended to issue an ACQUIRE need be defined and these must all have the generic resource name specified as the NETNAME.

Two types of connection are possible.

Since there can only be one generic resource name connection for each partner generic resource it follows that most connections will be member name connections.

EXEC CICS® INQUIRE CONNECTION or CEMT INQUIRE CONNECTION may be used to determine which is the generic resource name and which the member name.

When the first BIND from a different generic resource comes into the SCIP exit (DFHZBLX), a generic resource name connection will be established. If no predefined generic resource name connection exists one will be autoinstalled. Subsequent BINDs coming into DFHZBLX from different members of the same generic resource will cause member name connections to be autoinstalled. A member name connection should never be defined for a member of a different generic resource because this creates the possibility of having two definitions (TCSE's) for the same connected system.

Communications between members of the same generic resource must be by member names only.

Two new bits TCSE_GR and TCSE_GRNAME_CONN have been introduced to indicate the different connection types. They are only valid for LU6.2 connections between generic resources.

The table shows different values of TCTENNAM, TCSESID and TCSEX62N for LU6.2 connections between generic resources, depending on the settings of TCSE_GR and TCSE_GRNAME_CONN:

TCSE_GR
TCSE_GRNAME_CONN
ON
ON
ON
OFF
TCTENNAM
TCSESID
TCSEX62N
GRname
GRname
membername
membername
membername
GRname

LU6.2 GR to non-GR connections

If a single (non-generic resource) system has an LU6.2 connection to a generic resource member it may use either the generic resource name or the member name as the NETNAME.

If the member name is used the initial acquire of the connection must be done by the non-generic resource partner. This means that the generic resource side must not have autoconnect set on. This is because the generic resource partner relies on VTAM® to tell it if it is to known by its member name. VTAM does this by setting a bit which is valid for the first BIND only. Sessions can be acquired by either partner once the SNASVCMG sessions have bound.

For these connections TCSE_GR is always set off and TCSE_GRNAME_CONN has no meaning on both systems. The rule here is that TCSESID always contains the NETNAME (as defined in the RDO connection definition) and TCSEX62N always contains the member name (unique applid). The table illustrates this:

TCSE_GR
TCSE_GRNAME_CONN
RDO_HOSTNAME
OFF
not applicable
GRname
OFF
not applicable
membername
TCTENNAM
TCSESID
TCSEX62N
GRname
GRname
membername
membername
membername
membername

If the generic resource name is to be used, the single system may itself be made into a generic resource allowing it to exploit the design for communications between generic resources. If this is not possible the solution is to use a "hub" or code a generic resource resolution exit to ensure that not more than one member of a generic resource communicates with the single system at any one time using the generic resource name. (The use of "hubs" is described in the CICS Intercommunications Guide).

LU6.1

There is no autoinstall for LU6.1, and so less flexibility is allowed for LU6.1 connections between generic resources. CICS-CICS LU6.1 connections can only communicate by generic resource names and must use a "hub" or a generic resource resolution exit.

TCSE_GR and TCSE_GRNAME_CONN do not apply to LU6.1. For LU6.1 connections with a generic resource the generic resource name is in TCTENNAM and TCSESID and the member name is in TCSEX61N.

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