VARY DRDS command


>>-VARY-- --NET--,--DRDS--,--ID--=--dr_file_name---------------><

Abbreviations

Operand	Abbreviation
VARY	V

Purpose

The VARY DRDS command dynamically reconfigures an NCP or a nonswitched peripheral node. If the physical configuration of a communication controller is changed (for example, a physical unit is moved from one line to another), the NCP that is on the communication controller can be reconfigured without having to generate a new NCP. To use this command, a previously filed set of statements called a dynamic reconfiguration (DR) file must be available before the major node can be reconfigured. For information about dynamic reconfiguration, see the z/OS Communications Server: SNA Network Implementation Guide. For information about creating a DR file, see the z/OS Communications Server: SNA Resource Definition Reference.

Minor nodes that are dynamically added as a result of this command are automatically activated if the DR definition file defines their initial status as active.

Dynamic reconfiguration for an NCP:

For an NCP, this command performs the following functions without regenerating the NCP:

Adds a nonswitched physical unit and its subordinate LUs to a line.
Adds a logical unit to a nonswitched physical unit.
Adds a type 2.1 PU to an NCP ESCON channel.
Adds an independent LU to an NCP ESCON channel.
Passes the GP3174 and RETRIES operands to NCP when dynamically adding a PU.
Moves a nonswitched physical unit and its subordinate LUs from one line to another.
Changes a nonswitched physical unit link station address.
Deletes a nonswitched physical unit and its subordinate LUs from a line.
Deletes a logical unit from a nonswitched physical unit.
Deletes a type 2.1 PU from an NCP ESCON channel.
Deletes an independent LU from an NCP ESCON channel.
Deletes frame relay type 1 PUs. The first PU (the LMI) under a frame relay line cannot be deleted.

The active and inactive requirements for VARY DRDS for an NCP are shown in Table 1.

Table 1. Active and inactive status requirements for VARY DRDS for an NCP
Operation/ resource	Major node	LINE	PU	LU
Add LU	Active	Either	Either	N/A
Add PU	Active	Either	N/A	N/A
Delete PU¹	Active	Either	Inactive	Inactive
Delete LU¹	Active	Either	Either	Inactive
Move PU	Active	Either	Inactive	Inactive
Note: The current state and desired state of the resource must be inactive.

In order to modify a frame relay switching equipment set (FRSESET), you need to know whether the FRSESET was statically or dynamically defined. If you are not sure, you can issue a DISPLAY NET,ID=frseset_name command to find out. Statically means that the FRSESET was included in the NCP generation. Dynamically means that the FRSESET was not included in the NCP generation. Statically and dynamically defined PUs cannot be specified in the same FRSESET; the PUs must be all static or all dynamic.

If the FRSESET was dynamically defined, you can dynamically add and delete PUs from the set. You can delete PUs with the MODIFY DR, VARY DRDS, or VARY ACT,UPDATE=ALL commands. You can add PUs only with the VARY ACT,UPDATE=ADD or VARY ACT,UPDATE=ALL command.

If the FRSESET was statically defined, you can delete PUs from the set, but you cannot add PUs. In practical terms, this means you need to delete the entire FRSESET and then add it back dynamically in order to change. For example, if you have a statically defined FRSESET containing two primary PUs and you want to add two backup PUs, first delete the two primary PUs, deleting the FRSESET itself (because it is empty). Then edit the VTAMLST source file to add the PU definitions for the backup PUs (if necessary) and add the backup PUs to the FRSESET. Then use the VARY ACT command with UPDATE=ADD or UPDATE=ALL. The VARY ACT command causes the FRSESET to be dynamically defined.

If you delete one or more PUs (using MODIFY DR or VARY DRDS) from a statically defined FRSESET without deleting the whole FRSESET, VARY ACT will cause the deleted PUs to be added back, but they will not be part of the FRSESET.

The first PU under a frame relay line (the LMI) cannot be deleted and it cannot be part of an FRSESET.

For more information about how to define frame relay lines, frame relay PUs, and FRSESETs, see the z/OS Communications Server: SNA Resource Definition Reference.

Dynamic reconfiguration for local SNA major nodes:

This command adds and deletes LUs for local SNA major nodes.

The active and inactive requirements for the reconfiguration operations are shown in Table 2.

Table 2. Active and inactive status requirements for VARY DRDS for local SNA major nodes
Operation/ resource	Major node	LINE	PU	LU
Add LU	Active	Either	Either	N/A
Delete LU	Active	Either	Either	Inactive

Operands

ID=dr_file_name: Specifies the name of a dynamic reconfiguration file.