MODIFY DR command


Delete a logical unit from a physical unit, or a physical unit from a line:

>>-MODIFY-- --procname--,--DR--,--TYPE--=--DELETE--------------->

>--+-,--ID--=--lu_name--,--FROM--=--pu_name---+----------------><
   '-,--ID--=--pu_name--,--FROM--=--line_name-'


Move a physical unit:

>>-MODIFY-- --procname--,--DR--,--TYPE--=--MOVE----------------->

>--,--ID--=--pu_name--,--FROM--=--line_name--------------------->

                        .-,--ACTIVATE--=--NO------.   
>--,--TO--=--line_name--+-------------------------+------------->
                        '-,--ACTIVATE--=--+-NO--+-'   
                                          '-YES-'     

>--+----------------------------------+------------------------><
   '-,--ADDR--=--link_station_address-'

Abbreviations

Operand	Abbreviation
MODIFY	F
ACTIVATE=NO	ACT=NO
ACTIVATE=YES	ACT=YES

Purpose

The MODIFY DR (dynamic reconfiguration) command dynamically reconfigures an NCP or a local peripheral node. You can use this command to delete or move type 1, 2, and 2.1 PUs along with their associated LUs, or to delete LUs.

See the z/OS Communications Server: SNA Network Implementation Guide for information about dynamically reconfiguring VTAM® peripheral nodes and for information about dynamic NCP reconfiguration.

The MODIFY DR command cannot dynamically add a physical unit or logical unit. To add a physical or logical unit, use the VARY DRDS command with a DR file or use the VARY ACT command with the UPDATE operand. You can also use the VARY DRDS command or the VARY ACT command with the UPDATE operand to perform the same functions as the MODIFY DR command.

Note: See the MODIFY ALSLIST command for information about how to update the list of PUs (adjacent link stations) associated with an independent LU.

Dynamic reconfiguration for an NCP:

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

Moves a nonswitched PU and its subordinate LUs from one line to another
Changes a nonswitched PU link station address
Deletes a nonswitched PU and its subordinate LUs from a line
Deletes an LU from a nonswitched PU
Deletes a type 2.1 PU on an NCP ESCON channel
Deletes an independent LU on an NCP ESCON channel
Deletes frame relay type 1 PUs

An NCP must be active and must be capable of dynamic reconfiguration before it can be dynamically reconfigured. The active and inactive requirements for the reconfiguration operations are shown in Table 1 and Table 2.

Table 1. Active and inactive status requirements for MODIFY DR for an NCP
Operation/ resource	Major node	LINE	PU	LU
Delete PU	Active	Either	Inactive	Inactive
Delete LU	Active	Either	Either	Inactive
Move PU	Active	Either	Inactive	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, follow these steps:

Delete the two primary PUs, deleting the FRSESET itself (because it is empty).
Edit the VTAMLST source file to add the PU definitions for the backup PUs and add the backup PUs to the FRSESET.
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 peripheral nodes:

For a VTAM local peripheral node, this command performs the following functions:

Deletes a logical unit from a VTAM nonswitched peripheral node. This is possible only for local SNA major nodes. The MODIFY DR command cannot move resources in a VTAM peripheral node, and it cannot delete physical units or lines in a VTAM peripheral node.
Removes a PU from an independent LU's adjacent link station list.
Note: You cannot use MODIFY DR to move an independent LU.

Table 2. Active and inactive status requirements for MODIFY DR for local peripheral nodes
Operation/ resource	Major node	LINE	PU	LU
Delete LU	N/A	Either	Either	Inactive

Operands

procname

The procedure name for the command. If procname in the START command was specified as startname.ident, where startname is the VTAM start procedure and ident is the optional identifier, either startname.ident or ident can be specified for procname.

If procname in the START command was startname, startname must be specified for procname.

ACTIVATE

Applies only if TYPE=MOVE. It specifies whether the physical unit and its associated logical units are activated automatically after a successful move.

ACTIVATE=YES

VTAM activates the physical unit and its associated logical units after the move completes successfully. This is equivalent to entering VARY ACT,ID=pu_name,SCOPE=ONLY after the MODIFY DR,ID=pu_name,TYPE=MOVE command has successfully completed.

Note:

If the line to which the PU is being moved is inactive before the move, ACTIVATE=YES does not activate the line.
If the system programmer has defined the initial status of a logical unit subordinate to the moved physical unit (ISTATUS) as inactive, ACTIVATE=YES does not activate the logical unit. The logical unit must be explicitly activated.
If the line to which the PU is being moved is active, and the PU's ISTATUS is active, the PU and associated LUs are activated even if ACTIVATE=YES is not specified.

ACTIVATE=NO

VTAM does not activate the physical unit and its associated logical units after the move completes.

ADDR=link_station_address

Applies only if TYPE=MOVE. It specifies the physical unit's link station address. Using this operand, you can change the physical unit's link station address.

To change the address, use both the TO and FROM operands. The address value must be a 2-digit hexadecimal number that is unique for each physical unit on the same line.

You can use the ADDR operand to change a physical unit's SDLC link station address regardless of whether the physical unit is being moved to a new line. (It is acceptable to code the same line on the TO and FROM operands associated with a TYPE=MOVE command.)

If you use the ADDR operand to assign link station addresses, be careful when using an address that a resource previously used. NCP is not informed of dynamic moves or additions until the resource is activated; therefore, activate resources in the order in which the dynamic reconfiguration requests were made.

FROM

Specifies the line name or physical unit in the dynamic reconfiguration.

FROM=line_name

If TYPE=MOVE, identifies the line from which the physical unit and its subordinate LUs are to be moved.

If TYPE=DELETE, identifies the name of the line from which the physical unit and all associated logical units are to be deleted.

The line must be nonswitched. The line can be active or inactive.

FROM=pu_name

Identifies the physical unit from which the logical units identified in the ID operand are to be deleted. The physical unit must be nonswitched.

If ID specifies an independent logical unit, the logical unit must not have any session over the physical unit (adjacent link station) named in the FROM operand.

ID

Specifies the physical unit or logical unit in the dynamic reconfiguration. When TYPE=DELETE is specified, the name can be a network-qualified name.

ID=pu_name: Identifies the physical unit to be deleted or moved (as specified in the TYPE operand) and its associated logical units. The physical unit must be inactive and nonswitched.
ID=lu_name: Applies only if TYPE=DELETE. It identifies the logical unit to be deleted. The logical unit must be inactive and under a nonswitched physical unit. If the specified logical unit is an independent LU, it must not have any session over the physical unit (adjacent link station) specified in the FROM operand.

TO=line_name

Applies only if TYPE=MOVE. It identifies the line to which the physical unit and its associated logical units are to be moved. The line must be attached to the same NCP as the physical unit and be nonswitched. The line can be active or inactive.

This operand is required with TYPE=MOVE.

TYPE

Specifies the type of dynamic reconfiguration to be performed.

The MODIFY DR command is valid only for nonswitched PUs and LUs and type 2.1 PUs on ESCON channels. MODIFY DR is not supported for cross-domain resources. You cannot move or delete a PU that has PUDR=NO coded in its NCP definition, and you cannot delete a dependent LU that has LUDR=NO coded in its NCP definition.

The MODIFY DR command can be used to delete PUs from an independent LU's adjacent link station list if the independent LU has no active sessions over the PU; however, the MODIFY ALSLIST command is recommended for adding and deleting PUs from an adjacent link station list.

TYPE=MOVE: Moves the physical unit identified in the ID operand, and all logical units associated with the physical unit, from the line identified in the FROM operand to the line identified in the TO operand. You can move a physical unit from one line to another only if both lines are attached to the same NCP.
TYPE=DELETE: Deletes the physical unit identified in the ID operand and all logical units associated with the physical unit from the line identified in the FROM operand, or deletes the logical unit identified in the ID operand from its physical unit identified in the FROM operand.