Network node start option list
A VTAM® network node is an APPN node that supports its own users and the end nodes it serves by providing directory and route selection services. Network nodes and their interconnections form an intermediate routing network. The VTAM network node performs searches of the network to locate resources and calculates the best session route from the node of the primary LU to the node of the secondary LU, based on user-specified criteria. Network nodes do not depend on routing definitions such as path, virtual route (VR) and explicit route (ER).
Network nodes can be classified into two basic categories: pure network nodes, which provide APPN function only, and interchange nodes, which provide both APPN and subarea function. An interchange node together with any NCPs it owns is known as a composite network node. In addition, a border node is an APPN network node that interconnects APPN networks having independent topology databases in order to support LU-LU sessions between these networks. When a network node supports the LUs on attached end nodes, it is known as a network node server. Finally, you can configure any network node to act as a central directory server, which builds and maintains a directory of resources throughout the network.
In this section, we show a sample start option list for a pure network node. For information about VTAM in an APPN network, see the z/OS Communications Server: SNA Network Implementation Guide.
The example that follows illustrates the start options for SSCPEA. It is the combination of NODETYPE=NN and HOSTSA not coded that defines this node as a pure APPN network node. Pure network nodes have no subarea function.
The APPNCOS start option specifies the APPN class of service to be used if a requested class of service cannot be found in the topology and routing services class-of-service database. APPNCOS=NONE is the default value.
AUTORTRY specifies whether adjacent node activation will cause a retry of pending automatic logon requests and, if it does, what kinds of adjacent nodes will cause such retries upon activation. AUTORTRY=AUTOCAP (the default value) specifies that such requests are retried only when an adjacent CDRM or an adjacent CP that supports automatic logon is activated.
The AUTOTI start option allows you to specify how often pending automatic logon requests owned by this host are retried. AUTOTI=0 (the default value) specifies that such requests are not retried periodically.
The CINDXSIZ start option specifies the maximum size of the CID and CONVID index tables. The new default value is 8176 bytes.
CPCP=YES enables this node for CP-CP sessions with all adjacent APPN nodes.
The BN start option specifies whether this node is to provide extended border node function. An extended border node supports intermediate network routing, allowing it to support LU-LU sessions that do not terminate in its native network. BN=NO (the default value) specifies that it does not provide that function. The BN start option is meaningful only for nodes that specify NODETYPE=NN.
NETID, SSCPID, and SSCPNAME are required start options. HOSTPU is not required; however, it is recommended if you are using NetView®. The CONFIG start option identifies a unique name of the configuration list to be activated when VTAM starts.
The start option CDSERVR=NO specifies that this network node will not be a central directory server. NO is the default value.
The start option CDSREFER=3 specifies that this network node refers only to the three closest (minimal weight route) central directory servers in the network. For more information about the CDSREFER start option, see the z/OS Communications Server: SNA Resource Definition Reference.
The CONNTYPE start option specifies for a type 2.1 PU whether the connection is established as a LEN connection or attempted as an APPN connection. CONNTYPE=APPN (the default value) specifies that the connection is attempted as an APPN connection.
The DISCNTIM start option specifies the amount of time that VTAM delays deactivation of the SSCP-PU session when there are no outstanding LU-LU session requests. This option is valid only for PU types 2 and 2.1 that have DISCNT=DELAY specified on the PU definition statement. DISCNTIM=15 (the default value) specifies this amount of time as 15 seconds. You can change the value of DISCNTIM with the MODIFY VTAMOPTS command while VTAM is running.
The DLRTCB specifies the largest number of task control blocks (TCBs) used by VTAM for dump/load/restart subtasks and file I/O services. For an APPN network node, you should specify at least 3 for DLRTCB. Two TCBs are needed to process directory services data sets and topology and routing services data sets, and one TCB is needed for other dump/load/restart functions. A value less than 3 can cause VTAM initialization to stall or suspend a session initiation for a function requiring a TCB until a TCB becomes available. The default value for DLRTCB is 32 TCBs.
The DIRSIZE start option helps control the size of the directory services database on a VTAM network node. DIRSIZE specifies the maximum number of dynamic APPN resources that VTAM stores in that database. Once the number specified is reached, storage from the oldest resources is freed and reused. DIRSIZE=0 (the default value) specifies that no limit is enforced for the number of dynamic APPN resources in the directory services database. You can change the value of DIRSIZE with the MODIFY VTAMOPTS command while VTAM is running.
The DIRTIME start option also helps control the size of the directory services database on a VTAM network node. DIRTIME indicates how long an unused resource can remain in the database. The default value is eight days (DIRTIME=8D). You can change the value of DIRTIME with the MODIFY VTAMOPTS command while VTAM is running.
DYNADJCP=YES indicates that adjacent control point (ADJCP) minor nodes are allowed to be created dynamically and placed in the dynamic adjacent control point major node (ISTADJCP).
DYNLU=YES directs VTAM to dynamically allocate host representations of independent LUs during session activation. There is no need for you to predefine your independent LUs if you specify this start option.
The ENHADDR start option specifies whether VTAM can assign element addresses greater than 65535 (high-order addresses) to resources establishing sessions within this subarea. ENHADDR=NO (the default value) indicates that VTAM cannot assign such element addresses.
The HPR start option specifies the level of HPR support provided by VTAM. HPR=RTP indicates that this VTAM network node provides RTP-level HPR support, meaning that it can be the endpoint of an HPR route. RTP is the default HPR value for VTAM network nodes that do not specify HOSTSA.
The HPRPST start option allows you to specify the maximum amount of time that VTAM will continue trying to path-switch before terminating the RTP logical connection. The HPRPST start option value is valid only if the HPR=RTP start option has been coded. In the sample that follows, HPRPST=(30M,1M,20S) sets a limit of 30 minutes for path switch attempts of RTP connections by using low transmission priority classes of service, 1 minute for medium, and 20 seconds for high. The default is 60 seconds for all three priorities.
ROUTERES=1 indicates that it is highly desirable to have this node provide intermediate session routing. During route calculation, this value would be compared with the ROUTERES values of other network nodes.
The start option INITDB specifies whether the directory services and topology and routing services databases are loaded when VTAM is started. INITDB=ALL (the default value) specifies that both databases are loaded at that time. The INITDB start option is meaningful only if the NODETYPE=NN start option is also specified.
The LIMINTCP start option specifies the number of seconds to retain free SNASVCMG sessions on limited resources for the control point. CP SNASVCMG sessions are used for some network management flows. This option affect only network connections defined as limited resources. Network connections are defined as limited resources by specifying LIMRES=YES on the applicable GROUP, LINE, or PU definition statements.
The setting of the SSEARCH start option determines whether the subarea network is searched when search requests from the APPN network arrive at an interchange node. SSEARCH=YES (the default value) indicates that the subarea network is to be searched. Resources in the domain of the interchange node are found even if SSEARCH=NO is specified. You can change the value of SSEARCH with the MODIFY VTAMOPTS command while VTAM is running.
The STRGR start option allows you to rename the generic resources structure. STRGR is a valid start option only on an APPN node (running at least MVS™ V5R1) that is part of a sysplex environment. An MVS coupling facility is also required. STRGR=ISTGENERIC specifies the IBM®-supplied generic resources structure. ISTGENERIC is the default value. Typically, ISTGENERIC is used for the generic resources structure used to run a production environment in a sysplex. For a test environment in the same sysplex, you should define your own name. This name must conform to the restrictions specified in z/OS Communications Server: SNA Resource Definition Reference. For an example, see End node start option list.
The VERIFYCP start option is used to specify whether VTAM is to perform LU-LU session-level verification during activation of LU 6.2 sessions involving control points. VERIFYCP=NONE specifies that no verification of the partner CP's identity is to take place during session activation.
The VFYRED start option specifies whether the node should attempt to perform resource verification reduction. VFYRED=YES indicates that LU 6.2 session initiation requests do not need to be delivered to the target LU. Using the VFYRED start option might allow you to significantly reduce directed verification searches. For more information about the VFYRED start option, see the z/OS Communications Server: SNA Network Implementation Guide and the z/OS Communications Server: SNA Resource Definition Reference.
The VFYREDTI start option specifies the amount of time resource verification reduction is to be performed before the resource's location is verified. VFYREDTI=8H specifies 8 hours as the amount of time resource verification reduction is to be performed. For more information about the VFYREDTI start option, see the z/OS Communications Server: SNA Network Implementation Guide and the z/OS Communications Server: SNA Resource Definition Reference.
The TRACE,TYPE=VTAM,OPT=ALL start option indicates that all VTAM internal trace options should be started. CMIP, has been added by VTAM V4R3. It generates entries that help you determine whether a CMIP problem is in VTAM or in a CMIP application program. You can explicitly enable the CMIP trace option by specifying OPT=CMIP. Specifying OPT=ALL automatically enables the CMIP trace option, along with all other VTAM internal trace options. Another new VTAM internal trace option, The HPR VIT option generates entries that help you isolate problems related to High-Performance Routing. You can explicitly enable the HPR trace option by specifying OPT=HPR. Specifying OPT=ALL automatically enables the HPR trace option, along with all other VTAM internal trace options.
The TRACE,TYPE=BUF,ID=ISTNOTIF start option specifies that a VTAM buffer trace is to be started for notification services. The buffer trace will trace event notification activity between the VTAM topology agent and notification services of CMIP services. Make sure that GTF with the TRACE=USR option is active before starting this trace.
* =====> BEGINNING OF DATA SET ATCSTREA
**********************************************************************
* NAME: ATCSTREA (VTAM START LIST FOR HOST EA)
**********************************************************************
APPNCOS=NONE, NO BACKUP APPN CLASS OF SERVICE X
SSCPID=4, HOST ID X
SSCPNAME=SSCPEA HOST NAME X
CONFIG=EA, START CONFIG LIST X
NETID=NETA, IN NETA X
NODETYPE=NN, PURE APPN NN, NO SUBAREA CAPABILITIES X
AUTORTRY=AUTOCAP, AUTOLOGON RETRY ACTIVATION VALUE X
AUTOTI=0, NO PERIODIC AUTOLOGON RETRIES X
BN=NO, NO EXTENDED BORDER NODE FUNCTION X
CDSERVR=NO, NOT A CENTRAL DIRECTORY SERVER X
CDSREFER=3, REFER TO 3 NEAREST CENTRAL DIRECTORY SERVERS X
CINDXSIZ=8176, CIT & CONVT INDEX TABLE SIZE X
CONNTYPE=APPN, APPN CONNECTIONS FOR APPN PUS X
CPCP=YES, CP-CP SESSION CAPABLE X
DIRSIZE=0, NO UPPER LIMIT ON DYNAMIC APPN RESOURCES X
DIRTIME=8D, AFTER 8 DAYS UNUSED APPN RESOURCES DELETED X
DISCNTIM=15, SSCP-PU DEACTIVATION DELAY X
DLRTCB=32, TCBS FOR DUMP/LOAD/RESTART AND FILE I/O X
DYNADJCP=YES, DYNAMIC ADJACENT CP X
DYNLU=YES, DYNAMIC LU X
ENHADDR=NO, NO HIGH-ORDER ELEMENT ADDRESSES FOR PLUS X
HPR=RTP, RTP-LEVEL HPR SUPPORT X
HPRPST=(30M,1M,20S), HPR PATH SWITCH TIMER VALUES X
INITDB=ALL, LOAD APPN DATABASES AT VTAM START X
LIMINTCP=29, CP SNASVCMG LIMITED RESOURCE INTERVAL X
SSEARCH=YES, SEARCH IN SUBAREA NETWORK X
STRGR=ISTGENERIC, GENERIC RESOURCE STRUCTURE NAME X
VERIFYCP=NONE, VERIFY CP (DEFAULT) X
VFYRED=YES, LU 6.2 VERIFICATION REDUCTION X
VFYREDTI=8H, VERIFICATION REDUCTION TIMER VALUE X
TRACE, X
TYPE=VTAM, X
OPT=ALL, ALL INTERNAL TRACE TYPES STARTED X
SIZE=200, START VIT X
TRACE, X
TYPE=BUF, X
ID=ISTNOTIF, START BUFFER TRACE FOR NOTIFICATION SERVICES X
AMOUNT=FULL, REQUIRED FOR ISTNOTIF X
CRPLBUF=(200), PAGEABLE RPL POOL X
LFBUF=(100,,10,,10,33), FIXED LARGE BUFFER POOL X
LPBUF=(64,,4,,4,22), PAGEABLE LARGE BUFFER POOL X
SFBUF=(60), FIXED SMALL BUFFER POOL X
SPBUF=(32), PAGEABLE SMALL BUFFER POOL X
ROUTERES=1 ROUTE ADDITION RESISTANCE VALUE
* =====> END OF DATA SET ATCSTREA