HP OpenVMS Systems Documentation
OpenVMS System Management Utilities Reference Manual
When the database reaches the node limit, no more nodes are added to the database when your local node receives service announcement messages. You can ensure that the node limit is not reached by using the /USER_GROUPS qualifier to restrict access from the local node to other service nodes on the network.
If you do not specify either the /NODE_LIMIT=value or /NONODE_LIMIT qualifier, the default is no limit. A value of 0 indicates no limit.
/QUEUE_LIMIT=valueSets a limit on the number of entries (incoming LAT connections only, not outgoing printer connections) that are queued on the system. The queue limit value can range from 0 to 200, with a default of 24. A value of 0 indicates that no queuing is allowed.
/RETRANSMIT_LIMIT[=count]Specifies the number of times your local node repeats transmission of a message to a service node after a transmission fails. If the transmission is still unsuccessful after these attempts, the virtual circuit between your local node and the service node terminates, along with all sessions associated with the virtual circuit.
Use this qualifier only if your node allows outgoing connections (/CONNECTIONS=OUTGOING_ONLY or /CONNECTIONS=BOTH).
Specify a value in the range of 4 to 120. The default is 8. The value you choose depends on the type of physical link used for your network, as well as the amount of traffic on the network. See your network manager for a suggested value. You cannot change this value if active or pending connections exist.
/NOSERVICE_RESPONDERSpecifies whether your system responds to special LAT multicast messages that request service information. Some terminal servers do not have their own service and node database. When a user on such a terminal server requests a connection to a service, the server sends a LAT multicast message requesting names of nodes that offer the requested service. Service responder nodes reply with the requested information.
If you specify /SERVICE_RESPONDER, your system responds to the special LAT multicast messages. (If you specify /NOSERVICE_RESPONDER, your system does not respond to those messages.) Compaq recommends that you set up only one or two nodes in the LAN as service responder nodes. The nodes should have the largest databases in the LAN. Use this option only if your node allows outgoing connections (/CONNECTIONS=OUTGOING_ONLY or /CONNECTIONS=BOTH).
If you do not specify either the /SERVICE_RESPONDER or /NOSERVICE_RESPONDER qualifier, the default is that your system will not respond to the special LAT multicast messages.
/SESSION_LIMIT=optionSpecifies the maximum number of simultaneous sessions across all local-access ports. This limit does not affect the use of dedicated and application ports. It affects interactive port creation only, limiting the amount of resources consumed by interactive users creating new sessions.
The options for the /SESSION_LIMIT qualifier are:
If the limit is reached, interactive users cannot create new sessions. In this case, increase the session limit or disconnect any connections that are no longer being used.
Specify a value in the range of 0 to 255. Specifying 0 leaves no limit on the number of sessions that can be created. To prevent sessions from being created, use the /CONNECTIONS qualifier.
Not specify the /SESSION_LIMIT qualifier causes no limit on the number of incoming and outgoing sessions. This is the default.
/STATE=optionSpecifies whether LAT connections are allowed. The three options for STATE are:
If you do not specify the /STATE=option qualifier, the default is that the LAT port driver and LAT protocol software on your node will be started (ON).
/UNIT_NUMBER_MAXIMUM=valueSpecifies the maximum unit number for a LAT device. For example, if you specify 140, then LTA140: will be the device with the highest unit number. Specify a value that is high enough to accommodate all devices that may be in use simultaneously. When the number of devices in use exceeds the value you specify, the system gives certain LAT devices unit numbers that exceed your maximum.
Also note the following points:
The range of maximum unit numbers is 99 to 9999. The default is 9999. Note that each time you specify the /UNIT_NUMBER_MAXIMUM qualifier, the LTA device seed value is reset to approximately half of the newly specified maximum unit number.
/USER_GROUPS=option[,...]Restricts access (from the local node) to service nodes in the network that belong to the specified groups. Your local node can access only those service nodes associated with the user groups specified. The /USER_GROUPS qualifier also serves to limit the number of nodes stored in your node's node database. (The local node only stores information about the nodes and services that belong to at least one of the specified user groups.) By default, all LAT service nodes belong to group 0.
This qualifier affects your local node when outgoing connections are enabled (/CONNECTIONS=OUTGOING_ONLY or /CONNECTIONS=BOTH).
Use the SHOW NODE command for a list of the user groups (service groups) enabled for your node.
The /USER_GROUPS qualifier has several options. For each option described here, you can use two ways to specify more than one group:
The available options are as follows:
The SET NODE command, which is typically executed in the site-specific LAT configuration command procedure, LAT$SYSTARTUP.COM, allows you to specify such characteristics as:
LATCP> SET NODE DUKE /IDENT="NODE DUKE, SALES VMSCLUSTER"
This command specifies node name DUKE for your local node. The identification string "NODE DUKE, SALES VMSCLUSTER" is multicast from node DUKE.
LATCP> SET NODE /MULTICAST_TIMER=50 /GROUPS=(ENABLE=(1-3,8,11),DISABLE=5)
This command causes your local node to send multicast messages every 50 seconds to announce DUKE's services to terminal servers. The command also enables groups 1, 2, 3, 8, and 11 for access to the local node, and it disables group 5 from accessing the local node. Group 5 had been previously enabled.
LATCP> SET NODE /CONNECTIONS=BOTH /USER_GROUPS=(ENABLE=(24,121-127),DISABLE=0)
This command sets up your local node to allow both incoming and outgoing connections. Users on your local node can access those service nodes belonging to user groups 24 and 121 through 127. Users cannot access service nodes in user group 0.
LATCP> SET NODE /CIRCUIT_TIMER=80 /KEEPALIVE_TIMER=20 - _LATCP> /RETRANSMIT_LIMIT=20 /CONNECTIONS=BOTH /MULTICAST_TIMER=60- _LATCP> /GROUPS=(DISABLE=0,ENABLE=73) /SESSION_LIMIT=(OUTGOING=10,INCOMING=0)
This command sets many characteristics at once for node DUKE.
Associates a logical port on the local node with a remote port on a terminal server that supports a device. Alternatively, it associates a logical port on the local node with a specific service. The service can be offered by a terminal server or associated with one or more dedicated ports on a remote LAT service node.
You must have OPER privilege to use this command.
SET PORT port-name
port-nameSpecifies the name of the port. A port name must be in the form LTAn:, where n is a unique number from 1 to 9999.
You cannot use the CREATE PORT and SET PORT commands, along with the DCL command SET TERMINAL, to change the characteristics of a DECserver port unless there is an existing LAT connection to that DECserver.
/APPLICATIONSpecifies that a port on the local node is an application port, logically associated with a port on a terminal server or a dedicated port on another LAT service node. The terminal server port supports a device (for example, a printer). If the port is used to support a printer, the print queue is established in a startup command procedure. Refer to the OpenVMS System Manager's Manual for a description of configuring remote printers on a terminal server.
If you do not specify a port type, the default port type is APPLICATION.
/DEDICATEDSpecifies that a logical port on your local node is dedicated to an application service. The /DEDICATED qualifier requires the /SERVICE qualifier.
- Create the service by specifying the CREATE SERVICE/APPLICATION command and then define the dedicated port by specifying the CREATE PORT/DEDICATED command. You can include these commands in LAT$SYSTARTUP.COM.
- Associate the dedicated ports with the service by specifying the SET PORT/DEDICATED/SERVICE command.
- Start the application program. Within the program, allocate dedicated ports with the same name as those defined in LAT$SYSTARTUP.COM.
/LIMITEDSpecifies that a logical port on your local node is limited to a service in the same way a port created using the /DEDICATED qualifier is dedicated to an application service. The difference is that ports created using the /LIMITED qualifier are under the control of the system login image (LOGINOUT.EXE) instead of an application program (a user who connects to a limited service and is assigned to a limited port receives the Username: prompt).
Using the /LIMITED qualifier, you can create a limited number of ports and map them to a specific service offered by the host system. If users are logged in to all of the limited ports for the service, no more connections are allowed to that service (terminal server users receive a "service in use" message).
/NOLOG (default)Specifies whether LATCP displays a message confirming that the port's characteristics were modified. If you do not specify the /LOG or /NOLOG qualifier, the default is that no message will be displayed.
/NODE=remote-node-nameSpecifies the name of a terminal server (or a remote node that supports outgoing connections) to be logically associated with the specified application port on your node. The server supports a remote device. Note that you can set up an application port on your local node and associate the port with a dedicated port on a remote LAT service node. The remote port is dedicated to an application service.
/PASSWORD=remote-passwordSpecifies the password required to access a remote service that is logically associated with the specified application port.
/PORT=remote-port-nameSpecifies the name of the remote port on a terminal server that supports a remote device, or specifies the name of a remote port dedicated to an application service on a remote LAT service node. In either case, the remote port is logically associated with the specified application port on your local node.
/NOQUEUEDSpecifies queued or nonqueued access to the server port. A queued or nonqueued request is accepted by a terminal server if a remote port is free. If the remote port is busy and queuing is enabled on the terminal server, then the server queues the remote request. If you do not want your remote requests to be queued on the server, specify /NOQUEUED.
Not specifying either the /QUEUED or /NOQUEUED qualifier results in queued access to the server port. This is the default.
/SERVICE=service-nameSpecifies either of the following names:
- The name of the remote service offered at a terminal server port that will be associated with the specified application port (/APPLICATION) on the local node
- A service name for an application program being offered on a dedicated port (/DEDICATED) on a LAT service node
To specify the name of a remote service offered at a terminal server port, use the /NODE and /SERVICE qualifiers. To specify a particular port for a service, use the /NODE, /PORT, and /SERVICE qualifiers. Ask the terminal server manager for these names.
To name a service for a particular application program to be offered locally on a dedicated port, use the /DEDICATED and /SERVICE qualifiers. (The service must have been created with the CREATE SERVICE command.) Assign only one service to a dedicated port, but note that several ports can have the same service assigned.
The SET PORT command associates an application port on your local node with a port or service on a terminal server.
To create a port, use one of the following methods:
- Interactively enter the CREATE PORT command.
- Run a program that creates ports.
When you associate an application port with a service on a terminal server, you allow access to any of the ports (printers) represented by that service (see Examples 1 and 2). Note that the application port must have been created with the CREATE PORT/APPLICATION command.
The SET PORT command can also associate a dedicated port on the local node with an application service offered locally. The service must already exist (see Example 3). Note that you must use the /DEDICATED and /SERVICE qualifiers.
The SET PORT command can also associate an application port on your local node with an application service associated with one or more dedicated ports on a remote LAT service node. This service is offered to users on terminal servers or on nodes that support outgoing connections (see Example 4). Note that the dedicated port must have been created with the CREATE PORT/DEDICATED command.
You can also set up the port as a limited port, using the /LIMITED qualifier.
See the examples for the SHOW PORT command for displays that reflect the changes made by the following SET PORT command examples.
LATCP> SET PORT LTA22: /APPLICATION /NODE=TS33EW /PORT=LN02
This command sets up port LTA22: as an application port to be associated with the port named LN02 on the terminal server named TS33EW. This command associates port LTA22: with a specific printer on the server. In the next example, the SET PORT command associates a port with a set of printers (designated by the service name PRINTER) on a terminal server.
LATCP> SET PORT LTA19: /APPLICATION /NODE=TLAT1 /SERVICE=PRINTER /QUEUED
This command shows how to associate a local logical port with a service (several printers) on a terminal server. The command associates the application port LTA19: with the service PRINTER on terminal server TLAT1. The service PRINTER can be associated with one or more ports on TLAT1. The /QUEUED qualifier specifies that the server offering the service PRINTER can queue the remote connection request if all ports offering the service are in use. Refer to the description of print operations in the OpenVMS System Manager's Manual for information about setting up print queues.
LATCP> SET PORT LTA21: /DEDICATED /SERVICE=GRAPHICS
This command specifies that the application port LTA21: on the local service node offers the service GRAPHICS to users on terminal servers or on nodes that support outgoing connections. GRAPHICS is a particular utility or application program.
LATCP> SET PORT MAIL_PORT /SERVICE=MAIL/NODE=RMNODE
This command associates the port whose logical name is MAIL_PORT with the dedicated service MAIL on remote node RMNODE. The port logically named MAIL_PORT was created with the CREATE PORT command (see Example 3 in the discussion of the CREATE PORT command). The logical name could also have been created with the DCL command ASSIGN or DEFINE. On node RMNODE, a port must be dedicated to the service MAIL by using the SET PORT port-name /DEDICATED/SERVICE=MAIL command.
$ LCP :== $LATCP $ LCP CREATE SERVICE/LIMITED ONLY_ONE $ (U>(LCP CREATE PORT/LIMITED LTA1234:) $ (U>(LCP SET PORT LTA1234: /SERVICE=ONLY_ONE)
This series of commands, which includes the SET PORT command, creates a limited service that allows only one user to log in to the system through that service. When a user connects to service ONLY_ONE by responding to the terminal server prompt (Local>), the user is assigned port LTA1234 and then prompted for the user name. Any user who attempts to connect to the same service while LTA1234 has a user logged in receives the "service in use" message.