HP OpenVMS Systems Documentation
HP OpenVMS System Management Utilities Reference Manual
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. For a description of configuring remote printers on a terminal server, see the HP OpenVMS System Manager's Manual.
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. For information about setting up print queues, see the description of print operations in the HP OpenVMS System Manager's Manual.
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.
Dynamically changes the characteristics of a locally offered service. You must have OPER privilege to use this command.
SET SERVICE [service-name]
service-nameSpecifies the service whose characteristics are to be modified. If a service name is omitted, the default service name is the name of the local node you defined by using the SET NODE command.
/APPLICATIONSets up the service as an application service. An application service offers a specific application on the service node rather than all of the resources on the service node. Define a dedicated port for the service by using the CREATE PORT and SET PORT commands.
/NOCONNECTIONSSpecifies whether a service offered by an OpenVMS system accepts incoming connections. If you use the /NOCONNECTIONS qualifier to disable incoming connections, users cannot connect to that service and receive instead the error message "service is disabled."
By default, a service accepts incoming connections (/CONNECTIONS).
/IDENTIFICATION[="identification-string"]Describes and identifies a service. Service nodes include the identification string in service announcements. A service node announces its services at regular intervals established with the SET NODE command. Entering the LATCP command SHOW NODE or the DECserver command SHOW NODE generates a display that includes this identification string.
By default, the identification string is the translation of SYS$ANNOUNCE. A service node announces its services at regular intervals established with the SET NODE command.
You cannot specify more than 64 ASCII characters in an identification string (a SYS$ANNOUNCE longer than that will be truncated to the first 64 characters). Enclose the string in quotation marks (" ").
/LIMITEDSpecifies that the service is a limited service, using devices assigned the limited characteristic and associated with (mapped to) this limited service. This qualifier is used in conjunction with the SET PORT /LIMITED command (see Example 2).
/NOLOG (default)Specifies whether or not LATCP displays a message confirming that the command was executed. If you do not specify the /LOG or /NOLOG qualifier, the default is that no message will be displayed.
/NOQUEUEDSpecifies whether a locally offered limited (/LIMITED) or application (/DEDICATED) service is allowed to have queued connections when all ports are busy (the default). If you specify /NOQUEUED, incoming connections will be rejected if all ports are busy.
/NOSTATIC_RATINGEnables or disables dynamic service ratings. A dynamic service rating means that a LAT algorithm calculates the availability of a service dynamically, based on the overall level of activity of the node that offers the service and the amount of memory. When a terminal server or node requests a connection to a service that is offered on two or more service nodes, the requesting node selects the service node with the highest (most favorable) service rating. This selection process is called load balancing.
The dynamic service rating, which is the default, is usually adequate for efficient load balancing on the LAT network. However, when necessary, you can use the /STATIC_RATING qualifier to disable dynamic service ratings so that you can specify a static (fixed) rating. That static rating value does not change until the dynamic service rating is reenabled.
Use the static rating to direct users away from or toward your node temporarily. Static ratings range from 0 to 255. Specify a low value to make the local service node less likely to be used; specify a high value to make the local service node more likely to be used.
If you do not specify either the /STATIC_RATING or /NOSTATIC_RATING qualifier, the default is that the LAT software uses the dynamic service rating.
Limited and application services do not rely exclusively on the dynamically calculated service rating. Instead, they use a portion of the dynamic rating based on how many ports are available for the service. For example, if a limited service has 50 percent of its ports available, the dynamic service rating will be scaled, halved, and then added to 105. When ports are available, the rating will always be above the value 105.
When all ports for a limited or application service are in use, the rating will be based on the scaled dynamic rating and the number of free queue slots on the local node. The rating will always be less then 90.
This rating procedure for limited and application services follows the terminal server rating algorithm for services and available ports that the service offers, while at the same time taking into account the availability of the node (which is the factor used to calculate the dynamic rating).
If your system is licensed for a specific number of units (where only a fixed number of users can log in to the system regardless of how the login limit is set), then all dynamic ratings become 0 when all OpenVMS license units have been consumed. (This forces all node service ratings to the lowest possible value when logins are not possible because all OpenVMS license units have been consumed.)
Note that the LAT software transmits a service announcement message when a user logs in to or out of the system. This allows the system to more quickly provide information about service rating changes that result from a login or logout operation.
The SET SERVICE command dynamically changes the characteristics of a service that you created previously (by interactively entering the CREATE SERVICE command or by running a program that created services).
LATCP> SET SERVICE SALES /IDENT="SALES FORCE TIMESHARING SERVICES"
This command specifies a new identification string, "SALES FORCE TIMESHARING SERVICES", for the service SALES. This string is announced with the service SALES in the multicast messages sent by a service node.
$ LCP :== $LATCP $ LCP SET SERVICE/LIMITED ONLY_ONE $ LCP CREATE PORT/LIMITED LTA1234: $ LCP SET PORT LTA1234: /SERVICE=ONLY_ONE
This series of commands changes an existing service to 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.