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HP OpenVMS System Management Utilities Reference
Manual
The default device seed value is approximately half of the maximum unit
number (which you set by using the /UNIT_NUMBER_MAXIMUM qualifier).
Interactive LAT ports, and those created with the CREATE PORT/LOGICAL
command, are assigned unit numbers beginning with the specified device
seed value and continuing up to the maximum unit number. When the
maximum unit number is reached, the port is assigned the next available
unit number beginning at the bottom of the range (LTA1:).
Note that each time you specify the /UNIT_NUMBER_MAXIMUM qualifier, the
device seed value is reset to approximately half of the newly specified
maximum unit number.
/FORWARD_SESSION_LIMIT[=value]
Controls the number of sessions (a value within a range from 16 to 255)
allowed on each outgoing connection. By default, 16 sessions are
allowed on an outgoing connection, which means that 16 individual
processes can direct the DCL command SET HOST/LAT to the same remote
node.
You must increase the value for the /FORWARD_SESSION_LIMIT qualifier if
a user on your system enters the command SET HOST/LAT and receives an
error message indicating that the session limit for the LAT circuit has
been reached (%LAT-F-VCSESLIM). Note, however, that you can change this
value only when no connections exist.
/GROUPS=option[,...]
Gives the listed groups access to services offered on your local node
or prevents the listed groups from accessing services offered on your
local node, depending on the options used.
A network manager organizes terminal server nodes into groups based on
the number of terminal server nodes in the LAT network. Groups
subdivide the LAT network, limiting the number of terminal server nodes
that can connect with a given service node.
As many as 256 groups, numbered 0 to 255, can be in the LAT network. By
default, all terminal server nodes and nodes supporting outgoing
connections belong to group 0. If you enter one group code, you can
omit the parentheses. Use the SHOW NODE command for a list of the
groups enabled for your service node.
The /GROUPS qualifier has several options. For each option described,
you can specify more than one group by:
- Listing them separated by commas
- Specifying a range
The available options are:
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ENABLE=
group-code[,...]
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Gives the listed groups access to your service node.
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DISABLE=
group-code[,...]
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Prevents the listed groups from accessing your service node. The listed
groups had been enabled previously for access to your node.
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ENABLE=
group-code[,...],
DISABLE=
group-code[,...]
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This option lets you enable certain groups and disable other groups in
one command line: gives access to the groups listed with the ENABLE
option and removes access from the groups listed with the DISABLE
option. Enclose both ENABLE and DISABLE in parentheses; for example,
/GROUP=(ENABLE=(10,12),
DISABLE=(1-30)).
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Example 2 shows how to specify the /GROUPS qualifier with the SET NODE
command.
/IDENTIFICATION[="identification-string"]
Describes and identifies a node. 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$ANNOUNCE.
You cannot specify more than 64 ASCII characters in an identification
string (a SYS$ANNOUNCE longer than that will be truncated to the first
64 characters). Enclose the string in quotation marks (" ").
/KEEPALIVE_TIMER[=secs]
Controls the maximum interval, in seconds, between idle run messages
sent by your local node to another service node to which it has a LAT
connection. Your node sends these messages when no other traffic is
being generated over the virtual circuit. If the service node
acknowledges these messages, your node will continue to monitor the
status of the circuit. If your node does not receive acknowledgment, it
responds as if the circuit is down.
Use this qualifier only if your node allows outgoing connections
(/CONNECTIONS=OUTGOING_ONLY or /CONNECTIONS=BOTH).
The default value is 20. HP recommends this value for normal LAN
environments. For a heavily loaded LAN, consider using a higher value.
Set the timer in the range of 10 to 255. For applications that require
quick notification and possible failover of a service node failure, use
a lower value. You cannot change this value if active or pending
connections exist.
/LARGE_BUFFER
/NOLARGE_BUFFER
Controls whether the LAT software uses large buffers while managing
communications between OpenVMS systems (the default).
If you must use the /NOLARGE_BUFFER qualifier (for example, to limit
packet sizes to be no larger than the Ethernet maximum), HP recommends
that you specify this command after all logical LAT links have been
created and before the LAT node has been turned on. For example, note
the following commands in LAT$SYSTARTUP.COM:
$!
$! Create each logical LAT link with a unique name and
$! unique LAN address (forced with /NODECNET).
$!
$ LCP CREATE LINK FDDI_1 /DEVICE=FCA0 /NODECNET
$ LCP CREATE LINK FDDI_2 /DEVICE=FCB0 /NODECNET
$!
$! Don't use large buffer support (force packet
$! sizes to be no larger than what Ethernet can
$! support).
$!
$ LCP SET NODE /NOLARGE_BUFFER
$!
$! Turn on the LAT protocol.
$!
$ LCP SET NODE /STATE=ON
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/LOG
/NOLOG (default)
Specifies whether LATCP displays a message confirming that the node's
characteristics were modified. If you do not specify the /LOG or /NOLOG
qualifier, the default is that no message will be displayed.
/MULTICAST_TIMER[=secs]
Specifies the time, in seconds, between multicast messages sent by
a service node. A multicast message announces the services offered by a
service node. The minimum value is 10 seconds; the maximum is 180
seconds. The default value is 60.
/NODE_LIMIT=value
/NONODE_LIMIT
Specifies the maximum number of service nodes that your local node can
store in its service and node database.
Use this qualifier only if your node allows outgoing connections
(/CONNECTIONS=OUTGOING_ONLY or /CONNECTIONS=BOTH).
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=value
Sets 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.
/SERVICE_RESPONDER
/NOSERVICE_RESPONDER
Specifies 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.) HP 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=option
Specifies 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:
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INCOMING=
value
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Sets the session limit for incoming connections only. The default is no
limit (a value of 0).
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OUTGOING=
value
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Sets the session limit for outgoing connections only. The default is no
limit (a value of 0).
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INCOMING=
value,OUTGOING=
value
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Sets the limit for both outgoing and incoming connections. Enclose both
options in parentheses; for example, /SESSION_LIMIT=(INCOMING=20,
OUTGOING=25).
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- A high limit allows users to have more sessions but increases
memory utilization on your local node.
- A low limit decreases memory utilization on your local node but
limits user access to services on the network.
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=option
Specifies whether LAT connections are allowed. The three options for
STATE are:
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ON
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Starts the LAT port driver (and LAT protocol software) on your node.
HP strongly recommends that the LATCP command SET NODE/STATE=ON be
executed before any LTA application or dedicated ports are created (use
the format provided in SYS$MANAGER:LAT$SYSTARTUP.TEMPLATE) for two
reasons:
- It ensures that LTDRIVER will delete any leftover LTA devices that
have a reference count of 0 and are explicitly marked for deletion
(using the $DASSGN system service or the LATCP command DELETE PORT, for
example). Because every LATCP management port (LATCP$MGMT_PORT) that
was created by the previous LATCP invocation is deleted, no conflicts
result with the LAT application ports or newly created dedicated ports.
- The deletion of leftover LTA devices with a reference count of 0
minimizes the use of nonpaged pool memory.
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OFF
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Stops the LAT port driver (and LAT protocol software) on your node. Any
existing LAT connections are aborted. Any characteristics that you
changed or set with LATCP are lost.
To start the LAT protocol on your node again, invoke
LAT$STARTUP.COM. (Refer to the HP OpenVMS System Manager's Manual for more information.) The
LAT characteristics defined in LAT$SYSTARTUP.COM will take effect.
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SHUT
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Specifies that new LAT connections cannot be created on your local
node, but existing connections may continue. The LAT protocol continues
running only until the last active session disconnects, (after which
LTDRIVER will stop). At that time, your node changes to the OFF state.
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Caution
If you stop the LAT software by specifying either the SET
NODE/STATE=OFF or SET NODE/STATE=SHUT command, the LAT print symbiont
(LATSYM) will shut down all print queues that it is processing. The
system will then generate an OPCOM message indicating that the print
queues are stopped. You must manually restart those print queues.
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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=value
Specifies 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:
- When LATCP reaches the maximum unit number, it will continue to
implicitly create LTA devices beginning with the lowest available unit
number.
- You cannot use the System Generation utility (SYSGEN) to set the
maximum unit number for a LAT device.
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:
- List them separated by commas.
- Specify a range.
The available options are as follows:
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ENABLE=
group-code[,...]
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Gives your node access to the listed user groups.
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DISABLE=
group-code[,...]
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Prevents your node from accessing the listed groups. The listed groups
were enabled previously.
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ENABLE=
group-code[,...],
DISABLE=group-code[,...]
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This option lets you enable certain groups and disable other groups in
one command line: gives your node access to the groups listed with the
ENABLE option and prevents your node from accessing the groups listed
with the DISABLE option. Enclose both ENABLE and DISABLE in
parentheses; for example, /GROUP=(ENABLE=(10,12),
DISABLE=(1-30)).
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Description
The SET NODE command, which is typically executed in the site-specific
LAT configuration command procedure, LAT$SYSTARTUP.COM, allows you to
specify such characteristics as:
- Node name
- Node identification
- Service and user groups
- Timing of service announcements
- The maximum number of LAT sessions allowed simultaneously on the
node
- The maximum number of outgoing sessions and incoming interactive
sessions
Because LATCP commands change characteristics dynamically (that is, the
commands take effect immediately), you can use the SET NODE command any
time the LAT port driver is active. These changes remain in effect
until the LAT port driver stops. To make sure the changes take effect
when you start the LAT port driver again, edit LAT$SYSTARTUP.COM to
include these changes. Start the LAT port driver by invoking
LAT$SYSTARTUP.COM.
The HP OpenVMS System Manager's Manual contains additional information about the LAT network
in general and service nodes in particular.
Note
The SET NODE command must be executed first (after LTDRIVER is loaded
and the LATACP is started) to ensure that other management commands
execute properly thereafter.
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Examples
| #1 |
LATCP> SET NODE DUKE /IDENT="NODE DUKE, SALES VMSCLUSTER"
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This command specifies node name DUKE for your local node. The
identification string "NODE DUKE, SALES VMSCLUSTER" is multicast from
node DUKE.
| #2 |
LATCP> SET NODE /MULTICAST_TIMER=50 /GROUPS=(ENABLE=(1-3,8,11),DISABLE=5)
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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.
| #3 |
LATCP> SET NODE /CONNECTIONS=BOTH /USER_GROUPS=(ENABLE=(24,121-127),DISABLE=0)
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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.
| #4 |
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)
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This command sets many characteristics at once for node DUKE.
SET PORT
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.
Format
SET PORT port-name
Parameter
port-name
Specifies the name of the port. A port name must be in the form
LTAn:, where n is a unique number from 1 to 9999.
Note
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.
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Qualifiers
/APPLICATION
Specifies 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 HP 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.
/DEDICATED
Specifies that a logical port on your local node is dedicated to an
application service. The /DEDICATED qualifier requires the /SERVICE
qualifier.
To set up an application service for a logical port on a LAT service
node:
- 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.
/LIMITED
Specifies 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).
/LOG
/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-name
Specifies 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-password
Specifies the password required to access a remote service that is
logically associated with the specified application port.
/PORT=remote-port-name
Specifies 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.
/QUEUED
/NOQUEUED
Specifies 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-name
Specifies 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.
Description
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.
Examples
See the examples for the SHOW PORT command for displays that reflect
the changes made by the following SET PORT command examples.
| #1 |
LATCP> SET PORT LTA22: /APPLICATION /NODE=TS33EW /PORT=LN02
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