1 – LINK
Changes the characteristics of LAT data links. You must have OPER
privilege to use this command.
Format
SET LINK link-name
1.1 – Parameter
link-name
Specifies the name for a LAT data link. A link name can have up
to 16 ASCII characters. The characters allowed are as follows:
o Alphanumeric characters: A-Z, a-z, 0-9
o A subset of the international character set: ASCII codes 192-
253
o Punctuation characters: dollar sign ($), hyphen (-), period
(.), and underscore (_)
The SHOW LINK command displays the names of the links defined for
a node.
1.2 – Qualifiers
1.2.1 /LOG
/LOG
/NOLOG
Specifies whether LATCP displays a message confirming that the
link's characteristics were modified. If you do not specify the
/LOG or /NOLOG qualifier, the default is that no message will be
displayed.
1.2.2 /STATE
/STATE=option
Specifies availability of the link for use. The two options for
STATE are:
ON Specifies that the link will be available for use with
the LAT protocol running.
OFF Specifies that the link will not be available for use.
If you do not specify the /STATE=option qualifier, the default is
that the link will be available (ON).
1.3 – Example
LATCP> SET LINK NETWORK_A /LOG /STATE=ON
The SET LINK command in this example directs LATCP to start
the controller for link NETWORK_A and then to display a
confirmation message.
2 – NODE
Specifies the LAT characteristics of your local node. You must
have OPER privilege to use this command.
Format
SET NODE [node-name]
2.1 – Parameter
node-name
Specifies a node name for your local node. By default, the node
name is the translation of SYS$NODE. A LAT node name should be
the same as the DECnet node name. If the node is not running
DECnet but will be in the future, VSI recommends that you
define SYS$NODE and use it for both DECnet and LAT node names.
A LAT node name can be from 1 to 16 ASCII characters. The
characters allowed are as follows:
o Alphanumeric characters: A-Z, a-z, 0-9
o A subset of the international character set: ASCII codes 192-
253
o Punctuation characters: dollar sign ($), hyphen (-), period
(.), and underscore (_)
2.2 – Qualifiers
2.2.1 /ANNOUNCEMENTS
/ANNOUNCEMENTS
/NOANNOUNCEMENTS
Allows you to control whether your OpenVMS system multicasts
information to the network.
If you specify /NOANNOUNCEMENTS, LAT service announcements are
disabled on the local node. Remote nodes must rely on the LAT
service responder feature in the LAT protocol V5.2 or higher to
connect to the local node. Therefore, VSI recommends that
you use this qualifier only in a networking environment where
newer model terminal servers and hosts are present (all LAT
hosts, terminal servers, and PCs are running LAT protocol V5.2
or higher).
If you specify /NOANNOUNCEMENTS in an environment where LAT
protocol V5.1 is present, those LAT protocol V5.1 systems (for
example, DECserver 100, 200, and 500 systems) will be unable to
connect to any of the systems that have LAT service announcements
disabled.
2.2.2 /CIRCUIT_TIMER
/CIRCUIT_TIMER[=msecs]
Allows you to control the interval in milliseconds (msecs)
between messages sent from the local node to other service nodes
or terminal servers while connections to those nodes are active.
Use this qualifier only if your node allows outgoing connections
(/CONNECTIONS=OUTGOING_ONLY or /CONNECTIONS=BOTH).
A low value for the interval decreases the response time for the
port but increases the demand on service nodes. Set the circuit
timer in the range of 10 to 1000 msecs.
The default value of 80 msecs gives a generally acceptable
response time while creating a moderately low overhead on the
service nodes. You cannot change this parameter when active or
pending LAT connections exist.
2.2.3 /CONNECTIONS
/CONNECTIONS=option
Allows you to specify the type of connections permissible on the
local node. The four options for CONNECTIONS are:
INCOMING_ Specifies that the local node permit incoming
ONLY connections only.
OUTGOING_ Specifies that the local node permit outgoing
ONLY connections only. Specify this on systems that
can tolerate the overhead associated with outgoing
connections, such as standalone systems.
BOTH Specifies that the local node permit both incoming
and outgoing connections. Specify this on systems
that can tolerate the overhead associated with
outgoing connections, such as standalone systems.
NONE Specifies that the local node disallow both
incoming and outgoing connections.
If you do not specify the /CONNECTIONS=option qualifier, the
default is that the node will permit incoming connections only.
2.2.4 /CPU_RATING
/CPU_RATING=cpu-power
/NOCPU_RATING
The /CPU_RATING qualifier assigns your local node a rating that
represents the power of your node's CPU (central processing unit)
relative to other CPUs in the LAN. The value of cpu-power can
range from 1 (for a CPU with the lowest power) to 100 (for a CPU
with the highest power).
When a terminal server or node requests a connection to a service
that is offered on the local node and one or more other service
nodes, the requesting node selects the service node with the
highest (most favorable) service rating, based on the overall
level of activity of the node that offers the service and
the amount of memory. This selection process is called load
balancing.
You can influence the rating for services on your node by
specifying a value for the /CPU_RATING qualifier. If you specify
a high value for cpu-power, the LAT driver will calculate a
relatively high service rating for services on your node (service
ratings as high as 255 are possible). If you specify a low value,
the LAT driver will calculate relatively low service ratings;
connections will most likely be made to the same service that
is offered on other nodes. In either case, the LAT driver can
calculate a greater range of values for dynamic service ratings
(the entire range from 0 to 255). Consequently, the ratings will
more accurately reflect the availability of the service node.
If you do not specify either the /CPU_RATING=cpu-power or /NOCPU_
RATING qualifier, the default is that no CPU rating will be used
A value of 0 indicates no CPU rating.
2.2.5 /DEVICE_SEED
/DEVICE_SEED[=value]
Sets the default starting number (within a range from 1 through
9999) for the unit numbers that will be assigned to new LTA
devices. Note that when ports are created by assigning a channel
to LTA0: with the $ASSIGN system service, the channel numbers
fall in this same range.
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.
2.2.6 /FORWARD_SESSION_LIMIT
/FORWARD_SESSION_LIMIT[=value]
Controls the number of sessions (a value within a range from 16
through 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.
2.2.7 /GROUPS
/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 manay as 256 groups, numbered 0 through 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:
o Listing them separated by commas
o Specifying a range
The available options are:
ENABLE=group- Gives the listed groups access to your service
code[,...] node.
DISABLE=group- Prevents the listed groups from accessing
code[,...] your service node. The listed groups had been
enabled previously for access to your node.
ENABLE=group- This option lets you enable certain groups
code[,...], and disable other groups in one command line:
DISABLE=group- gives access to the groups listed with the
code[,...] 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)).
2.2.8 /IDENTIFICATION
/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 SHOW NODE command or the
DECserver SHOW NODE command 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$ANNOUNCE longer than that will be
truncated to the first 64 characters). Enclose the string in
quotation marks (" ").
2.2.9 /KEEPALIVE_TIMER
/KEEPALIVE_TIMER[=secs]
Allows you to control the maximum interval between idle run
messages sent by your local node to another service node to which
it has a LAT connection. The interval is in seconds. Your node
sends these messages when no other traffic is being generated
over the virtual circuit. If the service node acknowledges
these messages, your node will continue to monitor the status
of the circuit. If your node does not receive acknowledgment, it
responds as if the circuit is down.
Use this qualifier only if your node allows outgoing connections
(/CONNECTIONS=OUTGOING_ONLY or /CONNECTIONS=BOTH).
The default value is 20. VSI recommends this value for
normal LAN environments. For a heavily loaded LAN, consider
using a higher value. Set the timer in the range of 10 to 255.
For applications that require quick notification and possible
failover of a service node failure, use a lower value. You cannot
change this value if active or pending connections exist.
2.2.10 /LARGE_BUFFER
/LARGE_BUFFER
/NOLARGE_BUFFER
Allows you to control whether the LAT software uses large buffers
while managing communications between OpenVMS systems (the
default).
If you must use the /NOLARGE_BUFFER qualifier (for example, to
limit packet sizes to be no larger than the Ethernet maximum),
VSI recommends that you specify this command after all
logical LAT links have been created and before the LAT node
has been turned on. For example, note following commands in
LAT$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
2.2.11 /LOG
/LOG
/NOLOG
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.
2.2.12 /MULTICAST_TIMER
/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.
2.2.13 /NODE_LIMIT
/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.
2.2.14 /QUEUE_LIMIT
/QUEUE_LIMIT=value
Allows you to set 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.
2.2.15 /RETRANSMIT_LIMIT
/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.
2.2.16 /SERVICE_RESPONDER
/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.)
VSI 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.
2.2.17 /SESSION_LIMIT
/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:
INCOMING=value Sets the session limit for incoming
connections only. The default is no
limit (a value of 0).
OUTGOING=value Sets the session limit for outgoing
connections only. The default is no
limit (a value of 0).
INCOMING=value,OUTGOING=valuSets the limit for both outgoing
and incoming connections. Enclose
both options in parentheses; for
example, /SESSION_LIMIT=(INCOMING=20,
OUTGOING=25).
o A high limit allows users to have more sessions but increases
memory utilization on your local node.
o 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.
2.2.18 /STATE
/STATE=option
Specifies whether LAT connections are allowed. The three options
for STATE are:
ON Starts the LAT port driver (and LAT protocol software)
on your node.
VSI 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:
o 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 $DASSGN
system service or the LATCP DELETE PORT command,
for example). Because every LATCP management port
(LATCP$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.
o The deletion of leftover LTA devices with a reference
count of 0 minimizes the use of nonpaged pool memory.
OFF 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$STARTUP.COM. The LAT characteristics defined in
LAT$SYSTARTUP.COM will take effect.
SHUT 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.
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.
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).
2.2.19 /UNIT_NUMBER_MAXIMUM
/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.
Note the following as well:
o When LATCP reaches the maximum unit number, it will continue
to implicitly create LTA devices beginning with the lowest
available unit number.
o You cannot use the System Generation (SYSGEN) utility to set
the maximum unit number for a LAT device.
The range of maximum unit numbers is 99 through 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.
2.2.20 /USER_GROUPS
/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:
o List them separated by commas
o Specify a range
ENABLE=group- Gives your node access to the listed user
code[,...] groups.
DISABLE=group- Prevents your node from accessing the listed
code[,...] groups. The listed groups were enabled
previously.
ENABLE=group- This option lets you enable certain groups
code[,...], and disable other groups in one command
DISABLE=group- line: gives your node access to the groups
code[,...] 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)).
2.3 – Examples
1.LATCP> SET NODE DUKE /IDENT="NODE DUKE, SALES VMSCLUSTER"
The SET NODE command in this example 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-
_LATCP> /GROUPS=(ENABLE=(1-3,8,11),DISABLE=5)
The SET NODE command in this example 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-
_LATCP> /USER_GROUPS=(ENABLE=(24,121-127),DISABLE=0)
The SET NODE command in this example 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 -
_LATCP> /MULTICAST_TIMER=60 /GROUPS=(DISABLE=0,ENABLE=73-)
_LATCP> /SESSION_LIMIT=(OUTGOING=10,INCOMING=0)
The SET NODE command in this example sets many characteristics
at once for node DUKE.
3 – 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
3.1 – 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 through 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.
3.2 – Qualifiers
3.2.1 /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. See 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.
3.2.2 /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:
1. 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$SYSTARTUP.COM.
2. Associate the dedicated ports with the service by specifying
the SET PORT/DEDICATED/SERVICE command.
3. Start the application program. Within the program, allocate
dedicated ports with the same name as those defined in
LAT$SYSTARTUP.COM.
3.2.3 /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).
3.2.4 /LOG
/LOG
/NOLOG
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.
3.2.5 /NODE
/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.
3.2.6 /PASSWORD
/PASSWORD=remote-password
Specifies the password required to access a remote service that
is logically associated with the specified application port.
3.2.7 /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.
3.2.8 /QUEUED
/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.
3.2.9 /SERVICE
/SERVICE=service-name
Specifies either of the following:
o 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
o 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.
You can also set up the port as a limited port, using the
/LIMITED qualifier.
3.3 – Examples
1.LATCP> SET PORT LTA22: /APPLICATION /NODE=TS33EW /PORT=LN02
The SET PORT command in this example 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.
2.LATCP> SET PORT LTA19: /APP /NODE=TLAT1 /SERVICE=PRINTER /QUEUED
The SET PORT command in this example 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. See the description
of print operations in the OpenVMS System Manager's Manual for
information on setting up print queues.
3.LATCP> SET PORT LTA21: /DEDICATED /SERVICE=GRAPHICS
The SET PORT command in this example 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.
4.LATCP> SET PORT MAIL_PORT /SERVICE=MAIL/NODE=RMNODE
The SET PORT command in this example 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 an OpenVMS DCL ASSIGN or
DEFINE command. On node RMNODE, a port must be dedicated to
the service MAIL by using the SET PORT port-name /DEDICATED
/SERVICE=MAIL command.
5.$ LCP :== $LATCP
$ LCP CREATE SERVICE/LIMITED ONLY_ONE
$ LCP CREATE PORT/LIMITED LTA1234:
$ 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.
4 – SERVICE
Dynamically changes the characteristics of a locally offered
service. You must have OPER privilege to use this command.
Format
SET SERVICE [service-name]
4.1 – Parameter
service-name
Specifies 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.
4.2 – Qualifiers
4.2.1 /APPLICATION
Sets 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.
4.2.2 /CONNECTIONS
/CONNECTIONS
/NOCONNECTIONS
Specifies 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).
4.2.3 /IDENTIFICATION
/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 SHOW NODE command or the
DECserver SHOW NODE command 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 (" ").
4.2.4 /LIMITED
Specifies 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).
4.2.5 /LOG
/LOG
/NOLOG
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.
4.2.6 /QUEUED
/QUEUED
/NOQUEUED
Specifies 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.
4.2.7 /STATIC_RATING
/STATIC_RATING=rating
/NOSTATIC_RATING
Enables 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 as well 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.
4.3 – Examples
1.LATCP> SET SERVICE SALES /IDENT="SALES FORCE TIMESHARING SERVICES"
The SET SERVICE command in this example 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.
2.$ 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.