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 /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.
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.
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.
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.
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.
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)).
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$ANNOUNCE longer than that will be
truncated to the first 64 characters). Enclose the string in
quotation marks (" ").
9 /KEEPALIVE_TIMER
/KEEPALIVE_TIMER[=secs]
Allows you to control the maximum interval between idle run
messages sent by your local node to another service node to which
it has a LAT connection. The interval is in seconds. Your node
sends these messages when no other traffic is being generated
over the virtual circuit. If the service node acknowledges
these messages, your node will continue to monitor the status
of the circuit. If your node does not receive acknowledgment, it
responds as if the circuit is down.
Use this qualifier only if your node allows outgoing connections
(/CONNECTIONS=OUTGOING_ONLY or /CONNECTIONS=BOTH).
The default value is 20. VSI recommends this value for
normal LAN environments. For a heavily loaded LAN, consider
using a higher value. Set the timer in the range of 10 to 255.
For applications that require quick notification and possible
failover of a service node failure, use a lower value. You cannot
change this value if active or pending connections exist.
10 /LARGE_BUFFER
/LARGE_BUFFER
/NOLARGE_BUFFER
Allows you to control whether the LAT software uses large buffers
while managing communications between OpenVMS systems (the
default).
If you must use the /NOLARGE_BUFFER qualifier (for example, to
limit packet sizes to be no larger than the Ethernet maximum),
VSI recommends that you specify this command after all
logical LAT links have been created and before the LAT node
has been turned on. For example, note following commands in
LAT$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
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.
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.
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.
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.
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.
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.
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.
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).
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.
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)).