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The Digital Equipment Corporation (Digital) Local Area Transport (LAT) protocol is the one used most often to connect to Digital hosts. LAT is a Digital-proprietary protocol. Cisco provides LAT technology licensed from Digital. This chapter describes the commands used to configure the LAT transmission protocol on the protocol translators. For configuration information and examples, refer to the chapter "Configuring LAT" earlier in this publication.
To define restrictions on incoming and outgoing connections, use the access-class line configuration command. To remove the access-list number, use the no form of the command.
access-class access-list-number {in | out}| access-list-number | Specifies an integer between 1 and 199 that defines the access list. |
| in | Controls which nodes can make LAT connections into the server. |
| out | Defines the access checks made on outgoing connections. (A user who types a node name at the system prompt to initiate a LAT connection is making an outgoing connection.) |
Disabled
Line configuration
This command defines access-list numbers that will then be used with the lat access-list command to specify the access conditions.
The value supplied for the number argument in both variations of the access-class command is used for all protocols supported by the protocol translator. If you are already using an IP access list, you must define LAT (and possibly X.25) access lists permitting connections to everything, to emulate the behavior of previous software versions.
When both IP and LAT connections are allowed from a terminal line and an IP access list is applied to that line with the access-class command, you must also create a LAT access list with the same number if you want to allow any LAT connections from that terminal. You can specify only one incoming and one outgoing access list number for each terminal line. When checking LAT access lists, if the specified list does not exist, the system denies all LAT connections.
The following example configures an incoming access class on virtual terminal line 4:
line vty 4
access-class 4 in
lat access-list
To delete an entry from the list of queued host-initiated connections, enter the clear entry EXEC command at the system prompt.
clear entry number| number | An entry number obtained from the show entry EXEC command |
EXEC
The following example illustrates how to delete pending entry number 3 from the queue:
pt# clear entry 3
show entry
To specify access conditions to nodes on the LAT network, use the lat access-list global configuration command. To remove a specified access list number, use the no form of the command.
lat access-list number {permit | deny} nodename| number | Specifies a number between 1 and 199 assigned to the line using the access-class line configuration command. |
| permit | Allows any matching node name to access the line. |
| deny | Denies access to any matching node name. |
| nodename | Specifies the name of the LAT node, with or without regular expression pattern matching characters, with which to compare for access. The UNIX-style regular expression characters allow for pattern matching of characters and character strings in the node name. |
No access conditions defined.
Global configuration
Regular expressions are case sensitive. Because LAT node names are always in all capital letters, make sure you use only all capital-letter regular expressions.
Table 6-1 and Table 6-2 summarize pattern and character matching symbols and their use. A more complete description of the pattern matching characters is found in the appendix "Regular Expressions" later in this publication.
| Character | Description |
|---|---|
| \0 | Replaces the entire original address. |
| \1..9 | Replaces the strings that match the first through ninth parenthesized part of X.121 address. |
| * | Matches 0 or more sequences of the regular expressions. |
| + | Matches 1 or more sequences of the regular expressions. |
| ? | Matches the regular expression of the null string. |
| Character | Description |
|---|---|
| ^ | Matches the null string at the beginning of the input string. |
| $ | Matches the null string at the end of the input string. |
| \char | Matches char. |
| . | Matches any single character. |
The following example illustrates how to enter a request to permit all packets destined for any LAT node named WHEEL:
lat access-list 1 permit WHEEL
The following example illustrates how to enter a request to deny all packets destined for any LAT node name beginning with the BLDG1- prefix:
lat access-list 2 deny ^BLDG1-
access-class
To enable LAT, use the lat enabled interface configuration command. To disable LAT, use the no form of the command.
lat enabledThis command has no arguments or keywords.
Enabled
Interface configuration
The following example enables LAT on interface Ethernet 0:
interface ethernet 0
lat enabled
The following example disables LAT on the same Ethernet interface:
interface ethernet 0
no lat enabled
Use the lat group-list global configuration command to allow a name to be assigned to the group list. A group list is any combination of group names, numbers, or ranges. To remove the specified group list, use the no form of the command.
lat group-list groupname {number | range | all} [enabled | disabled]| groupname | Specifies a group code name. |
| number | Specifies a group code number.You can also enter both a group code name and group code numbers. |
| range | Specifies a hyphenated range of numbers. |
| all | Specifies the range from 0 to 255. |
| enabled | (Optional) Allows incremental changes to the list; that is, you can add a group code without retyping the entire command. |
| disabled | (Optional) Allows selective removal of a group code from the list. |
No group names are assigned to the list.
Global configuration
Specifying a name for a group list simplifies the task of entering individual group codes. In other words, a name makes it easier to refer to a long list of group code numbers. The group list must already exist. Use the EXEC command show lat groups to see a list of existing groups.
The following example creates the new group named stockroom and defines it to include the group numbers 71 and 99:
lat group-list stockroom 71 99
The following example adds group code 101 to the group named stockroom:
lat group-list stockroom 101 enabled
The following example deletes the group named Bldg-2:
no lat group-list Bldg-2
lat out-group
lat service-group
To set the number of receive buffers that will be negotiated when the protocol translator is acting as a LAT host, use the lat host-buffers global configuration command. To return to the default of one receive buffer, use the no form of the command.
lat host-buffers receive-buffers| receive-buffers | An integer that specifies the number of receive buffers that will be negotiated. The argument can be any number between 1 and 128. |
1 receive buffer
Global configuration
Before LAT Version 5.2, LAT allowed only one outstanding message at a time on a virtual circuit. This could limit the performance of large protocol translators. For example, only one Ethernet packet of data could be in transit at a time. With LAT Version 5.2, nodes can indicate that they are willing to receive more than one message at a time. During virtual circuit startup, each side communicates to the other how many outstanding messages it is willing to accept.
The following example enables LAT and configures the LAT host to negotiate 100 receive buffers:
lat enabled
lat host-buffers 100
lat server-buffers
To set the rate of the keepalive timer, use the lat ka-timer global configuration command. To restore the default, use the no form of the command.
lat ka-timer seconds| seconds | Timer rate in seconds |
20 seconds
Global configuration
The keepalive timer sets the rate that messages are sent in the absence of actual traffic between the protocol translator and the remote node. The server uses keepalive messages to detect when communication with a remote node is disrupted or when the remote node has crashed.
The following example sets the keepalive timer to rate of five seconds:
lat ka-timer 5
To change the LAT node name without changing the system host name, use the lat node global configuration command.
lat node node-name| node-name | Name of the LAT node |
No default LAT node name
Global configuration
This command allows you to give the server a node name that is different than the host name. Use the EXEC command show entry to determine which LAT hosts have queue entries for printers on the servers. Use the EXEC command clear entry to delete entries from the queue.
The following example specifies the LAT node name as DEC2:
lat node DEC2
clear entry
show entry
To define a group list for a line's outgoing user-initiated connections, use the lat out-group line configuration command.
lat out-group {groupname | number | range | all}| groupname | Specifies a group code name. |
| number | Specifies a group code number.You can also enter both a group code name and group code numbers. |
| range | Specifies a hyphenated range of numbers. |
| all | Specifies the range from 0 to 255. |
The default group code number is 0.
Line configuration
Use the EXEC command show lat to display group numbers. If the host node and protocol translator do not share a common group number, the host's services will not be displayed.
Use the command lat out-group 0 to return to the default value.
The following example defines the services for lines 1 through 7, 10 through 17, and 20 through 24. Access to systems on the first set of lines is limited to groups 12 and 18 through 23; the second set is limited to group 12; the third set is limited to group codes 12, 18 through 23, and 44. All other lines use the default of group zero.
line 1 7
lat out-group 12 18-23
line 10 17
lat out-group 12
line 20 24
lat out-group 12 18-23 44
A dagger (+) indicates that the command is documented in the Remote Access Server Connection Guide.
terminal lat out-group+
lat group-list
To set the number of times that LAT retransmits a message before declaring the remote system unreachable, use the lat retransmit-limit global configuration command. To restore the default retry value, use the no form of the command.
lat retransmit-limit number| number | Number of retries--any number between 4 and 255 |
8 retries
Global configuration
Assigning larger values to the number of tries increases the robustness of the LAT service at the cost of longer delays when communications are disrupted. Because LAT generally retransmits messages once a second, the value is approximately the number of seconds that LAT connections will survive connection disruption.
If you bridge LAT, the retransmission limit should be set to at least 20 tries for LAT sessions to survive a worst-case spanning-tree reconfiguration, because bridging spanning-tree reconfiguration can take up to 15 seconds.
The following example sets the retransmission limit to 30 tries, enough time to sustain the down time incurred when the system must reconfigure a spanning-tree topology:
lat retransmit-limit 30
To set the number of receive buffers that will be negotiated when the protocol translator is acting as a LAT server, use the lat server-buffers global configuration command. To return to the default of one receive buffer, use the no form of the command.
lat server-buffers receive-buffers| receive-buffers
| Integer that specifies the number of receive buffers that will be negotiated. The argument can be any number between 1 and 128. |
1 receive buffer
Global configuration
Before LAT Version 5.2, LAT allowed only one outstanding message on a virtual circuit at a time. This could limit the performance of large protocol translators because only one Ethernet packet of data could be in transit at a time. With LAT Version 5.2, nodes can indicate that they are willing to receive more than one message at a time. During virtual circuit startup, each side communicates to the other how many outstanding messages it is willing to accept.
The following example enables LAT and configures the server to negotiate 25 receive buffers:
lat enabled
lat server-buffers 25
lat host-buffers
To associate a command with a service, use the lat service autocommand global configuration command. To remove the specified autocommand, use the no form of this command.
lat service service-name autocommand command| service-name | Name of the service |
| command | Command to be associated with the service |
No commands automatically associated with a service.
When an inbound connection is received for the specified service, the command associated with the service is automatically executed instead of the user receiving a virtual terminal session.
TACACS or port passwords are bypassed for these services; only the LAT password is checked.
The following example associates the command telnet china-cat to the service CHINA-CAT:
lat service CHINA-CAT autocommand telnet china-cat
To enable inbound connections to the specified service and enable the advertisement of this service to protocol translators on the network, use the lat service enabled global configuration command. To delete the named service, use the no form of the command. Deleting a service does not disconnect existing connections.
lat service service-name enabled| service-name | Name of the service |
No services enabled
Global configuration
In the simplest form, this command creates a service that gives connecting users access to a VTY port on the server.
Use the enabled keyword after commands that define a service so that users do not connect to a service before all the parameters are set.
The following example illustrates how to enable inbound connections to the service WHEEL:
lat service WHEEL enabled
To set the LAT service identification for a specified service, use the lat service ident global configuration command. To remove the identification, use the no form of this command.
lat service service-name ident identification| service-name | Name of the service |
| identification | Descriptive name (text only) that identifies the service |
No LAT service identification set for specific services.
Global configuration
The identification is advertised to other servers on the network and is displayed along with the list of name services on the LAN.
The following example specifies the identification "Welcome to Gateway-A" on service STELLA:
lat service STELLA ident Welcome to Gateway-A
To set up a LAT password for a service, use the lat service password global configuration command. To remove the password, use the no form of this command.
lat service service-name password password| service-name | Name of the service |
| password | Password |
No default LAT service passwords
Global configuration
The connecting user will be required to enter the password to complete the connection.
The password is obtained through the LAT password mechanism; protocol translators running Software Release 8.1 or earlier do not support this capability. Any services protected in this manner cannot be connected by a device running 8.1 or earlier software.
The following example specifies a service named BLUE and the password secret:
lat service BLUE password secret
To set a static service rating for the specified service, use the lat service rating global configuration command. To remove the service rating, use the no form of this command.
lat service service-name rating static-rating| service-name | Name of the service. |
| static-rating | Static service rating. The rating must be in the range of 1 to 255. |
Dynamic rating
Global configuration
If this command is not entered, the protocol translator calculates a dynamic rating based on the number of free ports that can handle connections to the service. Setting a static rating overrides this calculation and causes the specified value to be used.
The following example specifies a service rating of 84 on the service WHEEL:
lat service WHEEL rating 84
To associate a rotary group with a service, use the lat service rotary global configuration command. To remove the association, use the no form of this command.
lat service service-name rotary group| service-name | Name of the service |
| group | Rotary group number |
Disabled
Global configuration
Establish rotary groups using line configuration commands and the rotary line subcommand.
When an inbound connection is received for this service, the protocol translator establishes a reverse-LAT connection to a terminal in that rotary group.
If the rotary option is not set, the connection will be to a virtual terminal session on the protocol translator.
The following example creates a service called MODEM to establish a rotary group:
lat services MODEM rotary 1
A dagger (+) indicates that the command is documented the Router Products Command Reference publication.
rotary+
To specify a group code mask to use when advertising all services for this node and to control incoming services, use the lat service-group global configuration command. To remove the group code mask specified, use the no form of the command.
lat service-group {groupname | number | range | all} [enabled | disabled]| groupname | Specifies a group code name. |
| number | Specifies a group code number. |
| range | Specifies a hyphenated range of numbers between 0 and 255. |
| all | Specifies the range from 0 to 255. |
| enabled | (Optional) Allows incremental changes to the list; that is, you can add a group code without retyping the entire command. |
| disabled | (Optional) Allows selective removal of a group code from the list. |
If no service group is specified, the protocol translator defaults to advertising to group 0.
Global configuration
When this command is written to nonvolatile memory (using the EXEC write memory command), the system looks for an exact match on a group code name. If it finds one, it uses that name in the command. Otherwise, it writes out a list of numbers, using the range syntax whenever possible.
The following example specifies groups 100 through 103, then defines engineering as the group code list to advertise:
lat group-list engineering 100-103
lat service-group engineering enabled
The following example specifies the groups 1, 5, 20 through 36, and 52:
lat service-group 1 5 20-36 52
You can then enter the following command to add group 99:
lat service-group 99 enabled
lat group-list
To set the maximum number of sessions to be multiplexed onto a single LAT virtual circuit, use the lat vc-sessions global configuration command. To remove a prior sessions definition set using the lat vc-sessions command, use the no form of the command.
lat vc-sessions number
| number | Specifies the number of sessions that will be multiplexed onto a single LAT virtual circuit. This number cannot be greater than 255. |
255 sessions per virtual circuit
Global configuration
Setting the number of sessions to a smaller number can increase throughput if there are a large number of sessions to one host, especially with terminal servers with many physical ports. It can also increase overhead if there is little traffic but a large number of sessions to the same host
The following example sets the maximum number of sessions to be multiplexed onto a single LAT virtual circuit at 100:
lat vc-sessions 100
To set the interval of time LAT waits before sending traffic, use the lat vc-timer global configuration command. To remove a timer definition, use the no form of the command.
lat vc-timer milliseconds
| milliseconds | Timer value. Specifies the amount of time LAT will wait before sending traffic. Acceptable values are between 10 and 1000 milliseconds. |
80 milliseconds
Global configuration
Smaller timer values increase the overhead on both the protocol translator and the host. However, you can use smaller values to correct buffer overflows, which happen when the protocol translator receives more data than it can buffer during a virtual circuit timer interval.
Larger values increase the need for protocol translator buffering and can cause noticeable echoing delay. However, increased values can reduce traffic. In environments with slow bridging, retransmissions can be reduced if you increase the value to at least three times the worst-case, round-trip interval.
The following example sets the time between transmitting messages to 500 milliseconds:
lat vc-timer 500
Use the show entry EXEC command to display the list of queued host-initiated connections to a protocol translator. You can use this command to determine which LAT hosts have queue entries for printers on protocol translators.
show entryThis command has no arguments or keywords.
EXEC
The following is sample output from the show entry command. The display shows that two LAT connections are waiting for access to port 5. The list is ordered so that the lower numbered entry has been waiting longer, and will get to use the line next.
sloth# show entry
1 waiting 0:02:22 for port 5 from LAT node BLUE
2 waiting 0:00:32 for port 5 from LAT node STELLA
Table 6-3 describes the fields in the first line of output shown in the display.
| Field | Description |
|---|---|
| 1 | Number assigned to the queued connection attempt |
| waiting 0:02:22 | Interval (hours:minutes:seconds) during which the connection attempt has been waiting |
| for port 5 | Port for which the connection attempt is waiting |
| from LAT node BLUE | Name of the user (BLUE) attempting to make the connection |
Use the show lat advertised EXEC command to display the LAT services a protocol translator offers to other systems running LAT on the network.
show lat advertisedThis command has no arguments or keywords.
EXEC
Advertised services are created with the lat service configuration commands. The display includes the service rating, rotary group, if present, and whether or not the service is enabled for incoming connections.
The following is sample output from the show lat advertised command:
sloth# show lat advertised
Service Name Rating Rotary Flags
CHINA-CAT 4(Dynamic) None Enabled
Autocommand: telnet china-cat
MODEMS 0(Dynamic) 12 Enabled
Ident: SpaceBlazer modem services
RECLUSE 4(Dynamic) None Enabled
Ident: white recluse...
The display shows output from a protocol translator, RECLUSE, which has three services defined: CHINA-CAT, MODEMS, and RECLUSE.
Table 6-4 describes significant fields shown in the display.
| Field | Description |
|---|---|
| Service Name | Lists the LAT service name. |
| Rating | Lists the static service rating set, if any. |
| Rotary | Lists the associated rotary service. |
| Flags | Lists whether or not a service is enabled. |
| Autocommand | Defines the autocommand associated with the service. |
| Ident | Lists the advertised identification for the service. |
Use the show lat groups EXEC command to display the groups that were defined for a protocol translator using the lat group-list global configuration command.
show lat groupsThis command has no arguments or keywords.
EXEC
The following is sample output from the show lat groups command:
sloth# show lat groups
Group Name Len Groups
cafeteria 3 13 15 23
engineering 7 55
manufacturing 10 70 71 72
Table 6-5 describes significant fields shown in the display.
| Field | Description |
|---|---|
| Group Name | Assigned group name |
| Len | Size of internal data structure used to contain the group code map |
| Groups | Group codes associated with the learned group |
lat group-list
Use the show lat nodes EXEC command on a protocol translator to display information about all known LAT nodes.
show lat nodesThis command has no arguments or keywords.
EXEC
The following is sample output from the show lat nodes command:
pt# show lat nodes
Node "CHAOS", usage -1, Interface Ethernet0, Address 0000.0c01.0509
Timer 89, sequence 188, changes 131, flags 0x0, protocol 5.1
Facility 0, Product code 0, Product version 0
Recv 0/0/0, Xmit 0/0/0, 0 Dups, 0 ReXmit
Bad messages: 0, Bad slots: 0, Solicits accepted: 0
Solicits rejected: 0, Multiple nodes: 0
Groups: 0
Service classes: 1
Node "CONFUSED", usage -1, Local
Timer 99, sequence 4, changes 151, flags 0x0, protocol 5.2
Facility 0, Product code 0, Product version 0
Recv 0/0/0, Xmit 0/0/0, 0 Dups, 0 ReXmit
Bad messages: 0, Bad slots: 0, Solicits accepted: 0
Solicits rejected: 0, Multiple nodes: 0
Groups: 0
Service classes: 1
Node "WOMBAT", usage -1, Interface Ethernet0, Address 0000.0cff.c9ed
Timer 99, sequence 9, changes 159, flags 0x0, protocol 5.1
Facility 0, Product code 0, Product version 0
Recv 0/0/0, Xmit 0/0/0, 0 Dups, 0 ReXmit
Bad messages: 0, Bad slots: 0, Solicits accepted: 0
Solicits rejected: 0, Multiple nodes: 0
Groups: 0
Service classes: 1
Node "TARMAC", usage -1, Interface Ethernet0, Address 0000.0c02.c7c1
Timer -10351, sequence 1, changes 131, flags 0x40, protocol 5.2
Facility 0, Product code 0, Product version 0
Recv 0/0/0, Xmit 0/0/0, 0 Dups, 0 ReXmit
Bad messages: 0, Bad slots: 0, Solicits accepted: 0
Solicits rejected: 0, Multiple nodes: 0
Groups: 0
Service classes: 1
Table 6-6 describes significant fields shown in the display.
| Field | Description |
|---|---|
| Node | The node name as reported by the host computer. |
| usage | The number of virtual circuits currently active to this node. |
| Interface | Node interface type and number. |
| Address | The MAC address of the node's Ethernet interface. |
| Timer | The number of seconds remaining until this node's service advertisement message will time out; this value is set to three times the nodes multicast timer value whenever a new service advertisement message is received. |
| sequence | The sequence number received in the last service advertisement message received. Nodes increment their sequence number when the contents of the service advertisement change. |
| changes | The internal representation of what changed in the multicast message the last time the sequence number changed. |
| flags | The internal representation of various state information about the node. |
| protocol | The LAT protocol version used by the node. |
| Facility | The remote facility number. |
| Product code | The remote product code. |
| Product version | The remote product version. |
| Recv and Xmit | The number of messages, slots, and bytes received or transmitted to the node. The number of messages is the number of LAT virtual circuit messages. Each virtual circuit message contains some number of slots, which contain actual terminal data or control information. Bytes is the number of data bytes (input or output characters) exchanged. |
| Dups | The number of duplicate virtual circuit messages received. |
| ReXmit | The number of virtual circuit messages retransmitted. |
| Bad messages | The number of bad messages received. |
| Bad slots | The number of bad slots received. |
| Solicits accepted | The number of solicit-information requests accepted. |
| Solicits rejected | The number of solicit-information requests rejected. |
| Multiple nodes | The total of multiple nodes seen. |
| Groups | The list of group codes advertised by the node's service advertisement message. |
| Service classes | The number of service classes. |
Use the show lat sessions EXEC command on a protocol translator to display information on active LAT sessions.
show lat sessions [line-number]| line-number | (Optional) Use to display information about a single line. |
EXEC
The following is sample output from the show lat sessions command:
orange# show lat sessions
tty0, connection 1 to service TERM1
TTY data:
Name "0", Local usage 1/0, Remote usage disabled
Flags: Local Connects, Enabled
Command Mode flags: none
Config flags: -FlowOut, -FlowIn, Parameter Info
Flow control ^S/^Q in ^S/^Q out, Mode Normal, Parity None, databits 8
Groups: 0
Session data:
Name TERM1, Remote Id 1, Local Id 1
Remote credits 2, Local credits 0, Advertised Credits 2
Flags: none
Max Data Slot 255, Max Attn Slot 255, Stop Reason 0
Remote Node data:
Node "TERM1", Address 0000.0C00.291F, usage 1
Timer 59, sequence 5, changes 159, flags 0x0, protocol 5.1
Recv 56/22/83, Xmit 41/23/14, 0 Dups, 0 ReXmit
Groups: 0
tty10, connection 1 to service ENG2
TTY data:
Name "10", Local usage 1/0, Remote usage disabled
Flags: Local Connects, Enabled
Command Mode flags: none
Config flags: -FlowOut, +FlowIn, Set Parameters, 0x40000000
Flow control ^S/^Q in ^S/^Q out, Mode Normal, Parity None, databits 8
Groups: 0
Session data:
Name ENG2, Remote Id 1, Local Id 1
Remote credits 1, Local credits 0, Advertised Credits 2
Flags: none
Max Data Slot 255, Max Attn Slot 255, Stop Reason 0
Remote Node data:
Node "ENG2", Address AA00.0400.34DC, usage 1
Timer 179, sequence 60, changes 255, flags 0x0, protocol 5.1
Recv 58/29/186, Xmit 50/36/21, 0 Dups, 0 ReXmit
Groups: 0
The following display shows information about active LAT sessions on one line, line 10:
pt# show lat sessions 10
tty10, connection 1 to service ENG2
TTY data:
Name "10", Local usage 1/0, Remote usage disabled
Flags: Local Connects, Enabled
Command Mode flags: none
Config flags: -FlowOut, +FlowIn, Set Parameters, 0x40000000
Flow control ^S/^Q in ^S/^Q out, Mode Normal, Parity None, databits 8
Groups: 0
Session data:
Name ENG2, Remote Id 1, Local Id 1
Remote credits 1, Local credits 0, Advertised Credits 2
Flags: none
Max Data Slot 255, Max Attn Slot 255, Stop Reason 0
Remote Node data:
Node "ENG2", Address AA00.0400.34DC, usage 1
Timer 189, sequence 61, changes 247, flags 0x0, protocol 5.1
Recv 60/29/186, Xmit 52/36/21, 0 Dups, 0 ReXmit
Groups: 0
Table 6-7 describes the screen output for the preceding two examples. The output is divided into three sections: TTY data, sessions data, and remote node data. Where information on more than one session appears, there is a group of three sections for each session, preceded by a line identifying the session.
| Field | Description |
|---|---|
| TTY data | Reports a summary of the LAT-oriented terminal-line specific data. |
| Name | Identifies the name used for a port as a port-identification string. This is reported to remote systems, which might display it in some operating-system dependent manner. This is also the value used for targets of host-initiated connections. Currently, this value is hard-wired to be the line number of the associated terminal line. |
| Local usage Remote usage | Indicate the current status of the terminal. The number is reported as current/maximum, where current is the current number of sessions of a given type, and maximum is the maximum number of sessions allowed, or zero if there is no maximum. If a terminal is being used for outgoing sessions, the local usage will be equal to the number of current LAT sessions. If the terminal is being used for incoming sessions, local usage will be disabled and the remote count and maximum will be one. |
| Flags | Indicate the current state of the line, and whether there are currently any queued host-initiated connections. |
| Command Mode flags | Report flags that are not currently used in this software release. |
| Config flags | Indicate the current port state as reflected by the most recent configuration message exchange. |
| Flow control | Lists set flow control characters. |
| Groups | Report the group code list currently in use for the line. |
| Session data | Reports various parameters about the connection. |
| Name | For outbound connections, indicates the name of the remote service to which the protocol translator is connected. For inbound connections, this field is currently unused. |
| Remote/Local Id | Report the slot IDs being used to uniquely identify the session multiplexed over the underlying LAT virtual circuit. |
| Remote/Local/advertised credits | List the number of flow control credits that the protocol translator will be sending to the host as soon as possible. The advertised credits are the number of credits that have already been extended. |
| Flags | Indicate transient conditions in the LAT state machine dealing with the current connection status. |
| Max Data Slot | Lists the maximum number of characters that can be sent in a single data slot. |
| Max Attn Slot | Lists the maximum amount of data that can be sent in an attention message. Because current LAT implementations only send one-byte attention messages (attention messages are used to flush buffered output), a nonzero value means that remote data flushing can be used, a zero means that it cannot. |
| Stop Reason | Identifies the reason that the session was stopped, if it has been stopped but not deleted. This value is usually zero, indicating that the session has not been stopped yet. If a session persists for a long period of time with a nonzero stop reason, this generally indicates a problem in the local LAT software. |
| Remote Node data | Reports information about the remote node. The data includes the same fields as those from the show lat nodes output. |
Use the show lat traffic EXEC command to display information on traffic and resource utilization statistics on all active lines of a protocol translator.
show lat trafficThis command has no arguments or keywords.
EXEC
The following is sample output from the show lat traffic command:
sloth# show lat traffic
Local host statistics:
0/100 circuits, 0/500 sessions, 1/500 services
100 sessions/circuit, circuit timer 80, keep-alive timer 5
Recv: 335535 messages (2478 duplicates), 161722 slots, 1950146 bytes
0 bad circuit messages, 3458 service messages (52 used)
Xmit: 182376 messages (2761 retransmit), 146490 slots, 36085 bytes
1 circuit timeouts
Total: 23 circuits created, 38 sessions
Table 6-8 describes significant fields shown in the display.
| Field | Description |
|---|---|
| Local host statistics | Information about the protocol translator. |
| circuits | The current number and maximum support number of virtual circuits. |
| sessions | The current and maximum number of sessions. |
| services | The current number of known remote services, and the maximum supported. |
| sessions/circuit | The number of sessions per virtual circuit supported by the software. |
| circuit timer | The value of the virtual-circuit timer parameter defined by the lat vc-timer global configuration command. |
| keep-alive timer | The value defined by the lat ka-timer global configuration command. |
| Recv | Statistics about local node receive totals. |
| messages | The total count of virtual circuit messages received. |
| duplicates | The number of duplicate virtual circuit messages received. |
| slots | The number of slots received. |
| bytes | The actual number of data bytes received. |
| bad circuit messages | The count of invalid messages received. |
| service messages | The number of service advertisement multicast messages received. |
| used | The number of multicast messages that caused the local node information to be updated. |
| Xmit | Various transmission totals. |
| messages | The total number of virtual circuit messages transmitted. |
| retransmit | The number of virtual circuit messages retransmitted due to the lack of an acknowledgment. |
| slots | The number of data and control slots transmitted. |
| bytes | The actual count of user data bytes transmitted. |
| circuit timeouts | The count of times that a virtual circuit timed-out because the remote node stopped responding (due to a node failure or communications failure). |
| Total: | The count of virtual circuits and sessions that have existed since the protocol translator booted or rebooted. |
Use the show node EXEC command to display to display information about LAT nodes. The show node command with no further parameters shows a one-line summary of all known nodes. The show node command displays three different sets of information about a node: the node counters, the node status, or a one-line summary of the node status.
show node [all | node-name] [counters | status | summary]| all | (Optional) Specifies all nodes. |
| node-name | (Optional) Identifies the name of the node for which status is required. |
| counters | (Optional) Specifies the various node counters. |
| status | (Optional) Specifies detailed node status. This is the default if a node name is specified. |
| summary | (Optional) Specifies a status summary for the node. This is the default if no node name is specified. |
EXEC
The show node command with no arguments is the same as entering show node all summary.
The show node command can be entered with either a specific node name or the keyword all, but not both.
The show node command can be entered with only one of the keywords counters, status, or summary. If you enter show node and two of these keywords without specifying a node name, the first keyword is treated as a node name, causing an error. If you enter show node node-name and two of these keywords, the second keyword will be treated as ambiguous.
The following is sample output from the show node command with no further parameters (the same as show node all summary):
pt> show node
Node Name Status Identification
CHAOS Reachable
MUDDY-RIVER Reachable
TARMAC Reachable
WHEEL Reachable Welcome to VAX/VMS V5.4-2
Table 6-9 describes significant fields shown in the display.
| Field | Description |
|---|---|
| Node Name | Lists the names of the nodes. |
| Status | Indicates whether the node is reachable or not. |
| Identification | Lists the identification string for the node. |
The following is sample output from the show node output that defaults to show node chaos status. It results in a display of the detailed status of node chaos.
pt> show node chaos
Node: CHAOS Address: 00-00-0C-01-05-09
LAT Protocol: V5.1 Data Link Frame Size: 1500
Identification:
Node Groups: 0
Service Name Status Rating Identification
CHAOS Available 80
Table 6-10 describes significant fields shown in the display.
| Field | Description |
|---|---|
| Node | Lists the node name as reported by the host computer. |
| Address | Identifies the MAC address of the node's Ethernet interface. |
| LAT protocol | Lists the version of the LAT protocol used by the node. |
| Data Link Frame Size | Lists the size of the largest packet that can be sent to the LAT host. |
| Identification | Lists the identification string for the node. |
| Node Groups | Lists the group code list that is advertised by the remote node it its service advertisement messages.
|
| Service Name | Lists the LAT service name. |
| Status | Indicates whether or not the node is currently available on the network. |
| Rating | Indicates the rating of the service: An integer from 0 to 255, with the highest number being the preferred service. Used for load balancing. |
The following is sample output for the counter information for a specific node.
pt> show node tarmac counters
Node: tarmac
Seconds Since Zeroed: 100 Multiple Node Addresses: 0
Messages Received: 0 Duplicates Received: 0
Messages Transmitted: 0 Messages Re-transmitted: 0
Slots Received: 0 Illegal Messages Received: 0
Slots Transmitted: 0 Illegal Slots Received: 0
Bytes Received: 0 Solicitations Accepted: 0
Bytes Transmitted: 0 Solicitations Rejected: 0
In the following example, the keyword word status is treated as the node name:
pt> show node status counters
Local -710- Node STATUS not known
In the following example, the second keyword counters is treated as ambiguous:
pt> show node lager status counters
Local -702- Keyword "COUNTERS" not known or ambiguous
Use the show service EXEC command on a protocol translator to display specific LAT learned services.
show service [service-name]| service-name | (Optional) The name of a specific LAT service |
EXEC
The show service command without a service name displays a list of known LAT learned services. When entered with the service-name argument, it displays a more detailed status of the named service. If no LAT learned service by the specified name is known, then a lookup is done for an IP host of that name.
The following is sample output from the show service command:
pt> show service
Service Name Status Identification
BLUE Available Welcome to VAX/VMS V5.4
CHAOS Available
MRL12 Available
MUDDY-RIVER Available
STELLA-BLUE Available Welcome to VAX/VMS V5.4
The following display shows sample show service output for a specific service.
pt> show service blue
Service BLUE - Available
Node Name Status Rating Identification
BLUE reachable 84 Welcome to VAX/VMS V5.4
Table 6-11 describes significant fields shown in the two previous displays.
| Field | Description |
|---|---|
| Service | Name of the service. |
| Node Name | Name of the nodes advertising the service. |
| Status | Status of the service: Available or Unknown when command is entered without a service name. Available, Unknown, Initializing, or Unreachable when command is entered with a service name. |
| Rating | Rating of the service: An integer from 0 to 255, with the highest number being the preferred service. Used for load balancing. |
| Identification | Identification string. |
To reenable LAT broadcast service announcements, use the lat service-announcements command. To disable the sending of LAT service announcements, use the no form of the command.
lat service-announcementsThis command has no arguments or keywords.
Enabled
Global configuration
If this command is enabled, the LAT code will periodically broadcast service advertisements. If the command is disabled, the LAT code will not send service announcements, so solicit information messages will have to be used to look up node information.
The following example reenables the sending of broadcast service announcements:
lat service-announcements
lat service-responder
To configure a node to act as proxy for other nodes when a solicit-information multicast message is received, use the lat service-responder global configuration command. To remove any proxy definition set up using the lat service-responder command, use the no form of the command.
lat service-responderThis command has no arguments or keywords.
Disabled
Global configuration
Your protocol translator can be configured to support the service responder feature that is part of the latest LAT Version 5.2 specification.
Specifically, the DECserver90L+, which has less memory than other DECservers, does not maintain a cache of learned services. Instead, the DECserver90L+ solicits information about services as they are needed.
LAT Version 5.2 nodes can respond for themselves but LAT Version 5.1 nodes, for example VMS Version 5.4 or earlier nodes, cannot. Instead, a LAT Version 5.2 node configured as a service responder can respond in proxy for those LAT Version 5.1 nodes.
Your protocol translator can be configured as a LAT service responder. Of course, if all your nodes are LAT Version 5.2 nodes, you do not need to enable the service responder features.
The following example configures a node to act as a proxy for a node when a solicit information multicast message is received. The node configured with this command will respond to solicit messages.
lat service-responder
lat service-announcements
To adjust the time between LAT service advertisements, use the lat service-timer global configuration command.
lat service-timer interval| interval | Number of seconds between service announcements. Note that the granularity offered by this command is ten-second intervals, and the interval value is rounded up. |
20 seconds
Global configuration
This command adjusts the time, in seconds, between LAT service announcements for services offered by the protocol translator. This is useful in large networks with many LAT services and limited bandwidth.
The following example illustrates the rough granularity of the lat service-timer command:
! The time between LAT service advertisements is set to 11. Because the
! granularity is in ten-second intervals, the actual time between advertisement
! is 20 seconds.
lat service-timer 11
! 20 seconds between updates
lat service-timer 19
! 120 seconds between updates
lat service-timer 120
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