The LAPB module implements one of the protocols in the Link layer described
by the Digital Network Architecture.
You must install the product DEC WAN Device Drivers before you can refer
to the LAPB Module entities in an NCL command.
The lapb entity is the top-level entity in the LAPB module hierarchy of
entities. The LAPB module implements the LAPB link-level protocol which is
a variation of the HDLC link-level protocol.
1 – character
VERSION
Default: None Version: Current version number
Version number of the DNA HDLC architecture to which this implementation
conforms. You cannot modify this characteristic.
2 – LINK
A lapb link entity is associated with a port of the supporting Physical
layer, and contains attributes that describe local LAPB operation. The
simple-name refers to the link managed by this command.
2.1 – character
ACKNOWLEDGE TIMER
Default: Supplied by profile Value: 1--60000
Time, in milliseconds, to wait for an acknowledgment before initiating
recovery action. This attribute corresponds to the LAPB parameter T1.
You can modify this characteristic only when the entity is disabled.
HOLDBACK TIMER
Default: Implementation specific Value: 0--60000
Delay, in milliseconds, before an acknowledgment must be sent. This
characteristic corresponds to the LAPB parameter T2. You can modify this
characteristic only when the entity is disabled.
INTERFACE TYPE
Default: DTE Value: DCE or DTE
Address mode for this link.
DCE - Use DCE address mode.
DTE - Use DTE address mode.
You can modify this characteristic only when the entity is disabled.
MAXIMUM DATA SIZE
Default: Supplied by profile Value: 1--65532
Maximum frame size, in octets, of an information field in an I-frame.
PHYSICAL LINE
Default: No default Value: Local-entity-name
Name of the Physical layer and line entity over which the LAPB protocol
is to operate. You must give this characteristic a value before you
enable the link.
POLL TIMER
Default: Implementation specific Value: Supplied by profile
Maximum period in seconds that may elapse without frames being exchanged
on the Data Link. On expiration, an RR(P) is sent to elicit a response
from the other end.
PROFILE
Default: No default Value: String
Name of the X.25 Level 2 Profile that defines subscription details
associated with the PSDN to which this DTE is connected. You cannot
modify this characteristic. This characteristic is set by means of an
argument to the create command.
RECEIVE BUFFERS
Default: Implementation specific Value: 1--128
Specifies the number of receive data buffers.
RETRY MAXIMUM
Default: Supplied by profile Value: 1--255
Maximum number of times that a frame will be retransmitted before
assuming a fatal error, at which point more drastic error recovery
action will be attempted. This characteristic corresponds to the LAPB
parameter N2.
SEQUENCE MODULUS
Default: Supplied by profile Value: 8 or 128
Type of sequence numbering.
8 - Use normal sequence numbering.
128 - Use extended sequence numbering.
WINDOW SIZE
Default: Supplied by profile Value: 1--127
Window size for transmitting and receiving I-frames. This characteristic
corresponds to the LAPB parameter K.
2.2 – counter
BUFFER UNAVAILABLE ERRORS
Number of times that the underlying framing level has indicated system
buffer unavailability to the Data Link layer.
CRC ERRORS RECEIVED
Number of frames received with a bad CRC.
DATA OCTETS RECEIVED
Number of data octets received from the remote station. This value does
not include retransmissions.
DATA OCTETS SENT
Number of data octets sent to the remote station. This value does not
include retransmissions.
DATA PDUS RECEIVED
Number of I-frames received from the remote station. This value does not
include retransmissions.
DATA PDUS SENT
Number of I-frames sent to the remote station. This value does not
include retransmissions.
FRMRS RECEIVED
Number of FRMR frames received.
FRMRS SENT
Number of FRMR frames generated as a result of invalid incoming frames.
POLLS RECEIVED
Number of command frames received with the P-bit set.
REJS RECEIVED
Number of REJ frames received.
REJS SENT
Number of REJ frames transmitted.
RNRS RECEIVED
Number of RNR frames received.
RNRS SENT
Number of RNR frames transmitted.
TIMES ACKNOWLEDGE TIMER EXPIRED
Number of times the local acknowledge timer has expired.
TIMES LINK HALTED
Number of times the link halt event has been generated.
TIMES LINK INITIALIZING
Number of times the link initializing event has been generated.
TIMES LINK INOPERATIVE
Number of times the link inoperative event has been generated.
TIMES LINK MAINTENANCE
Number of times the link maintenance event has been generated.
TIMES LINK RESETTING
Number of times the link reset event has been generated.
TIMES LINK RUNNING
Number of times the link running event has been generated.
TIMES LINK SETUP FAILED
Number of times the link setup failure event has been generated.
TIMES LINK STATE CHANGED
Number of times a link state transition has occurred.
TIMES PDU RECEIVE OVERRUN
Number of times a physical line indicated an overrun condition to the
Data Link layer.
TIMES PDU TRANSMIT FAILED
Number of times an attempt to transmit a frame has failed.
2.3 – status
LINE TYPE
Type of line over which this link operates.
NONSWITCHED - The line is a nonswitched line.
SWITCHED - The line is a switched line.
MAXIMUM PDU SIZE
Maximum frame size, in octets, that this station will receive and
transmit. This value includes the frame header.
PHYSICAL PORT
Name of the Physical layer port with which the link is associated.
PROTOCOL STATE
State of the LAPB protocol with respect to the remote station.
ERROR - The protocol is in a recognized error state.
HALTED - The protocol has halted.
INITIALIZING - The protocol is being initialized.
INOPERATIVE - The protocol cannot be started without connectivity to
the remote station.
MAINTENANCE - The link is in maintenance mode.
RESETTING - The protocol is undergoing a reset operation.
RUNNING - The protocol is running normally.
STATE
Status of the lapb link entity.
OFF - The link is disabled.
ON - The link is enabled.
3 – port
A lapb port entity represents an access point for LAPB module clients to
Data Link layer services. The port-name refers to the port managed by this
command.
3.1 – status
CLIENT NAME
Name of the client with which the port is associated.
LINK
Name of the link with which the port is associated.
STATE
State of the lapb port entity.
OPEN - The port is assigned to a client.
OPEN DISABLED - The port is assigned to a client, but the associated
link is disabled.
TYPE
Type of port.
SEQUENCED - The port is used for sending LAPB data.
UNSEQUENCED - The port is used for sending loopback data. This is only
possible if the maintenance mode characteristic of the
relevant lapb link entity is set to true.