NS 3000/iX LAP-B Link Statistics

LINKSTATE Parameter Fields

Figure A-1 “LINKSTATE Command for LAP-B Link ” provides an example of the data that is displayed when you issue the LINKCONTROL linkname;STATUS=LINKSTATE command:

Figure A-1 LINKSTATE Command for LAP-B Link

Linkname. The Linkname field specifies the name of the link.

Linktype. This Linktype specifies the type of link, such as LAP-B or IEEE 802.3, that is being monitored.

Linkstate. The Linkstate field specifies the current state of the link. The possible link states are as follows:

In this example, in Figure A-1 “LINKSTATE Command for LAP-B Link ”, the current state of the LAPB link named LAPB20 is CONNECTED LEVEL 2.

The LINKSTATE parameter fields are displayed whenever you enter the LINKCONTROL Status command, regardless of which other parameters are specified.

CONFIGURATION Parameter Fields

The CONFIGURATION parameter for LAP-B links displays the LINKSTATE parameter fields and many additional fields. These additional fields display information that is related to the link configuration and which, except for the Cable Type parameter, are input through the NMMGR configuration program.

Figure A-2 “LAP-B CONFIGURATION Parameter Output” provides an example of the data that is displayed when you issue the LINKCONTROL linkname;STATUS=CONFIGURATION command:

Figure A-2 LAP-B CONFIGURATION Parameter Output

Phone Number. The Phone Number field displays the current automatic dial phone number, as specified in the NMMGR configuration file.

Modulo Count. The Modulo Count field displays the maximum frame sequence number allowable for any frame in the network. This field can be set to a value of 8 or 128, meaning that frames are numbered from either 0 through 7, or 0 through 127.

Cable Type. The Cable Type field displays the cable type that is currently connected to the PSI card. This data is provided by the PSI card and cannot be configured through NMMGR. The possible values for this field are as follows:

Local Mode. The Local Mode field displays the value specified for local mode in the NMMGR link screen. The possible values for this field are as follows:

Buffer Size. The Buffer Size field displays the current buffer size. This value will be equal to the buffer size configured in the NMMGR Link screen plus 4 bytes of overhead that is added by the level 3 protocol.

LAPB Parm K. The LAPB Parm K field displays the configured number of unacknowledged frames that are allowed in the network at any given time. For example, if this value is set to seven (7) for a node, and that node transmits seven (7) packet frames onto the network, it cannot transmit another frame until one or more of the transmitted frames are acknowledged.

Connect Timeout. The Connect Timeout field displays the current logical link level 2 connection timeout. The Connect Timeout parameter sets the amount of time a node will wait for a logical connection to a remote node to be established. If this timer expires, the node aborts the connection attempt. The abort process can take several additional seconds.

LAPB Parm T1. The LAPB Parm T1 field displays the current value of the T1 timer. The T1 timer waits the specified number of hundredths-of-seconds for a particular frame to be acknowledged. A frame that is transmitted, but not acknowledged, before the T1 timer expires, is retransmitted.

Local Timeout. The Local Timeout field displays the value specified for the Local timer. This timer, also called a heartbeat timer, is used to monitor whether the system and/or the PSI card are functioning. The PSI card, and the system, transmit a signal, called a heartbeat signal, to each other on a specified schedule. If, for example, the heartbeat does not arrive at the PSI card from the system (or vice-versa), the card or system waits the number of seconds specified by this field. If no heartbeat arrives before this timer expires, the link is dropped. You can determine whether the PSI card or the system failed by checking to see which device is still active. The default for this field is 60 seconds and it is recommended that you do not change the value of this field. The PSI always waits 20 seconds longer than the system waits before it drops the link.

LAPB Parm N2. The LAPB Parm N2 field displays the maximum number of times a frame is retransmitted after the LAPB Parm T1 expires. The frame is retransmitted at the LAPB Parm T1 interval for the number of times specified in this field. When this count is depleted, the frame is retransmitted at 20 second intervals. If no response is received after these transmissions, the link is brought down.

A node that is configured with the value specified in Figure A-2 “LAP-B CONFIGURATION Parameter Output” will attempt to retransmit an unacknowledged frame a maximum of 20 times at T1 intervals.

Transmission Speed. The Transmission Speed field displays the current transfer rate, or clocking, configured for the node in the NMMGR Link screen. If modems are used, the modems will control the clocking. The PSI card transmits at the clocking setting of the modem and ignores the value configured in this field.

STATISTICS Parameter Fields

The STATISTICS parameter for LAP-B links displays many fields in addition to the LINKSTATE parameter fields. The CONFIGURATION parameter fields are not displayed with this parameter. Figure A-3 “LAP-B STATISTICS Parameter Output ” is an example of the data that is displayed when you issue the LINKCONTROL linkname;STATUS=STATISTICS command:

Figure A-3 LAP-B STATISTICS Parameter Output

Connect Duration. The Connect Duration field displays the length of time that the current logical (level 2) connection has existed. If there is no active connection, this field displays the length of time that the most recently established connection was in existence. This field is reset with each new connection.

Tracing. The Tracing field specifies whether tracing is currently enabled or disabled.

Data Bytes Sent. The Data Bytes Sent field displays the number of bytes that have been transmitted in the data portion of all data frames.

Data Bytes Received. The Data Bytes Received field displays the number of bytes that have been received in the data portion of all data frames.

Overhead Bytes Sent. The Overhead Bytes Sent field displays the total number of flags, level 2 address and control bytes, and frame check sequence (FCS) bytes transmitted. This value should be equal to six times the total number of frames transmitted.

Overhead Bytes Received. The Overhead Bytes Received field displays the total number of flags, level 2 address and control bytes, and FCS bytes received. This value should be equal to six times the total number of frames transmitted.

Total Frames Sent. The Total Frames Sent field displays the total number of frames transmitted.

Total Frames Received. The Total Frames Received field displays the total number of frames received.

Data Frames Sent. The Data Frames Sent field displays the total number of transmitted data frames.

Data Frames Received. The Data Frames Received field displays the total number of received data frames.

Aborted Frames Sent. The Aborted Frames Sent field displays the number of frames which were aborted before they were received. Normally, this number should be quite low (below 3% of the total number of frames sent). A large number could point to a noisy line or a weak or bad clock signal sent by a modem. If this value becomes larger than 3% of the total number of frames sent, and you feel that network performance is being affected, contact your HP representative.

Aborted Frames Received. The Aborted Frames Received field displays the number of frames which were aborted after they were received. Normally, this number should be quite low (below 3% of the total number of frames received). A large number could point to a noisy line or a weak or bad clock signal sent by a modem. If this value becomes larger than 3% of the total number of frames received, and you feel that network performance is being affected, contact your HP representative.

DSR Losses. The DSR Losses field displays the number of times the PSI detected a temporary loss of the Data Set Ready (DSR) signal on the cable. On most lines, this will remain at a value of zero, although some modems will periodically drop signals for very short intervals.

Oversized Frames Received. The Oversized Frames Received field displays the number of frames received that exceed the maximum configured buffer size as configured in the Link screen of NMMGR. A number other than zero in this field indicates that the remote buffer size configuration is greater than the local buffer size configuration. One or both configurations must be modified so that the two buffer sizes are identical.

CTS Carrier Losses. The CTS Carrier Losses field displays the number of times the PSI detected a temporary loss of the Clear to Send (CTS) signal on the cable. On most lines, this will remain at a value of zero, although some modems will periodically drop signals for very short intervals.

Receive Overruns. The Receive Overruns field displays the number of times that the PSI card had to discard a frame because the PSI card could not process the data as quickly as it arrived. A number in this field that is greater than 3% of the total number of received frames indicates a possible problem with the PSI card. If this number continues to increase, contact your HP representative.

DCD Carrier Losses. The DCD Carrier Losses field displays the number of times the PSI detected a temporary loss of the Data Carrier Detect (DCD) signal on the cable. On most lines, this will remain at a value of zero, although some modems will periodically drop signals for very short intervals.

CRC Errors. The CRC Errors field displays the number of frames that were received with a bad Cyclic Redundancy Check (CRC) checksum. A large number (greater than 1% of the total number of packets) indicates that a problem may exist in the connection between the PSI and the modem, or between the two modems.

Statistics Resets. The Statistics Resets field displays the number of times that the statistics buffer (which contains the values for all of the aforementioned fields) was reset. This value is reset each time the link is restarted.

RESET Parameter Fields

The RESET parameter for LAP-B links resets all of the accumulated statistics for the links. This command also displays all of the LINKSTATE, CONFIGURATION, and STATISTICS parameter fields. Refer to the STATISTICS parameter for a description of the displayed fields.

ALL Parameter Fields

The ALL parameter for LAP-B links displays all of the LINKSTATE, CONFIGURATION, and STATISTICS parameter fields. Figure A-4 “LAP-B ALL Parameter Output” is an example of the ALL parameter output:

Figure A-4 LAP-B ALL Parameter Output