LINKCONTROL


LINKCONTROL

     Prints link status information, or activates or deactivates
link level tracing on the specified data communications
line. Node Manager (NM) capability is required.

In addition to the normal help text you will find a extended
discussion of the complete output.

SYNTAX


LINKCONTROL [LINKNAME=] { @ }
{linkname }

[{;STATUS=} {A[LL]} ]
[{ } {L[INK[STATE]]} ]
[ {C[ONF[IGURATION]]} ]
[ {S[TAT[ISTICS]]} ]
[ {D[IAG[STATS]]} ]
[ {R[ESET]} ]
[ ]
[{;TRACE= } {ON } [,DATA] [,buffsize] ,tracefilename]]
[ {OFF} [,ALL] ]
[ [,PARTIAL] ]
[ [,FULL] ]

"LINKNAME" is a required parameter. The STATUS parameter value
can be specified by preceding it with a comma or semicolon. If
the STATUS parameter is preceded by a semicolon, it is assigned a
keyword value and must be entered as "STATUS=". TRACE must be
specified as a keyword, preceded by a semicolon and entered as
"TRACE=". Either STATUS or TRACE may be specified, but not both.
If neither STATUS or TRACE is specified, the default is STATUS.

PARAMETERS


LINKNAME= Specifies the name of an active data communications link.

@ Specifies all active data communications links.
Other wildcard characters are not allowed.

linkname The name of an active data communications link. This
is the name that was configured for that link by
NMMGR in the datacomm configuration file.

STATUS= Requests status information about the link. This
is the default option. If @ is specified for the
linkname, then the default for STATUS= will be
LINKSTATE; otherwise STATUS=ALL is assumed.

ALL Prints configuration information followed by
link statistics information.

LINKSTATE Prints link name, link type, and link state
information.

CONFIGURATION Prints LINKSTATE information and configuration
information.

STATISTICS Prints LINKSTATE information and various link
statistics, including some accumulated link level
error statistics.

DIAGSTATS Prints LINKSTATE information, followed by link
statistics, which include diagnostic statistics.

RESET Prints LINKSTATE and statistics, then resets
accumulated link statistics counters to 0.

TRACE= Requests trace options for the link. May not be
specified at the same time as STATUS.

ON or OFF Turns link level trace on or off. Either ON or OFF
must be specified. If OFF is specified, the syntax
of any following subparameters is checked, but these
parameters are ignored.

DATA or ALL Used ONLY for LAN links.
Specifies the type of data to be traced. DATA
means trace all read and write requests. ALL means
trace all read, write, control, status, and
exception requests. If neither DATA or ALL is
specified DATA is the default.
PARTIAL or FULL Used ONLY for LAP-B or SDLC links.
Specifies the type of data to be traced. PARTIAL
means all read, write, control, status, and
exception requests are traced. Only the first 16
bytes of data are traced for reads or writes. FULL
means that all read, write, control, status,
exception requests, and the entire data field are
traced. If neither FULL or PARTIAL is specified,
PARTIAL is the default.

buffsize Size in Kbytes of the trace buffer area in memory.
This area is used to buffer trace data before it can
be written to disk. Allowable values are 1 to 16.
The default is 4 for LAN links, and 5 for LAP-B and
SDLC.
tracefilename Designates the name of the disk file where the
trace data is written. If tracefilename is not
specified, a file with the name NMTCnnnn.PUB.SYS
will be supplied automatically, where nnnn varies
from 0 to 9999. If a filename is specified without
group or account names, the current group and
account names of this user are used.


OPERATION

     LINKCONTROL STATUS prints configuration and link level statistics
information about the specified active link. LINKCONTROL TRACE
manages link level tracing for the specified link. Either
LINKCONTROL STATUS or LINKCONTROL TRACE may be specified, but not both.


EXAMPLE(S)

     LINKCONTROL @                        {STATUS=LINKSTATE is default}

LINKCONTROL @;STATUS=ALL {STATUS=ALL for all }
or { active links }
LINKCONTROL @,ALL

LINKCONTROL DTSLINK;STATUS=ALL {STATUS is keyworded}

LINKCONTROL LAPBLINK {STATUS=ALL is default}

LINKCONTROL SYSLINK,RESET {STATUS=RESET}

LINKCONTROL SYSLINK;TRACE=ON,DATA,8 {TRACE is keyworded}

LINKCONTROL SYSLINK;TRACE=OFF

Discussion

The following section describes the data that is output when you issue
the LINKCONTROL command to obtain statistics relating to NS 3000/iX
100VG-AnyLAN Links.


LINKSTATE Parameter Fields

The following is an example of the data that is displayed when you issue
the LINKCONTROL linkname ;STATUS=LINKSTATE command:

Linkname: SYSLINK Linktype: VG8023 Linkstate: CONNECTED

Linkname
The Likname field specifies the name of the link.

Linktype
The Linktype field specifies the type of link, such as
LAP-B, 100VG-802.3, 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:

* Connected
* Not connected


CONFIGURATION Parameter Fields

The CONFIGURATION parameter for 100VG-AnyLAN links displays several
fields in addition to the LINKSTATE parameter field. This is an example
of the data that is displayed when you issue the
LINKCONTROL linkname;STATUS=CONFIGURATION command:

Physical Path: 10/4/8
Current Station Address: 08-00-09-DD-CC-99
Default Station Address: 08-00-09-DD-CC-99
Current Multicast Addresses:
99-00-09-00-00-01 09-00-09-00-00-03 09-00-09-00-00-04 09-00-09-00-00-06

Physical Path
The Physical Path field displays the current physical path for the adapter
card as specified in the NMCONFIG configuration file.

Current Station Address
The Current Station Address field is a display of the six (6) byte
address to which the node is configured to respond. This address is
used whenever frames are sent to the network media.
The default station address is used unless it is overridden in
the NMMGR link configuration screen. If this field is changed, then the
station address of this node is changed. Make sure that you note this
new address in the system manager log.

Default Station Address
The Default Station Address field is the default value for the Current
Station Address described previously. The default station address is
determined by the specific adapter card. It is also printed on a small
label attached to a circuit board on the adapter card. If the adapter
card is changed for any reason, the Default Station Address of this node will change.

Current Multicast Address List
The Current Multicast Addresses field contains a list of all multicast
addresses to which the adapter card responds. The default multicast
address list contains no addresses. If no multicast addresses are enabled,
the follow message is printed:

Current multicast address list is empty

Multicast addresses are configured automatically by the network
transport(s) using the adapter card. The maximum number of multicast
addresses allowed is 16. An example of multicast addresses are:

09-00-09-00-00-01

Probe address

09-00-09-00-00-02

Second probe address

09-00-09-00-00-04

DTC boot address


STATISTICS Parameter Fields

The STATISTICS parameter for 100VG-AnyLAN links displays many fields
in addition to the LINKSTATE parameter fields. The CONFIGURATION
parameter fields are not displayed when this parameter is used. For an
example of the data that is displayed when you issue the
LINKCONTROL linkname;STATUS=STATISTICS command:

Transmit bytes norm 1456044817 Receive bytes norm 5308537515
Transmit byets hipri 62029 Receive bytes hipri 0
Transmits norm 2707747 Receives norm 5302073790
Transmits hipri 712 Receives hipri 0
Transmits no error 2708459 Recv broadcast norm 47068412
Transmits dropped 0 Recv broadcast hipri 0
Trans underruns 0 Recv multicast norm 1300291
Recv overruns 0 Recv multicast hipri 0
Recv deferred 123 Receives no error 664709473
CRC or Maxsize error 0 Recv dropped: addr 16002992
Code or Align error 0 Recv dropped: buffer 262
Link disconnects 0 Recv driooedL dna 0
Link speed 100 Recv dropped: other 24785
Link mode 100VG Secs since clear 6173798
Link training result CONNECTED


*Note: *Some of the parameter descriptions vary according to whether the
adapter card is operating at 100Mbps or 10Mbps speed. For a 100VG
adapter card operating in 10Base-T mode, refer to 100Base-T statistics.


This command displays statistics about data transmitted and received
across the link. Many field values are summations. Over time, the values
in these fields reach their maximum possible value. When this occurs,
these fields can only be reset manually.

Transmit bytes norm
Total number of bytes successfully transmitted onto the medium at normal
priority. This includes unicast, broadcast, and multicast frames.
It also includes frames for which normal priority was requested, but
which were later automatically boosted to demand priority by the
100VG-AnyLAN network. The maximum printable value of this 64-bit field
is 17 digits, or about 99 million Gbytes. In the example above,
1.45 billion bytes were transmitted, or about 1.38 Gbytes.

Transmit bytes hipri
Total number of bytes successfully transmitted onto the medium at high
(demand) priority. This includes unicast, broadcast, and multicast frames.
It does not include frames for which normal priority was originally
requested, but which were later automatically priority-boosted by the
100VG-AnyLAN network. The maximum printable value of this 64-bit field
is 17 digits, or about 99 million Gbytes. In the example above,
62,029 high priority bytes have been transmitted, or about 60K bytes.

Transmits norm
Total number of frames successfully transmitted onto the medium at normal
priority. This includes unicast, broadcast, and multicast frames.
It also includes frames for which normal priority was requested, but which
were later automatically boosted to demand priority by the 100VG-AnyLAN
network. The byte count given by Transmit bytes norm is distributed over
this number of frames. The maximum printable value of this 64-bit field
is 17 digits, or about 99 million billion frames. In the previous example,
2.71million frames were transmitted at normal priority.

Transmits hipri
Total number of frames successfully transmitted onto the medium at high
(demand) priority. This includes unicast, broadcast, and multicast frames.
It does not include frames for which normal priority was originally
requested, but which were later automatically priority-boosted by the
100VG network. The byte count given by Transmit bytes hipri is distributed
over this number of frames. The maximum printable value of this 64-bit
field is 17 digits, or about 99 million billion frames.
In the example above, 712 frames were transmitted at high priority.

Transmits no error
Total number of frames the adapter card reports it successfully transmitted
onto the medium. These adapter card statistics are periodically read, and
are accumulated by the link driver. The total includes all unicast,
broadcast, and multicast frames, at both normal and high (demand) priority.
It should equal the sum of (Transmits norm + Transmits hipri).
The maximum printable value of this 64-bit field is 17 digits, or about
99 million billion frames. In the previous example, 2.71 million frames
were transmitted regardless of priority level.

Transmits dropped
Total number of frames the link driver discarded because the transmit queue
was full, or because the data to be sent was fragmented beyond recognition.
The maximum value of this 32-bit field is 2147483647. It would be unusual
for this statistic to contain a nonzero value.

Trans underruns
Total number of frames aborted by the adapter card during transmission
because the remaining data was not made available to the transmit hardware
fast enough. It indicates unexpected latency on the dedicated internal
bus onboard the adapter card. If this condition occurs, the adapter will
automatically adjust to improve the latency, and retransmit the aborted
frame automatically. The maximum value of this 32-bit field is 2147483647.
For this statistic, a value of less than 3 would be considered normal.

Recv overruns
Total number of address-matched frames that could not be received into the
adapter card, either because prior data was not being removed by the
receive hardware fast enough, or because their size exceeded the maximum
frame size. May indicate unexpected latency on the dedicated internal bus
onboard the adapter card, which cannot be automatically adjusted by the
link driver. The maximum value of this 32-bit field is 2147483647.
It would be unusual for this statistic to contain a nonzero value.

Recv deferred
Number of times an address-matched receive frame was temporarily held
(queued) by the link driver, because of a momentary lack of DMA resources.
Once those resources became available, the frame was automatically
transferred to the host. The maximum printable value of this 64-bit field
is 17 digits, or about 99 million billion frames.
In the previous example, 123 frames were temporarily held.

CRC or Maxsize error
Number of cyclic redundancy check (CRC) errors or oversized frames that
were seen during reception by the link. A CRC error indicates that the
frame was checked using CRC-32 frame-checking, but that the value obtained
by the CRC did not match the CRC value contained at the end of the frame.
CRC errors do not include frames having alignment or coding errors.
Oversized frames are those longer than 1518 bytes. These adapter card
statistics are periodically read, and are accumulated by the link driver.
The maximum value of this 32-bit field is 2147483647. A nonzero value in
this statistic could indicate a defective cable, adapter, or hub, a loose
connection, presence of severe electrical noise along the cable path,
or a misbehaving application, adapter, or hub at the transmission end.

Code or Align error
Number of frames received with an alignment error (not an even multiple
of 4 bits of data) or code errors (an error signal was received from
the 100VG-AnyLAN receive hardware). These adapter card statistics are
periodically read, and are accumulated by the link driver. The maximum
value of this 32-bit field is 2147483647. If alignment errors occur
frequently, one of the following may be the cause:

* A 100VG-AnyLAN adapter card is not operating to within 802.12
specifications.

* A 100VG-AnyLAN hub is performing poorly.

* The 100VG-AnyLAN cable is not CAT-3 or CAT-5 grade.

* A section of 100VG-AnyLAN cable contains wire pairs which are not
properly twisted, paired, or of equal length.

Link disconnects
Number of times the link driver noticed the link had previously been
established, but was no longer up. This may occur because the cable was
unplugged, the hub was powered off, the hub automatically requested a
reconnect, or normally (at link shutdown time). This total does not
include repetitive, failed attempts by the link driver to reestablish
the link. The maximum value of this 32-bit field is 2147483647.

Link speed
Maximum link speed (either 100 or 10) in millions of bits per second,
the link is currently configured to operate at. When displaying a
100VG-AnyLAN link operating in 100VG-AnyLAN mode, this value will
always be 100. When a 100VG-AnyLAN link is operating in 10Base-T mode,
this value will always be 10.

Link mode
Electrical mode the link is currently operating at. When displaying
a 100VG-AnyLAN link operating in 100VG-AnyLAN mode, this value will
always be "100VG-AnyLAN". When a 100VG-AnyLAN link is operating in
10Base-T mode, this value will be "10Base-T".

Link training result
The result of the last automatic 100VG-AnyLAN "link training" operation
performed during link establishment. If the cable is connected to an
operational 100VG-AnyLAN hub port, the link is configured for 100VG-AnyLAN
operation in NMCONFIG, and the link driver has been started, this value
should be "CONNECTED". Most other values indicate a problem with the hub port,
the connection to that 100VG-AnyLAN hub port, or the cable grade is not CAT-3 or CAT-5.

Receive bytes norm
Total number of bytes successfully received over the medium at normal
priority. This includes unicast, multicast, broadcast, and link
training frames. It does not include frames received by the adapter
card but dropped because no upper layer protocol had requested those
frames, or because the link was disconnected. The maximum value of this
64-bit field is 17 digits, or about 99 million Gbytes. In the example
above, 5.30 billion bytes were received, or about 5.06 Gbytes.

Receive bytes hipri
Total number of bytes successfully received over the medium at high
(demand) priority. This includes unicast, multicast, and broadcast frames.
It also includes frames for which normal priority was originally requested
by the sender, but which were later automatically priority-boosted by the
100VG-AnyLAN network. It does not include frames received by the adapter
card but dropped because no upper layer protocol had requested those frames,
or because the link was disconnected. The maximum printable value of this
64-bit field is 17 digits, or about 99 million Gbytes. In the example above,
no high priority data has been received.

Receives norm
Total number of unicast frames (addressed to this specific adapter card)
which were successfully received over the medium at normal priority and
forwarded to an upper layer protocol such as IP.
This includes link training frames received from the 100VG-AnyLAN hub.
It does not include unicast frames received but dropped for any reason.
The maximum printable value of this 64-bit field is 17 digits, or about
99 million billion frames. In the previous example, 2.07 million unicast
frames were received at normal priority and forwarded to upper layers.

Receives hipri
Total number of unicast frames (addressed to this specific adapter card)
which were successfully received over the medium at high (demand)
priority and forwarded to an upper layer protocol such as IP.
This includes unicast frames for which normal priority was
originally requested by the sender, but which were later automatically
priority-boosted by the 100VG-AnyLAN network. It does not include
unicast frames received but dropped for any reason. The maximum
printable value of this 64-bit field is 17 digits, or about 99 million
billion frames. In the previous example, no frames have been received at
high priority.

Recv broadcast norm
Total number of frames addressed to a broadcast address which were
successfully received over the medium at normal priority and forwarded
to an upper layer protocol such as ARP. This does not include broadcast
frames received but dropped for any reason. The maximum value of this
64-bit field is 17 digits, or about 99 million billion frames.
In the previous example, 47.1 million broadcast frames were received
at normal priority and forwarded to upper layers.

Recv broadcast hipri
Total number of frames addressed to a broadcast address which were
successfully received over the medium at high (demand) priority and
forwarded to an upper layer protocol such as ARP.
This includes broadcast frames for which normal priority was originally
requested by the sender, but which were later automatically
priority-boosted by the 100VG-AnyLAN network. It does not include
broadcast frames received but dropped for any reason. The maximum
printable value of this 64-bit field is 17 digits, or about 99 million
billion frames. In the previous example, no frames have been received at
high priority.

Recv multicast norm
Total number of frames addressed to a multicast address which were
successfully received over the medium at normal priority and forwarded
to an upper layer protocol such as PROBE. This does not include multicast
frames received but dropped for any reason.
Upper layer protocols register desired multicast addresses with the link
driver during initialization. The maximum printable value of this 64-bit
field is 17 digits, or about 99 million billion frames. In the previous
example, 1.30 million multicast frames were received at normal priority
and forwarded to upper layers.

Recv multicast hipri
Total number of frames addressed to a multicast address which were
successfully received over the medium at high (demand) priority and
forwarded to an upper layer protocol such as PROBE.
This includes multicast frames for which normal priority was
originally requested by the sender, but which were later automatically
priority-boosted by the 100VG-AnyLAN network. It does not include
multicast frames received but dropped for any reason. Upper layer
protocols register desired multicast addresses with the link driver
during initialization. The maximum printable value of this 64-bit field
is 17 digits, or about 99 million billion frames. In the previous
example, no frames have been received at high priority.

Receives no error
Total number of frames the adapter card reports it successfully received
over the medium. These adapter card statistics are periodically read,
and are accumulated by the link driver. This includes both normal and
high (demand) priority frames. It does not include any frames the
adapter card detected errors against. The total should approximate the
sum of all frames forwarded to upper layer protocols, plus all frames
dropped for any reason. The maximum printable value of this 64-bit field
is 17 digits, or about 99 million billion frames. In the previous example,
6.64 million frames were received successfully by the adapter card,
then either forwarded or dropped.

Recv dropped: addr
Total number of frames received by the adapter
card, but dropped because no upper layer protocol had requested future
reception of those frames, or because that protocol unbound itself from
the link while the received frame was still in motion. Older,
intelligent adapter cards can invisibly receive and drop these frames,
often without ever reporting them as statistics. But today's adapters
are not intelligent, and require link driver involvement. For users
unfamiliar with seeing it, this statistic may seem excessive. But it is
important because it gives an indication of the amount of unnecessary
traffic present on the network segment to which the adapter card is
connected. High values may indicate a need to resegment the network,
since systems and their adapters are spending a large amount of time and
resources recognizing and dropping frames they do not care to see. High
volumes of such traffic can also limit network bandwidth. The maximum
printable value of this 64-bit field is 17 digits, or about 99 million
billion frames. In the previous example, out of 66.4 million frames
received, 16.0 million have been dropped based on address: about 24% of
all frames received are then being dropped. This level would be
considered typical or perhaps a little high.

Recv dropped: buffer
Total number of frames received from the adapter card, but dropped
because no data buffers were available from the upper layer protocol
requesting to receive these frames. This is a relatively common
occurrence, amounting to flow control for all protocols sharing those
buffers. Many protocols include built-in mechanisms for detecting lost
frames and requesting their retransmission from the remote side.
The maximum value of this 32-bit field is 2147483647. In the previous
example, out of 66.4 million frames received, 262 have been dropped
for lack of buffer resources; any similar level would be considered normal.

Recv dropped: dma
The link driver design now queues frames under conditions of low DMA
resources, so this statistic is now obsolete, should never contain a
nonzero value, and may be deleted in a future release.

Recv dropped: other
Sum total number of frames received from the adapter card, but dropped
because: an upper layer protocol error was returned; the required
address format was not supported; the frame arrived while the link
driver was in an unusual state; or for perfect multicast filtering
reasons. The maximum value of this 32-bit sum is 2147483647. In the
previous example, 24785 frames have been dropped for one or more of
the reasons listed; this number would be considered high, and further
investigation might be needed if it appears to be impacting any applications.

Secs since clear
The number of seconds elapsed since statistics were last reset via the
LINKCONTROL linkname; STATUS=RESET command. This gives the sample time
over which the displayed statistics have been collected. Per-time-unit
figures may then be calculated if desired. The maximum value of this
32-bit field is 2147483647, or about 68 years.