syncloop(1M)
NAME
syncloop - synchronous serial loopback test program
SYNOPSIS
/usr/sbin/syncloop [-cdlstv] device
DESCRIPTION
The syncloop command performs several loopback tests that
are useful in exercising the various components of a serial
communications link.
Before running a test, syncloop opens the designated port
and configures it according to command line options and the
specified test type. It announces the names of the devices
being used to control the hardware channel, the channel
number (ppa) corresponding to the device argument, and the
parameters it has set for that channel. It then runs the
loopback test in three phases.
The first phase is to listen on the port for any activity.
If no activity is seen for at least four seconds, syncloop
proceeds to the next phase. Otherwise, the user is informed
that the line is active and that the test cannot proceed,
and the program exits.
In the second phase, called the "first-packet" phase, syn-
cloop attempts to send and receive one packet. The program
will wait for up to four seconds for the returned packet. If
no packets are seen after five attempts, the test fails with
an excoriating message. If a packet is returned, the result
is compared with the original. If the length and content do
not match exactly, the test fails.
The final phase, known as the "multiple-packet" phase,
attempts to send many packets through the loop. Because the
program has verified the integrity of the link in the
first-packet phase, the test will not fail after a particu-
lar number of timeouts. If a packet is not seen after four
seconds, a message is displayed. Otherwise, a count of the
number of packets received is updated on the display once
per second. If it becomes obvious that the test is not
receiving packets during this phase, the user may wish to
stop the program manually. The number and size of the pack-
ets sent during this phase is determined by default values,
or by command line options. Each returned packet is compared
with its original for length and content. If a mismatch is
detected, the test fails. The test completes when the
required number of packets have been sent, regardless of
errors.
After the multiple-packet phase has completed, the program
displays a summary of the hardware event statistics for the
channel that was tested. The display takes the following
form:
CRC errors Aborts Overruns Underruns In<-Drops-> Out
0 0 0 0 0 0
This is followed by an estimated line speed, which is an
approximation of the bit rate of the line, based on the
number of bytes sent and the actual time that it took to
send them.
OPTIONS
The options for syncloop are described in the following
table:
Option Parameter Default Description
-c packet_count 100 Specifies the number of pack-
ets to be sent in the
multiple-packet phase.
-d hex_data_byte random Specifies that each packet
will be filled with bytes
with the value of
hex_data_byte.
-l packet_length 100 Specifies the length of each
packet in bytes.
-s line_speed 9600 Bit rate in bits per second.
-v Sets verbose mode. If data
errors occur, the expected
and received data is
displayed.
-t test_type none A number, from 1 to 4, that
specifies which test to per-
form. The values for
test_type are as follows: 1:
Internal loopback test. Port
loopback is on. Transmit and
receive clock sources are
internal (baud rate genera-
tor). 2: External loopback
test. Port loopback is off.
Transmit and receive clock
sources are internal.
Requires a loopback plug
suitable to the port under
test. 3: External loopback
test. Port loopback is off.
Transmit and receive clock
sources are external (modem).
Requires that one of the
local modem, the remote
modem, or the remote system
be set in a loopback confi-
guration. 4: Test using
predefined parameters. User
defines hardware configura-
tion and may select port
parameters using the
syncinit(1M) command.
All numeric options except -d are entered as decimal numbers
(for example, -s 19200). If you do not provide the -t
test_type option, syncloop prompts for it.
EXAMPLES
Example 1: A sample display of using the syncloop command.
In the following command syncloop uses a packet length of
512 bytes over the first CPU port:
example# syncloop -l 512 zsh0
In response to the above command, syncloop prompts you for
the test option you want.
The following command performs an internal loopback test on
the first CPU port, using 5000 packets and a bit rate of
56Kbps:
example# syncloop -t 1 -s 56000 -c 5000 zsh0
ATTRIBUTES
See attributes(5) for descriptions of the following attri-
butes:
____________________________________________________________
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
|_____________________________|_____________________________|
| Availability | SUNWcsu |
|_____________________________|_____________________________|
SEE ALSO
syncinit(1M), syncstat(1M), attributes(5), zsh(7D)
DIAGNOSTICS
device missing minor device number
The name device does not end in a decimal number that
can be used as a minor device number.
invalid packet length: nnn
The packet length was specified to be less than zero
or greater than 4096.
poll: nothing to read
poll: nothing to read or write.
The poll(2) system call indicates that there is no
input pending and/or that output would be blocked if
attempted.
len xxx should be yyy
The packet that was sent had a length of yyy, but was
received with a length of xxx.
nnn packets lost in outbound queueing
nnn packets lost in inbound queueing
A discrepancy has been found between the number of
packets sent by syncloop and the number of packets the
driver counted as transmitted, or between the number
counted as received and the number read by the pro-
gram.
WARNINGS
To allow its tests to run properly, as well as prevent dis-
turbance of normal operations, syncloop should only be run
on a port that is not being used for any other purpose at
that time.
Man(1) output converted with
man2html