1syncloop(1M) System Administration Commands syncloop(1M)
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6 syncloop - synchronous serial loopback test program
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9 /usr/sbin/syncloop [-cdlstv] device
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13 The syncloop command performs several loopback tests that are useful in
14 exercising the various components of a serial communications link.
15 Before running a test, syncloop opens the designated port and config‐
18 ures it according to command line options and the specified test type.
19 It announces the names of the devices being used to control the hard‐
20 ware channel, the channel number (ppa) corresponding to the device
21 argument, and the parameters it has set for that channel. It then runs
22 the loopback test in three phases.
23 The first phase is to listen on the port for any activity. If no
26 activity is seen for at least four seconds, syncloop proceeds to the
27 next phase. Otherwise, the user is informed that the line is active and
28 that the test cannot proceed, and the program exits.
29 In the second phase, called the "first-packet" phase, syncloop attempts
32 to send and receive one packet. The program will wait for up to four
33 seconds for the returned packet. If no packets are seen after five
34 attempts, the test fails with an excoriating message. If a packet is
35 returned, the result is compared with the original. If the length and
36 content do not match exactly, the test fails.
37 The final phase, known as the "multiple-packet" phase, attempts to send
40 many packets through the loop. Because the program has verified the
41 integrity of the link in the first-packet phase, the test will not fail
42 after a particular number of timeouts. If a packet is not seen after
43 four seconds, a message is displayed. Otherwise, a count of the number
44 of packets received is updated on the display once per second. If it
45 becomes obvious that the test is not receiving packets during this
46 phase, the user may wish to stop the program manually. The number and
47 size of the packets sent during this phase is determined by default
48 values, or by command line options. Each returned packet is compared
49 with its original for length and content. If a mismatch is detected,
50 the test fails. The test completes when the required number of packets
51 have been sent, regardless of errors.
52 After the multiple-packet phase has completed, the program displays a
55 summary of the hardware event statistics for the channel that was
56 tested. The display takes the following form:
57 CRC errors Aborts Overruns Underruns In<-Drops-> Out
59 0 0 0 0 0 0
60 This is followed by an estimated line speed, which is an approximation
65 of the bit rate of the line, based on the number of bytes sent and the
66 actual time that it took to send them.
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69 The options for syncloop are described in the following table:
70 Option Parameter Default Description
75 -c packet_count 100 Specifies the number of pack‐
76 ets to be sent in the multi‐
77 ple-packet phase.
78 -d hex_data_byte random Specifies that each packet
79 will be filled with bytes
80 with the value of
81 hex_data_byte.
82 -l packet_length 100 Specifies the length of each
83 packet in bytes.
84 -s line_speed 9600 Bit rate in bits per second.
85 -v Sets verbose mode. If data
86 errors occur, the expected
87 and received data is dis‐
88 played.
89 -t test_type none A number, from 1 to 4, that
90 specifies which test to per‐
91 form. The values for
92 test_type are as follows: 1:
93 Internal loopback test. Port
94 loopback is on. Transmit and
95 receive clock sources are
96 internal (baud rate genera‐
97 tor). 2: External loopback
98 test. Port loopback is off.
99 Transmit and receive clock
100 sources are internal.
101 Requires a loopback plug
102 suitable to the port under
103 test. 3: External loopback
104 test. Port loopback is off.
105 Transmit and receive clock
106 sources are external (modem).
107 Requires that one of the
108 local modem, the remote
109 modem, or the remote system
110 be set in a loopback configu‐
111 ration. 4: Test using prede‐
112 fined parameters. User
113 defines hardware configura‐
114 tion and may select port
115 parameters using the
116 syncinit(1M) command.
117 All numeric options except -d are entered as decimal numbers (for exam‐
121 ple, -s 19200). If you do not provide the -t test_type option, syncloop
122 prompts for it.
123
125 Example 1 A sample display of using the syncloop command.
126 In the following command syncloop uses a packet length of 512 bytes
129 over the first CPU port:
130 example# syncloop -l 512 zsh0
133 In response to the above command, syncloop prompts you for the test
138 option you want.
139 The following command performs an internal loopback test on the first
143 CPU port, using 5000 packets and a bit rate of 56Kbps:
144 example# syncloop -t 1 -s 56000 -c 5000 zsh0
147
151 See attributes(5) for descriptions of the following attributes:
152 ┌─────────────────────────────┬─────────────────────────────┐
157 │ ATTRIBUTE TYPE │ ATTRIBUTE VALUE │
158 ├─────────────────────────────┼─────────────────────────────┤
159 │Availability │SUNWcsu │
160 └─────────────────────────────┴─────────────────────────────┘
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163 syncinit(1M), syncstat(1M), attributes(5), zsh(7D)
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166 device missing minor device number
167 The name device does not end in a decimal number that can be used
169 as a minor device number.
170 invalid packet length: nnn
173 The packet length was specified to be less than zero or greater
175 than 4096.
176 poll: nothing to read
179 poll: nothing to read or write.
184 The poll(2) system call indicates that there is no input pending
186 and/or that output would be blocked if attempted.
187 len xxx should be yyy
190 The packet that was sent had a length of yyy, but was received with
192 a length of xxx.
193 nnn packets lost in outbound queueing
196 nnn packets lost in inbound queueing
201 A discrepancy has been found between the number of packets sent by
203 syncloop and the number of packets the driver counted as transmit‐
204 ted, or between the number counted as received and the number read
205 by the program.
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209 To allow its tests to run properly, as well as prevent disturbance of
210 normal operations, syncloop should only be run on a port that is not
211 being used for any other purpose at that time.
212SunOS 5.11 9 Mar 1993 syncloop(1M)