Command Reference Guide

254 ● looptest 3Com Router 5000 Family and Router 6000 Family
Command Reference
looptest
Purpose Use the looptest command to test whether an interface or line is in a loop.
Syntax looptest [ -c count | -p { pattern | special { ascending | descending |
random } } | -s packetsize | -t timeout ] * interface type number
Parameters -c count
Number of test packets sending attempts. Valid values
are 1 to 4,294,967,295.
If not specified, the default is 5.
-p pattern
Test pattern, consisting of a hexadecimal string in the
range 0 to FFFFFFFF, (for example ff).
If not specified, the default test pattern is 0x55
interleaved with 0xAA.
ascending
Pads each test packet byte-by-byte with sequences
from 0x00 to 0xff cyclically in ascending order.
descending
Pads each test packet byte-by-byte with sequences
from 0x00 to 0xff cyclically in descending order.
random
Pads each test packet byte-by-byte with a sequence in
the range 0x00 to 0xff.
-s packetsize
Test packet size with the 12-byte header excluded. It
ranges from 0 to 1688 bytes and defaults to 52 bytes.
-t timeout
Sets the timeout waiting for receiving a sent test
packet.Valid values are 0 to 65,535 milliseconds.
If not specified, the default is 2000 milliseconds.
interface type number
Specifies an interface by its type and number.
Example Test whether interface Serial 1/0/0 and its connected line is in a loop.
<3Com > looptest interface serial 1/0/0
LOOPTEST Serial1/0/0: 52 data bytes, press CTRL_C to break
Receive from Serial1/0/0: bytes=52 sequence=1 time=1 ms
Receive from Serial1/0/0: bytes=52 sequence=2 time=1 ms
Receive from Serial1/0/0: bytes=52 sequence=3 time=1 ms
Receive from Serial1/0/0: bytes=52 sequence=4 time=1 ms
Receive from Serial1/0/0: bytes=52 sequence=5 time=1 ms
--- Serial1/0/0 looptest statistics ---
5 packet(s) transmitted
5 packet(s) received
0 packet(s) lost
0 packet(s) error
0.00% packet lost
0.00% packet error
round-trip min/avg/max = 1/1/1 ms
conclusion: loopback