R2511-HP MSR Router Series Interface Command Reference(V5)

70
[Sysname] interface serial 2/0
[Sysname-Serial2/0] loopback
looptest
Use looptest to perform a loop test on a synchronous serial interface created for E1, T1, E1-F, or T1-F.
Syntax
looptest [ -c count | -p { pattern | special { ascending | descending | random } } | -s packetsize | -t
timeout ] * interface type number
Views
Any view
Parameters
-c count: Sets the number of test packets, in the range of 1 to 1 to 4294967295. The default number is
5.
-p pattern: Sets the padding content for test packets, which is a hexadecimal number in the range of 0
to FFFFFFFF. For example, -p ff pads FF to all test packets. By default, 0x55 and 0xAA are padded
alternately.
ascending: Pads test packets with a hexadecimal number from 0x00 to 0xff in turn.
descending: Pads test packets with a hexadecimal number from 0xff to 0x00 in turn.
random: Pads test packets with a hexadecimal number from 0xff to 0x00 at random.
-s packetsize: Sets the size of test packets (excluding the 12-byte packet header), in the range of 0 to
1688 bytes. The default size is 52 bytes.
-t timeout: Sets the timeout time for receiving looped-back test packets, in the range of 0 to 65535
milliseconds. The default timeout time is 2000 milliseconds.
interface type number: Specifies an interface.
Usage guidelines
Use looptest to detect loops on interfaces. The system returns the following line quality information:
• Information about each test packet. If a test packet is looped back, the number of bytes, sequence
number, and delay are displayed for the test packet. If a test packet is not looped back before the
timeout timer expires, the system displays " Wait time out."
• Statistics for all test packets, including the numbers of sent, received, lost, and error packets,
percentages for error and lost packets, and the conclusion.
If the line speed is slow, increase the timeout time.
Examples
# Perform a loop test on Serial 1/0/0.
<Sysname> 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