Single Loop Test Method; Configuring Single-Port Loop Test; Table 437 Set Loop Detect Port Command - Zte ZXR10 2920 User Manual

ZXR10 2920/2928/2952
Features of
Singly Port
Loop
Principle of
Single Port
Loop Test
Source MAC
address
Port Number
Discimination
Field
Purpose
Steps
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Access Switch User Manual （Volume I）

Single Loop Test Method

Single-port loop test is to check whether a loop exists in the
ports of the switch.
errors in learning MAC addresses and may easily cause a
broadcast storm.
down. Starting the single-port loop test and disabling the port
with loop can efficiently avoid the influence caused by port loop.
Working principle of single-port loop test, switch sends a test
message on a port, if the test message comes back on the port
without any changes or just is added a tag, it indicates that a
loop exists on this port.
The switch sends a test packet through a port.
packet is received through the port without any change (or only
a tag is attached), it indicates that a loop exists in this port.
The test packet sent by the switch includes the following three
parameters:
It indicates the MAC address of the switch.
each switch is unique.
Port numbers correspond to the numbers of the ports on the
switch one by one.
For each switch, the digital signature of each port is different.
When three parameters in the test packet sent through port are
same as those in the test packet received through the port, a
port loop absolutely exists.

Configuring Single-Port Loop Test

This topic describes the configuration of single-port loop test.
For the configuration of single-port loop test,
following steps.
1. To enable/disable loop test function of specified port,
command set loopdetect port <portlist> {enable|disable}
in global config mode.
T 4 3 7 S L
A B L E E T
Format
set loopdetect
port <portlist>
{enable|disable
Result: This enable/disable loop test function of specified
port.
Note: By default, port loop test function is disabled.
If such a loop exists,
In worse cases, switch and network may be
This is shown in Table 437.
D P C
O O P E T E C T O R T O M M A N D
Mode
global config
it may result in
If this test
The MAC address of
perform the
use
Function
This enable/disable
loop test function of
specified port