User's Manual

Table Of Contents
368
Users Manual of CS-6306R
ages.
Nolearn: means to forbid the port to learn MAC addresses. When loopback is detected, the port will not
conduct MAC address learning any more and at the same time the MAC address table of this port ages.
shutdown: Means to close the port. When loopback is detected, except that trap message will be transmitted
and the port’s MAC address table ages, the port will be automatically closed and it cannot forward packets
any more until the err-disable-recover time.
Trap: It means that the port only reports alarm. When loopback is detected, the port only reports alarm and
ages its MAC address table without any further action.
When the port is in block state, it cannot forward incoming packets and at the same time it transmits loopback
detection packets continuously. When loopback disappears, the port will recover automatically. In default
settings, if a port has not received the already transmitted loopback detection packet within 10 seconds, it is
regarded that loopback vanishes.
In block state, the port protocol is down; in shutdown state, the port’s link is down directly.
39.1.3.6 Configuring the Destination MAC Address of Loopback Detection Packet
Command Purpose
[no] loopback-detection dest-mac
Mac-address
Configures the destination MAC address of
loopback detection packet.
The default destination MAC address of loopback detection packet is 01-80-C2-00-00-0a. If you have set
other destination MAC, it will be used as the destination MAC address of loopback detection packet.
39.1.3.7 Configuring Loopback to Exist on a Port by Default
Command Purpose
[no] loopback-detection existence
Configures loopback to exist on a port by
default.
When a port is up and port loopback detection takes effect, the command above is used to set whether
loopback exists on this port. When a port is in shutdown state, this port is not suitable to set to have loopback,
for the port in shutdown state cannot forward packets. The default settings is that loopback does not exist in a
port.
39.1.3.8 Displaying the Configuration of Global Loopback Detection
Command Purpose
show loopback-detection
Displays the configuration of global loopback detection.
This command is used to display the information about global loopback detection configuration, including
global configuration, whether loopback exists on each port, and some ports’ configurations.