R3303-HP HSR6800 Routers Interface Configuration Guide

12
Enabling loopback detection on an Ethernet interface
If a device receives a packet that it sent, a loop has occurred to the device. Loops might cause broadcast
storms, which degrade network performance. You can use this feature to detect whether a loop has
occurred.
• Single-port loopback—Single-port loopback occurs when an interface receives a packet that it sent
and the receiving interface is the same as the sending interface, as shown in 错误！未找到引用
源。.
• Multi-port loopback—Multi-port loopback occurs when a device receives a packet that it sent but
the receiving interface might not be the sending interface, as shown in Figure 3. Su
pport for
multi-port loopback detection depends on your device model.
Figure 2 Single-port loopback
Figure 3 Multi-port loopback
You can enable loopback detection to detect loops on an interface and, if the interface supports the
loopback-detection action command, configure the protective action to take on the receiving interface
when a loop is detected, for example, to shut down the interface. Depending on whether a protective
action is configured, the device takes the actions in Table 1 to alle
viate the impact of the loop condition.
Table 1 Actions to take upon detection of a loop condition
Port type
Actions
No
p
rotective action is confi
g
ured A
p
rotective action is confi
g
ured
Access port
• Place the receiving interface in controlled
mode. The interface discards all incoming
packets, but still forwards outgoing packets.
• Generate traps.
• Delete all MAC address entries of the
interface.
• Perform the configured protective
action.
• Generate traps and log messages.
• Delete all MAC address entries of the
interface.