Loop Detection Interval; Loop Protection Actions; Port Status Auto Recovery - H3C S12500X-AF Series Configuration Manual

The inner frame header for loop detection contains the following fields:
•
Code—Protocol sub-type, which is 0x0001, indicating the loop detection protocol.
•
Version—Protocol version, which is always 0x0000.
•
Length—Length of the frame. The value includes the inner header, but excludes the Ethernet
header.
•
Reserved—This field is reserved.
Frames for loop detection are encapsulated as TLV triplets.
Table 12 TLVs supported by loop detection
TLV
End of PDU
Device ID
Port ID
Port Name
System Name
Chassis ID
Slot ID
Sub Slot ID

Loop detection interval

Loop detection is a continuous process as the network changes. Loop detection frames are sent at
the loop detection interval to determine whether loops occur on ports and whether loops are
removed.

Loop protection actions

When the device detects a loop on a port, it generates a log but performs no action on the port by
default. You can configure the device to take one of the following actions:
•
Block—Disables the port from learning MAC addresses and blocks the port.
•
No-learning—Disables the port from learning MAC addresses.
•
Shutdown—Shuts down the port to disable it from receiving and sending any frames.

Port status auto recovery

When the device configured with the block or no-learning loop action detects a loop on a port, it
performs the action and waits three loop detection intervals. If the device does not receive a loop
detection frame within three loop detection intervals, it performs the following operations:
•
Automatically sets the port to the forwarding state.
•
Notifies the user of the event.
When the device configured with the shutdown action detects a loop on a port, the following events
occur:
The device automatically shuts down the port.
1.
Description
End of a PDU.
Bridge MAC address of the sending device.
ID of the PDU sending port.
Name of the PDU sending port.
Device name.
Chassis ID of the sending port.
Slot ID of the sending port.
Sub-slot ID of the sending port.
133
Remarks
Optional.
Required.
Optional.
Optional.
Optional.
Optional.
Optional.
Optional.