I am having problems with the function of loopback-detect.it does not work in this case:
If an interface MA5600 has been added to VLANs in untagged mode, the interface sends one copy of untagged detection packet regardless of how many VLANs the interface has been added to. The untagged detection packets will be discarded on the link, so loopback detection cannot be performed on the network. In this situation, loopback detection must be configured in these VLANs.
If an interface has been added to VLANs in tagged mode, loopback detection must be enabled in specified VLANs, and the interface sends the loopback detection packets of the VLAN that contains the interface and has loopback detection enabled.
After VLAN IDs are specified, the interface sends one copy of untagged loopback detection packets and multiple copies of tagged loopback detection packets with the specified VLAN tags.
interface Ethernet0/0/10
port link-type access
port default vlan 100
loopback-detect packet vlan 100
loopback-detect enable
undo ntdp enable
undo ndp enable
port-security enable
port-security protect-action protect
port-security max-mac-num 5
multicast-suppression 5
broadcast-suppression 10
traffic-pppoe any d0d0-fd50-7e90
interface GigabitEthernet0/0/2
port link-type trunk
undo port trunk allow-pass vlan 1
port trunk allow-pass vlan 100 1083 to 1084
loopback-detect packet vlan 100
loopback-detect enable
#
right switch:
interface GigabitEthernet0/0/2
port link-type trunk
port trunk allow-pass vlan 100
loopback-detect packet vlan 100
loopback-detect enable
interface Ethernet0/0/1
port link-type access
port default vlan 100
loopback-detect packet vlan 100
loopback MA5600T -detect enable