TP-Link T2600G Series User Manual page 1007

Configuring OAM
5) When Remote Loopback is finished, Switch A sends a Loopback Control OAMPDU to
disable the remote loopback mode on Switch B.
6) Switch B receives the Loopback Control OAMPDU and exits remote loopback mode.
Besides, Switch B sends an Information OAMPDU to inform its state updating.
TP-Link switches can act as Switch A and initiate Remote Loopback request.
Ethernet OAM
User Guide 978