An apparatus that is a first multi-link device (MLD) or a component of the first MLD is caused to obtain information about a first relay MLD through a first communication link. The first relay MLD is used to relay information transmitted by the first MLD to a second MLD through a second communication link. The apparatus is also caused to send a first request message to the first relay MLD and the second MLD through the first communication link. The first request message is used to request to establish a second communication link between the first MLD and the first relay MLD and a second communication link between the second MLD and the first relay MLD. The frequency band on which the first communication link operates is lower than a frequency band on which the second communication link operates.