Abstract: A method for communication includes establishing a full-duplex communication link between first and second nodes. The link includes multiple first lanes for conveying first communication traffic in a first link direction and multiple second lanes for conveying second communication traffic in a second link direction. Signals are exchanged between the first and second nodes to indicate a requested change in lane activity in the first link direction. Responsively to the signals, a number of the first lanes that are active is changed so that the first node conveys the first communication traffic to the second node over a first number of the first lanes, while the second node conveys the second communication traffic to the first node over a second number of the second lanes, which is different from the first number.