A method for cellular network operation includes establishing a transport network communication link in a cellular network between first and second infrastructure cellular entities. A first transport link control function is established within the first infrastructure cellular entity, and a pair transport link control function is established within the second infrastructure cellular entity. Data packets are transmitted through the first and second transport link control functions on the transport network communication link while allocating sequence numbers by the first transport link control function to the transmitted data packets. The pair transport link control function detects, based on the sequence numbers, a loss of a data packet transmitted by the first transport link control function and transmits a status report to the first transport link control function. The forwarding of user traffic from the first infrastructure cellular entity to the second infrastructure cellular entity is controlled responsively to the reports.