Abstract In CCITT documents, frame relay is referred to as an ISDN frame mode bearer service. Layer 3 messages are carried across a frame relay network in frames and, compared with X.25 for instance, the layer 2 protocol in the network is minimal. Frame relay networks are expected to carry a mixture of different types of traffic and a suggested traffic classification scheme is given in this paper. Also considered are the important issues of buffer management and congestion control and how these might be implemented in frame relay network nodes. Most of these concerns relate to the U (user) plane and, unless otherwise stated, the paper concentrates exclusively on traffic management in the U-plane.