A network traffic manager receives, from an ingress port, a cell of a packet destined for an egress port. Upon determining that a number of cells of the packet stored in a buffer queue meets a threshold value, the manager checks whether the ingress port has been assigned a token corresponding to the queue. Upon determining that the ingress port has been assigned the token, the manager determines whether other cells of the packet are stored in the buffer, in response to which the manager stores the received cell in the buffer, and stores linking information for the received cell in a receive context for the packet. When all cells of the packet have been received, the manager copies linking information for the packet cells from the receive context to the buffer queue or a copy generator queue, and releases the token from the ingress port.