Handling Two-Way TCP Traffic in Asymmetric Networks

Abstract

Abstract. The TCP congestion control protocol is mainly designed for bandwidth symmetric paths. As two-way asymmetric connections will probably become common case in the future with the widespread use of ADSL, satellites and other high-speed technologies, it is important to make sure that congestion will be properly handled in these environments. To this end, we propose in this paper a new Adaptive Class-based Queuing mechanism called ACQ for handling two-way TCP trac over links that exhibit bandwidth asymmetry. ACQ runs at the entry of the slow link and relies on two separate classes, one for ACK packets and one for Data packets. ACQ proposes to adapt the weights of both classes according to the crossing trac in order to maximize some utility function dened by the user or the network operator. We show by simulations that our mechanism is able to reach a good utilization of the available resources, managing then to maximize the satisfaction of the user of such asymmetric connections.

Adaptive Scheduling of Data Transfer in P2P Applications over Asymmetric Networks

“…An effective network layer approach is to implement priority queuing in the network device connected to the uplink. The principle is to schedule packets from the receiver based on their packet type and gives higher priority to Ack packets [3][4][5]. Thus even under heavy uplink data traffic Ack packets will still not be affected.…”

Protecting Download Traffic from Upload Traffic over Asymmetric Wireless Links

“…We attempted various TCP configurations, such as TCP window size, delay ACK, selective ACK, buffer size, and TCP autotuning to address this problem, but no setting choices were successful. Some studies have addressed TCP upload or download throughput degradation in asymmetric links, including ADSL, cable, and satellite [14][15][16][17][18][19]. However, the proposed solutions generally impose additional overhead of maintaining separate packet queues [15][16][17][18][19][20][21][22][23][24], modifying TCP protocols or parameters [25,26], or tracking per-flow traffic statistics [18] on access points (i.e., base stations) or mobile stations.…”