Efficient congestion control mechanism for flow‐aware networks

Abstract

Transmission based on flows becomes more and more popular in teleinformatics networks. To guarantee proper quality of service, to enable multipath transmissions, or just to increase transmission effectiveness in a network, traffic should be sent as flows. Flow-aware networking architecture is one of the possible concepts to realize flow-based transmissions. In this paper, the efficient congestion control mechanism (ECCM) is proposed to improve transmission in flow-aware networks (FAN). The mechanism makes it possible to minimize acceptance delay of streaming flows (served with high priority) without deteriorating other transmissions in the network. It is confirmed by simulation experiments that the implementation of FAN with the ECCM mechanism is a promising solution for the Future Internet. Figure 1. The cross-protect router.ensures fast acceptance of streaming flows in FAN routers, even in congestion, and may be used in each FAN implementation. Moreover, it does not significantly affect the other transmissions in a network and is fully automatic.The cross-protect router (also known as the XP router) is the main element of FAN. Its functionality is presented in Figure 1. The measurement-based admission control (MBAC) accepts or rejects the packets of flows. When congestion is not observed, all packets are accepted, and the identifiers of flows represented by these packets are added to the protected flow list (PFL). In congestion, only packets whose flows are recorded in the PFL are accepted. The scheduler block decides on fair queuing of accepted packets. Moreover, the values of two congestion indicators are periodically estimated in this block. The fair rate (FR) is the rate which is or might be realized (in congestionless state) by a flow, and the priority load (PL) represents the level of priority traffic in the link. If the border values of FR or PL (min_FR or max_PL) in the outgoing link are exceeded, the congestion is noticed.Flow-aware networks have many advantages. Among them, the most important is scalability. It was proved that the number of active flows (which have packets in the queue) to be scheduled does not increase with link capacity and amount of traffic to send. The authors of [5] shown that thanks to the admission control block, this number may be limited to the reasonable number. The second important advantage of FAN is fairness among flows, which is ensured if only links are not saturated (this is ensured by the MBAC). What is also very important, FAN conform to the net neutrality paradigms [6]. In each FAN version, the differentiation of packets is implicit and made by each router in the network independently. In this way, it is possible to differentiate services and maintain fairness and neutrality. Flow-based approaches, like OpenFlow [7] become more and more popular. Flow-aware networking is still an interesting research issue for scientists and researchers all over the world. New solutions for FAN have been recently proposed in [8][9][10][11][12]. The authors of these papers propose new...

Automatic Hidden Bypasses in Software-Defined Networks

“…However, substantial work was necessary to be conducted to serve priority traffic in congestion. There are some mechanisms to solve this problem, like Efficient Congestion Control Mechanism proposed recently in [5]. Such a solution can be more effective when the AHB algorithm is also implemented.…”