Scalable IP-VPN flow control mechanism supporting arbitrary fairness criteria - part 1: architecture design

Abstract

In recent years, IP-based virtual private networks (IP-VPNs), which provide a virtual privately owned network over an IP network, have attracted attention. With existing IP-VPNs, however, there is a serious problem that fairness among IP-VPN customers is not satisfied. In this paper, we first discuss design objectives of a control mechanism for achieving fair IP-VPN services: achieving inter-VPN fairness, achieving intra-VPN fairness, easy deployment into existing IP networks, and achieving a high scalability. We then propose an IP-VPN fairness control called I2FVC (Inter-and Intra-VPN Fairness Control) for realizing a fair IP-VPN service in a scalable way. The core of I2VFC is an AIMD (Additive Increase and Multiplicative Decrease) window flow control operating among IP-VPN service provider's edge routers. I2VFC has the advantage that an IP-VPN service provider can arbitrarly specify inter-VPN fairness criteria by utilizing analytic results of AIMD window flow control. Moreover, I2VFC can be easily deployed into existing IP networks by simply modifying edge routers. Through several simulation experiments, we demonstrate that I2VFC realizes both inter-VPN fairness and intra-VPN fairness with extremely high accuracy.

Scalable IP-VPN Flow Control Mechanism Supporting Arbitrary Fairness Criteria - Part 2: Simulation and Implementation

“…This paper quantitatively evaluates the effectiveness of I2VFC proposed in our previous work [4] through simulation experiments and prototype system experiments. The results demonstrated that (1) inter-VPN fairness can be achieved with an extremely high accuracy regardless of settings of I2VFC control parameters, (2) arbitrary fairness including the MaxMin fairness can be achieved even in a network with multiple bottleneck links, (3) congestion of the bottleneck link is dispersed, and consequently fairness among TCP connections (intra-VPN fairness) is improved, and (4) our I2VFC has a practically sufficient scalability in terms of the transfer rate and the number of VPNs accommodated.…”

“…TCP's congestion avoidance phase operating on end hosts corresponds to AIMD window flow control with a = 1.0 and b = 0.5. Hence, it is expected that I2VFC's window flow control operates satisfactorily with parameter settings of a < 1.0 and b < 0.5 [4].…”

“…Namely, I2VFC itself does not perform any control for achieving intra-VPN fairness. The congestion control mechanism of TCP achieves sufficient intra-VPN fairness because flows accommodated in the same VPN have the same round-trip time and the same packet loss rate [4].…”

“…The multiplicative decrease factor for VPN flow 1 is set to b = 0.01. Values of the multiplicative decrease factor b for other VPN flows are configured according to the measured packet loss rate and round-trip time [4]. Evolution of the fairness index for inter-VPN fairness is plotted in Fig.…”

“…This is because the IP network is a best-effort network, so the IP-VPN constructed on it is also a best-effort network. In our previous work [4], we have proposed I2VFC (Inter-and Intra-VPN Fairness Control) to achieve fair IP-VPN services within a layer 3 provider-provisioned VPN (L3-PPVPN) framework [5].…”