TCP exhibits inherent unfairness towards connections with long round-trip times and connections that have to traverse multiple congested routers. We have previously proposed a TCP Bandwidth Allocation (TBA) algorithm to solve this problem and proved its effectiveness in wireline networks. In this paper, we apply the TBA algorithm to improve TCP fairness over heterogeneous wireless networks with...

We present a new approach for seamless congestion control over heterogeneous networks containing wired and wireless IEEE 802.11 links. The approach uses ECN (Explicit Congestion Notification) as a common signalling mechanism for conveying congestion information from both wired and wireless links. Two additional novel aspects of the approach are that ECN marking for a wireless link, due to the w...

The next generation wireless networks are posited to support large scale data applications. Implementing end-to-end TCP in such networks faces two problems. First, it is well known that TCP can not distinguish packet losses due to link failures and that due to network congestion. Second, TCP congestion control mechanism does not deal effectively with large amount of out-oforder packet retransmi...

Quality of service (QoS) generally represents the performance of packet networks. Quality of experience (QoE) defines the quality perceived by end-users of applications running on these networks. This paper relates these two metrics in a novel way using the newly defined congestion exposure (ConEx) mechanism. ConEx is an experimental protocol defined by the IETF that allows the sender of a flow...

This note describes a proposed addition of ECN (Explicit Congestion Notification) to IP. TCP is currently the dominant transport protocol used in the Internet. We begin by describing TCP’s use of packet drops as an indication of congestion. Next we argue that with the addition of active queue management (e.g., RED) to the Internet infrastructure, where routers detect congestion before the queue...

Explicit Congestion Notification (ECN) for IP networks has received considerable attention in recent years, and has been shown to improve TCP goodput. Previous studies have centered on scenarios in which TCP with ECN (TCP/ECN) traffic competes with ECN-unaware traffic. This paper presents case studies in which moderately short flows are all ECN-capable, and compare them with the corresponding c...

This memo presents a performance study of the Explicit Congestion Notification (ECN) mechanism in the TCP/IP protocol using our implementation on the Linux Operating System. ECN is an end-to-end congestion avoidance mechanism proposed by [6] and incorporated into RFC 2481[7]. We study the behavior of ECN for both bulk and transactional transfers. Our experiments show that there is improvement i...

Explicit Congestion Notification (ECN) is a TCP/IP extension that can avoid packet loss and thus improve network performance. Though standardized in 2001, it is barely used in today’s Internet. This study, following on previous active measurement studies over the past decade, shows marked and continued increase in the deployment of ECNcapable servers, and usability of ECN on the majority of pat...

Vehicular Ad-Hoc Networks (VANETs), a special kind of Mobile Ad-Hoc Networks (MANETs), where wirelessequipped (road) vehicles form a network without any additional infrastructure. Due to the fast growing number of vehicles and saturation of the transportation infrastructure traffic congestion, accidents and transportation delays become unavoidable. Several measures are implemented in order to s...

The objective of Pre-Congestion Notification (PCN) is to protect the quality of service (QoS) of inelastic flows within a Diffserv domain. On every link in the PCN-domain, the overall rate of PCN-traffic is metered, and PCN-packets are appropriately marked when certain configured rates are exceeded. Egress nodes provide decision points with information about the PCN-marks of PCN-packets that al...