An implementation of Min–Max optimization for multipath SCTP through bandwidth estimation based resource pooling technique

The Stream Control Transmission Protocol (SCTP) is a reliable transport protocol to tackle the limitations of TCP and UDP. SCTP was originally designed to transport PSTN signaling messages over IP networks, but is also capable of serving as a general-purpose transport protocol. SCTP provides attractive features such as multi-streaming and multi-homing that may be helpful in high-mobility environment. SCTP congestion control mechanisms are based upon TCP congestion principals with the exception of the fast recovery algorithm. Original SCTP congestion control can perform badly in high-speed wide area networks because of its slow response with large congestion window. We proposed a new congestion control scheme based on the simple congestion window modification for SCTP to improve its performance in high-speed wide area networks. The results of several experiments we performed proved that our new suggested congestion control scheme for SCTP in high-speed network improved the throughput of the original SCTP congestion control scheme significantly.

Recent data centers provide dense inter-connectivity between each pair of servers through multiple paths. These data centers offer high aggregate bandwidth and robustness by using multiple paths simultaneously. Multipath TCP (MPTCP) protocol is developed for improving throughput, fairly sharing network link capacity and providing robustness during path failure by utilizing multiple paths over multi-homed data center networks. Running MPTCP protocol for latency-sensitive rack-local short flows with many-to-one communication pattern at the access layer of multi-homed data center networks creates MPTCP incast problem. In this paper, Balanced Multipath TCP (BMPTCP) protocol is proposed to mitigate MPTCP incast problem in multi-homed data center networks. BMPTCP is a window-based congestion control protocol that prevents constant growth of each worker’s subflow congestion window size. BMPTCP computes identical congestion window size for all concurrent subflows by considering bottleneck Top of Rack (ToR) switch buffer size and increasing count of concurrently transmitting workers. This helps BMPTCP to avoid timeout events due to full window loss at ToR switch. Based on current congestion situation at ToR switches, BMPTCP adjust transmission rates of each worker’s subflow so that total amount of data transmitted by all concurrent subflows does not overflow bottleneck ToR switch buffer. Simulation results show that BMPTCP effectively alleviates MPTCP incast. It improves goodput, reduces flow completion time as compared to existing MPTCP and EW-MPTCP protocols.

We introduce the game-theoretic stochastic routing (GTSR) framework, a proactive alternative to today's reactive approaches to route repair. GTSR minimizes the impact of link and router failure by 1) computing multiple paths between source and destination and 2) selecting among these paths randomly to forward packets. Besides improving fault tolerance, the fact that GTSR makes packets take random paths from source to destination also improves security. In particular, it makes connection eavesdropping attacks maximally difficult as the attacker would have to listen on all possible routes. The approaches developed are suitable for network layer routing, as well as for application layer overlay routing and multipath transport protocols such as the stream control transmission protocol (SCTP). Through simulations, we validate our theoretical results and show how the resulting routing algorithms perform in terms of the security/fault-tolerant/delay/throughput trade-off. We also show that a beneficial side effect of these algorithms is an increase in throughput, as they make use of multiple paths.

One of only two new transport protocols introduced in the last 30 years is the Stream Control Transmission Protocol (SCTP). SCTP enables capabilities like additional throughput and fault tolerance for multihomed hosts. An SCTP implementation is included with the Linux kernel and another implementation called sctplib functions successfully in userspace on several platforms but unfortunately neither of these implementations have all of the latest features nor do they perform as well as the FreeBSD kernel implementation of SCTP. We were motivated to produce a portable implementation of the FreeBSD kernel SCTP stack that operates in userspace of any system because of both our desires to obtain a higher performance SCTP stack for Linux as well as to exploit recent developments in hardware virtualization and transport protocol onloading. Unlike any other userspace transport implementation for TCP or SCTP, our userspace SCTP stack simultaneously achieves similar throughput and latency as the Linux kernel TCP stack, without compromising on any of the transport's features as well as maintaining true portability across multiple operating systems and devices. We create a callback API and implement a threshold to control its usage; our userspace SCTP stack with these optimizations obtains higher throughput than the Linux kernel implementation of SCTP. We describe our userspace SCTP stack's design and demonstrate how it gives similar throughput and latency on Linux as the kernel TCP implementation, with the benefits of the new features of SCTP.

Currently, the new transport protocol, Stream Control Transmission Protocol (SCTP), is not ECN-capable. The ECN-capable SCTP is proposed in this paper, which is bandwidth-efficient and robust to non-congestion losses. A SCTP source needs to adjust its congestion window when receiving ECN messages. We find the optimal value of the congestion window for a SCTP source in response to ECN messages, and develop a simple and practical method to achieve this optimal congestion window. Our simplified method in achieving the optimal congestion window is attractive because the total goodput performance of SCTP associations or the bottleneck link utilization is not sensitive to the window reduction policies when the network load is heavy. Using complicated methods to fine-tune SCTP or TCP's congestion window in response to congestion indications may be not worth the increase in complexity of the protocol.

The stream control transmission protocol (SCTP) is a relatively recent transport protocol, offering features beyond TCP. Although SCTP is an alternative transport protocol for the session initiation protocol (SIP), we do not know how SCTP features influence SIP server scalability and performance. To estimate this, we measured the scalability and performance of two servers, an echo server and a simplified SIP server on Linux, for both SCTP and TCP. Our measurements found that using SCTP does not significantly affect data transfer latency. However, the number of sustainable associations drops to 17-21% or to 50% of the TCP value if we adjust the acceptable gap size of packet reordering.

We characterize the operation of the SCTP transport protocol over the land mobile satellite channel (LMSC), which is subject to intermittent blockages, and contrast its performance with that of TCP. In particular, we study the ability of SCTP's multihoming capability to adjust to channel blockages. For small files, SCTP's larger connection setup overheads cause single-homed connections to complete transfers slightly slower than TCP. However, depending on the ability of alternate paths, multihoming can improve transfer times so much that SCTP is competitive with an optimized TCP gateway. For large files, quirks in the congestion control of multihomed associations cause performance to deteriorate considerably; though single-homed SCTP is faster than end-to-end TCP, none of the other options can compete with a highly optimized satellite TCP gateway operating without congestion control over the satellite channel. SCTP multihoming semantics do not lend themselves to protocol-spoofing gateways, but some changes to default parameters can help. In the LMSC environment, applications would generally do best to use multihomed SCTP (if available) for small file transfers and gateway-enhanced TCP for larger transactions.

With the growing demand of Internet services, network operators have put significant efforts to improve network error resilience and efficiency. Since there exist different wired/wireless technologies for Internet access such as digital subscriber line (DSL), Ethernet, and worldwide interoperability for microwave access (WiMax), a mobile host can use multiple access networks simultaneously with multipath transmission. Taking the advantage of heterogeneous environment, multipath transmission through the Internet can improve service reliability and network flexibility. Ensuring a reliable end-to-end connection oriented communication with satisfactory quality of service (QoS) and maintaining congestion control and flow control are the main responsibilities of the Transmission Control Protocol (TCP), the dominant transport layer protocol in the Internet. In this paper, we survey the state-of-the-art of multipath transmission techniques for QoS provisioning in wireless Internet access, focusing on the end-to-end transport layer protocols. The main challenges for the design of multipath TCP are reviewed, and the existing transport layer congestion control schemes are categorized. Multipath TCP and stream control transmission protocol (SCTP)-based transport layer protocols are discussed, and their limitations and/or impractical assumptions are addressed. Open research issues on the development of an effective, efficient, and practical multipath TCP protocol are summarized.

The Internet’s excellent scalability and robustness result in part from the end-to-end nature of Internet congestion control. End-to-end congestion control algorithms alone however are unable to prevent the congestion collapse and unfairness created by applications that are unresponsive to network congestion. To address these maladies, we propose a modified Queue Management algorithm and Stream Control Transmission Protocol (SCTP) congestion control mechanism. SCTP mechanisms are based upon TCP congestion control principles. It allows network operators to simultaneously achieve high throughput and low average delay. One of the flaws of SCTP is-fast retransmission procedure is vulnerable to being mistakenly triggered multiple times leading to under utilization of the network during recovery and duplicate retransmissions of the lost packet. To solve these problems, we change in determining the congestion window while leaving the basic idea intact and then evaluate its performance using simulation. Simulation results show that our proposed method can effectively eliminates congestion collapse and give better performance than conventional procedure. Based on extensive simulation, we believe that our technique is sufficiently robust for deployment in routers.

Most current web application use HTTP (Hyper Text Transfer Protocol) and TCP (Transmission Control Protocol) to retrieve objects from the Internet. SCTP (Stream Control Transmission Protocol) is recently proposed transport protocol with congestion control mechanism similar to that of TCP. Waiting delay is an important performance criterion for when transferring web object over the Internet. In this paper, we present an analytical model of mean waiting delay for object transfers over the Internet in a wireless using the SCTP as the transport protocol and compare with the mean waiting in using TCP. Validation of the model using experimental results show that the mean waiting delay for HTTP over SCTP is less than that for HTTP over TCP. This is caused by the small slow-start time of SCTP.

The stream control transmission protocol (SCTP) is a transport protocol that is robust against network failure. However, it cannot select routes for packet rerouting unless the receiver is a multi-homed host. We propose a method that allows single-homed hosts to support SCTP multi-path access; it allows hosts in a local network to select routes to single-homed severs on the Internet. In this method, a single-homed client constitutes a virtual multi-homed client with a Multi-path gateway (MPGW) and communicates with a single-homed server over multiple routes. Our experiments show that a virtual multi-homed client can communicate with a normal SCTP server and that the method establishes connections that experience the same network failure to recover at different times, whereas IP dynamic routing recovers them at the same time.

The Stream Control Transmission Protocol (SCTP) is a relatively new transport protocol. It has several underlying mechanisms that are similar to the Transmission Control Protocol (TCP), as well as several improvements that are important in certain classes of applications. The timeout scheme of SCTP, however, is almost identical to that used in TCP. With dynamics of today's Internet, that timeout scheme may be too passive. This paper presents an algorithm which dynamically adjusts the overall context of the retransmission timeout process without changing the fundamental retransmission mechanisms. This approach manages the impact of fast retransmissions and timeouts to significantly improve the throughput of SCTP applications. The algorithm avoids spurious retransmissions and provides better throughput by intelligently managing RTO boundaries and allowing conventional timeout schemes to participate more actively in the retransmission process.

Stream Control Transmission Protocol (SCTP) is an emerging transport protocol for sending data from one point to another over the Internet. The two major new capabilities that are designed into SCTP are the support for multi-homed hosts and the support for multiple streams in a single SCTP association. The purpose of this paper is to investigate the performance of SCTP, measured in terms of association throughput. We analyze the throughput for two experimental scenarios: 1. Transmission of data chunks with different sizes of payload in network stable state (no packet loss). 2. Transmission of data chunks with different sizes of payload in packet loss environment. We have shown the impact of data chunk transmissions with different sizes of payload on the throughput of a multi-homed SCTP association. Our experimental results and analysis show that SCTP provides better throughput in the case of large payload data chunks transmission in both network stable state and packet loss environment.

Space-ground integrated networks (SGINs) have been recently regarded as a promising way to provide resilient, dependable as well as efficient data transmission in the high-speed railway (HSR) scenario. Applying multipath transmission control protocol (MPTCP) to SGIN can realize data transmission simultaneously via terrestrial and satellite networks. However, since the existing congestion control (CC) mechanisms of MPTCP fail to distinguish between adverse influences (such as packet loss and/or round-trip time increase) caused by congestion and those caused by handovers, it suffers severe performance degradation in the HSR scenario where handover frequently occurs. In this article, we first present the SGIN oriented HSR (SGIN-HSR) with MPTCP. Then leveraging cross-layer information (i.e., reference signal received power), we design a novel cross-layer aided MPTCP CC mechanism targeted at SGIN-HSR based on deep reinforcement learning, which is referred to as HSR-CC, to alleviate performance degradation problems induced by handover. The experimental results show that HSR-CC significantly enhances the goodput and outperforms state-of-the-art MPTCP CC algorithms in SGIN-HSR environments where handover frequently occurs.

The Internet-wide deployment of new transport protocols such as the Stream Control Transmission Protocol (SCTP) is a difficult matter. While SCTP could be beneficial in many cases, it is still a major challenge to enable applications to use the new protocol. We believe that its deployment could be significantly accelerated by introducing an intermediate step: transparent usage below TCP, such that TCP-based applications automatically obtain a benefit. We have implemented a Linux based TCP-SCTP mapping tool that exploits SCTP's multi-streaming feature, and carried out measurements which show that such an approach can significantly improve the performance of TCP applications. However, and perhaps more importantly, we also encountered difficulties, which lead us to make some concrete recommendations regarding future research and the implementation and specification of SCTP itself.