SDN-BASED MECHANISMS FOR PROVISIONING QUALITY OF SERVICE TO SELECTED NETWORK FLOWS

Despite the huge success and adoption of computer networks in the recent decades, traditional network architecture falls short of some requirements by many applications. One particular shortcoming is the lack of convenient methods for providing quality of service (QoS) guarantee to various network applications. In this dissertation, we explore new Software-Defined Networking (SDN) mechanisms to provision QoS to targeted network flows. Our study contributes to providing QoS support to applications in three aspects. First, we explore using alternative routing paths for selected flows that have QoS requirements. Instead of using the default shortest path used by the current network routing protocols, we investigate using the SDN controller to install forwarding rules in switches that can achieve higher bandwidth. Second, we develop new mechanisms for guaranteeing the latency requirement by those applications depending on timely delivery of sensor data and control signals. The new mechanism pre-allocates higher priority queues in routers/switches and reserves these queues for control/sensor traffic. Third, we explore how to make the applications take advantage of the opportunity provided by SDN. In particular, we study new transmission mechanisms for big data transfer in the cloud computing environment. Instead of using a single TCP path to transfer data, we investigate how to let the application set up multiple TCP paths for the same application to achieve higher throughput. We evaluate these new mechanisms with experiments and compare them with existing approaches

Load-Balancing in Local and Metro-Area networks with MPTCP and OpenFlow

In this thesis, a novel load-balancing technique for local or metro-area traffic is proposed in mesh-style topologies. The technique uses Software Defined Networking (SDN) architecture with virtual local area network (VLAN) setups typically seen in a campus or small-to-medium enterprise environment. This was done to provide a possible solution or at least a platform to expand on for the load-balancing dilemma that network administrators face today. The transport layer protocol Multi-Path TCP (MPTCP) coupled with IP aliasing is also used. The trait of MPTCP of forming multiple subflows from sender to receiver depending on the availability of IP addresses at either the sender or receiver helps to divert traffic in the subflows across all available paths. The combination of MPTCP subflows with IP aliasing enables spreading out of the traffic load across greater number of links in the network, and thereby achieving load balancing and better network utilization. The traffic formed of each subflow would be forwarded across the network based on Hamiltonian \u27paths\u27 which are created in association with each switch in the topology which are directly connected to hosts. The amount of \u27paths\u27 in the topology would also depend on the number of VLANs setup for the hosts in the topology. This segregation would allow for network administrators to monitor network utilization across VLANs and give the ability to balance load across VLANs. We have devised several experiments in Mininet, and the experimentation showed promising results with significantly better throughput and network utilization compared to cases where normal TCP was used to send traffic from source to destination. Our study clearly shows the advantages of using MPTCP for load balancing purposes in SDN type architectures and provides a platform for future research on using VLANs, SDN, and MPTCP for network traffic management

Exploiting the power of multiplicity: a holistic survey of network-layer multipath

The Internet is inherently a multipath network: For an underlying network with only a single path, connecting various nodes would have been debilitatingly fragile. Unfortunately, traditional Internet technologies have been designed around the restrictive assumption of a single working path between a source and a destination. The lack of native multipath support constrains network performance even as the underlying network is richly connected and has redundant multiple paths. Computer networks can exploit the power of multiplicity, through which a diverse collection of paths is resource pooled as a single resource, to unlock the inherent redundancy of the Internet. This opens up a new vista of opportunities, promising increased throughput (through concurrent usage of multiple paths) and increased reliability and fault tolerance (through the use of multiple paths in backup/redundant arrangements). There are many emerging trends in networking that signify that the Internet's future will be multipath, including the use of multipath technology in data center computing; the ready availability of multiple heterogeneous radio interfaces in wireless (such as Wi-Fi and cellular) in wireless devices; ubiquity of mobile devices that are multihomed with heterogeneous access networks; and the development and standardization of multipath transport protocols such as multipath TCP. The aim of this paper is to provide a comprehensive survey of the literature on network-layer multipath solutions. We will present a detailed investigation of two important design issues, namely, the control plane problem of how to compute and select the routes and the data plane problem of how to split the flow on the computed paths. The main contribution of this paper is a systematic articulation of the main design issues in network-layer multipath routing along with a broad-ranging survey of the vast literature on network-layer multipathing. We also highlight open issues and identify directions for future work

SEMPER: a stateless traffic engineering solution for WAN based on MP-TCP

Proceeding of: IEEE International Conference on Communications (ICC 2018)Enterprise Networking has a strong set of requirements in terms of resiliency, reliability and resources usage. With current approaches being based on monolithic and expensive infrastructures using dedicated overlay links, providers are moving to more economical hybrid solutions that encompass private dedicated links with public/regular Internet connections. However, these usually rely on complex, hardware-dependent and/or proprietary Traffic Engineering (TE) solutions, which are computationally costly, in particular for the forwarding nodes. In this paper, we propose SEMPER: a lightweight TE solution based on MP-TCP that, in contrast to other TE solutions, moves the complexity to the endpoints of the connection, and relieves the forwarding elements from complex operations or even maintaining state. As our evaluation shows, SEMPER efficiently makes use of all available paths between the endpoints while maintaining fairness, and properly adapts to variations on the available capacity.This work has been partly supported by the H2020 5GMoNArch project (grant agreement 761445), and by the Madrid Regional Government through the TIGRE5-CM program (S2013/ICE-2919)

Datacenter Traffic Control: Understanding Techniques and Trade-offs

Datacenters provide cost-effective and flexible access to scalable compute and storage resources necessary for today's cloud computing needs. A typical datacenter is made up of thousands of servers connected with a large network and usually managed by one operator. To provide quality access to the variety of applications and services hosted on datacenters and maximize performance, it deems necessary to use datacenter networks effectively and efficiently. Datacenter traffic is often a mix of several classes with different priorities and requirements. This includes user-generated interactive traffic, traffic with deadlines, and long-running traffic. To this end, custom transport protocols and traffic management techniques have been developed to improve datacenter network performance. In this tutorial paper, we review the general architecture of datacenter networks, various topologies proposed for them, their traffic properties, general traffic control challenges in datacenters and general traffic control objectives. The purpose of this paper is to bring out the important characteristics of traffic control in datacenters and not to survey all existing solutions (as it is virtually impossible due to massive body of existing research). We hope to provide readers with a wide range of options and factors while considering a variety of traffic control mechanisms. We discuss various characteristics of datacenter traffic control including management schemes, transmission control, traffic shaping, prioritization, load balancing, multipathing, and traffic scheduling. Next, we point to several open challenges as well as new and interesting networking paradigms. At the end of this paper, we briefly review inter-datacenter networks that connect geographically dispersed datacenters which have been receiving increasing attention recently and pose interesting and novel research problems.Comment: Accepted for Publication in IEEE Communications Surveys and Tutorial

Disk-to-Disk Data Transfer using A Software Defined Networking Solution

There have been efforts towards improving the network performance using software defined net-working solutions. One such work is Steroid OpenFlow Service (SOS), which utilizes multiple parallel TCP connections to enhance the network performance transparently to the user. SOS has shown significant improvements in the memory-to-memory data transfer throughput; however, it’s perfor-mance for disk-to-disk data transfer hasn’t been studied. For computing applications involving big data, the data files are stored on non-volatile storage devices separate from the computing servers. Before computing can occur, large volumes of data must be fetched from the “remote” storage devices to the computing server’s local storage device. Since hard drives are the most commonly adopted storage devices today, the process is often called “disk-to-disk” data transfer. For production high performance computing facilities, specialized high throughput data transfer software will be provided for users to copy the data first to a data transfer node before copying to the computing server. Disk-to-Disk data transfer’s throughput performance depends on the network throughput be-tween servers and disk access performance between each server and its storage device. Due to large data sizes the storage devices are typically parallel file systems spanning multiple disks. Disk oper-ations in the disk-to-disk data transfer includes disk read and write operations. The read operation in the transfer is to read the data from the disks and store it in memory. The second step in the transfer is to send out the data to the network through the network interface. Data reaching the destination server is then stored to the disk. Data transfer is faced by multiple delays and is limited at each step of the transfer. To date, one commonly adopted data transfer solution is GridFTP developed by the Argonne National Laboratory. It requires custom application installations and configurations on the hosts. SOS, on the other hand, is a transparent network application without special user software. In this thesis, disk-to-disk data transfer performance is studied with both GridFTP and SOS. The thesis focuses on to two topics, one is the detailed analysis of transfer components for each tool and the second part consists of a systematic experiment to study the two. The experimentation and analysis of the results shows that configuring the data nodes and network with correct parameters results in maximum performance for disk-to-disk data transfer. The GridFTP, for example, is able to get to close to 7Gbps by using four parallel connections with TCP buffer size of 16MB. It achieves the maximum performance by filling the network pipe which has 10Gbps end-to-end link with round trip time (RTT) of 53ms