HARMLESS: Cost-Effective Transitioning to SDN

Recently, Software-Defined Networking has grown out of being an "intriguing approach" and turned into a "must-have" for communication networks to overcome many long-standing problems of traditional networking. However, there are still some obstacles on the way to the widespread adoption. Current commodity-off-the-shelf (COTS) SDN offerings are still in their infancy and are notorious for lacking standards compliance, scalability, and unpredictable performance indicators compared to their legacy counterparts. On the other hand, recent software-based solutions might mitigate these shortcomings, but in terms of cost-efficiency and port density they are in a lower league. Here, we present HARMLESS, a novel SDN switch design that combines the rapid innovation and upgrade cycles of software switches with the port density of hardware-based appliances into a fully data plane-transparent, vendor-neutral and cost-effective solution for smaller enterprises to gain a foothold in this era. The demo showcases the SDN migration of a dumb legacy Ethernet switch to a powerful, fully reconfigurable, OpenFlow-enabled network device without incurring any major performance and latency penalty, nor any substantial price tag enabling to realize many use cases that would have otherwise needed standalone hardware appliances

ATP: a Datacenter Approximate Transmission Protocol

Many datacenter applications such as machine learning and streaming systems do not need the complete set of data to perform their computation. Current approximate applications in datacenters run on a reliable network layer like TCP. To improve performance, they either let sender select a subset of data and transmit them to the receiver or transmit all the data and let receiver drop some of them. These approaches are network oblivious and unnecessarily transmit more data, affecting both application runtime and network bandwidth usage. On the other hand, running approximate application on a lossy network with UDP cannot guarantee the accuracy of application computation. We propose to run approximate applications on a lossy network and to allow packet loss in a controlled manner. Specifically, we designed a new network protocol called Approximate Transmission Protocol, or ATP, for datacenter approximate applications. ATP opportunistically exploits available network bandwidth as much as possible, while performing a loss-based rate control algorithm to avoid bandwidth waste and re-transmission. It also ensures bandwidth fair sharing across flows and improves accurate applications' performance by leaving more switch buffer space to accurate flows. We evaluated ATP with both simulation and real implementation using two macro-benchmarks and two real applications, Apache Kafka and Flink. Our evaluation results show that ATP reduces application runtime by 13.9% to 74.6% compared to a TCP-based solution that drops packets at sender, and it improves accuracy by up to 94.0% compared to UDP

Feasibility Analysis of the Algorithms: Secured and Efficient Routing Path Update in Software Defined Networking (SDN)

Software-defined networking is the talk of the town in today’s networking industry. Because of the limitations of traditional networking, SDN is getting more popular every year. Lots of researches are taking place to improve the efficiency and overcome the challenges of SDN though it has many advantages. Hence one key problem of SDN is the network update. If the route update does not perform well, it causes congestion and inconsistencies in the network system whereas bandwidth utilization and security is our main concern. We have compared two pre-built algorithms especially for routing path update and proposed a new algorithm with maximum security and loop-free network

Joint Probabilistic-Nyquist Pulse Shaping for an LDPC-Coded 8-PAM Signal in DWDM Data Center Communications

M-ary pulse-amplitude modulation (PAM) meets the requirements of data center communication because of its simplicity, but coarse entropy granularity cannot meet the dynamic bandwidth demands, and there is a large capacity gap between uniform formats and the Shannon limit. The dense wavelength division multiplexing (DWDM) system is widely used to increase the channel capacity, but low spectral efficiency of the intensity modulation/direct detection (IM/DD) solution restricts the throughput of the modern DWDM data center networks. Probabilistic shaping distribution is a good candidate to offer us a fine entropy granularity and efficiently reduce the gap to the Shannon limit, and Nyquist pulse shaping is widely used to increase the spectral efficiency. We aim toward the joint usage of probabilistic shaping and Nyquist pulse shaping with low-density parity-check (LDPC) coding to improve the bit error rate (BER) performance of 8-PAM signal transmission. We optimized the code rate of the LDPC code and compared different Nyquist pulse shaping parameters using simulations and experiments. We achieved a 0.43 dB gain using Nyquist pulse shaping, and a 1.1 dB gain using probabilistic shaping, while the joint use of probabilistic shaping and Nyquist pulse shaping achieved a 1.27 dB gain, which offers an excellent improvement without upgrading the transceivers.Open access journalThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

Faster enclave transitions for IO-intensive network applications

Process-based confidential computing enclaves such as Intel SGX have been proposed for protecting the confidentiality and integrity of network applications, without the overhead of virtualization. However, these solutions introduce other types of overhead, particularly the cost transitioning in and out of an enclave context. This makes the use of enclaves impractical for running IO-intensive applications, such as network packet processing. We build on ear- lier approaches to improve the IO performance of workloads in Intel SGX enclaves and propose the HotCall-Bundler library that helps reduce the cost of individual single enclave transitions and the total number of enclave transitions in trusted applications running in Intel SGX enclaves. We describe the implementation of the HotCall-Bundler library, evaluate its performance and demonstrate its practicality using the case study of Open vSwitch, a widely used software switch implementation

QoE-Based Low-Delay Live Streaming Using Throughput Predictions

Recently, HTTP-based adaptive streaming has become the de facto standard for video streaming over the Internet. It allows clients to dynamically adapt media characteristics to network conditions in order to ensure a high quality of experience, that is, minimize playback interruptions, while maximizing video quality at a reasonable level of quality changes. In the case of live streaming, this task becomes particularly challenging due to the latency constraints. The challenge further increases if a client uses a wireless network, where the throughput is subject to considerable fluctuations. Consequently, live streams often exhibit latencies of up to 30 seconds. In the present work, we introduce an adaptation algorithm for HTTP-based live streaming called LOLYPOP (Low-Latency Prediction-Based Adaptation) that is designed to operate with a transport latency of few seconds. To reach this goal, LOLYPOP leverages TCP throughput predictions on multiple time scales, from 1 to 10 seconds, along with an estimate of the prediction error distribution. In addition to satisfying the latency constraint, the algorithm heuristically maximizes the quality of experience by maximizing the average video quality as a function of the number of skipped segments and quality transitions. In order to select an efficient prediction method, we studied the performance of several time series prediction methods in IEEE 802.11 wireless access networks. We evaluated LOLYPOP under a large set of experimental conditions limiting the transport latency to 3 seconds, against a state-of-the-art adaptation algorithm from the literature, called FESTIVE. We observed that the average video quality is by up to a factor of 3 higher than with FESTIVE. We also observed that LOLYPOP is able to reach a broader region in the quality of experience space, and thus it is better adjustable to the user profile or service provider requirements.Comment: Technical Report TKN-16-001, Telecommunication Networks Group, Technische Universitaet Berlin. This TR updated TR TKN-15-00

Decentralized monitoring for large-scale Software-Defined Networks

The Software-Defined Networking (SDN) paradigm can allow network management solutions to automatically and frequently reconfigure network resources. When developing SDN-based management architectures, it is of paramount importance to design a monitoring system that can provide frequent and consistent updates to heterogeneous management applications. For the monitoring functionality to scale according to the requirements of large-scale networks a distributed monitoring approach is required. In this paper we present a decentralized approach for resource monitoring in SDN, which is designed to support a wide range of measurement tasks and requirements in terms of monitoring rates and information granularity levels. Our solution leverages effective processing of the monitoring requests to reduce the consumption of limited resources, such as the control plane bandwidth of OpenFlow switches. To demonstrate the benefits of the proposed approach, our evaluation is based on a realistic and demanding use case, where a distributed management application coordinates a content distribution service in an ISP network