Faithful reproduction of network experiments

The proliferation of cloud computing has compelled the research community to rethink fundamental aspects of network systems and architectures. However, the tools commonly used to evaluate new ideas have not kept abreast of the latest developments. Common simulation and emulation frameworks fail to provide scalability, fidelity, reproducibility and execute unmodified code, all at the same time. We present SELENA, a Xen-based network emulation framework that offers fully reproducible experiments via its automation interface and supports the use of unmodified guest operating systems. This allows out-of-the-box compatibility with common applications and OS components, such as network stacks and filesystems. In order to faithfully emulate faster and larger networks, SELENA adopts the technique of time-dilation and transparently slows down the passage of time for guest operating systems. This technique effectively virtualizes the availability of host’s hardware resources and allows the replication of scenarios with increased I/O and computational demands. Users can directly control the tradeoff between fidelity and running-times via intuitive tuning knobs. We evaluate the ability of SELENA to faithfully replicate the behaviour of real systems and compare it against existing popular experimentation platforms. Our results suggest that SELENA can accurately model networks with aggregate link speeds of 44 Gbps or more, while improving by four times the execution time in comparison to ns3 and exhibits near-linear scaling properties.This is the author accepted manuscript. The final version is available from ACM via http://dx.doi.org/10.1145/2658260.265827

Enabling Performance Evaluation beyond 10 Gbps

Despite network monitoring and testing being critical for computer networks, current solutions are both extremely expensive and inflexible. This demo presents OSNT (www.osnt.org), a community-driven, high-performance, open-source traffic generator and capture system built on top of the NetFPGA-10G board which enables flexible network testing. The platform supports full line-rate traffic generation regardless of packet size across the four card ports, packet capture filtering and packet thinning in hardware and sub-msec time precision in traffic generation and capture, corrected using an external GPS device. Furthermore, it provides a software APIs to test the dataplane performance of multi-10G switches, providing a starting point for a number of different test cases. OSNT flexibility is further demonstrated through the OFLOPS-turbo platform: an integration of OSNT with the OFLOPS OpenFlow switch performance evaluation platform, enabling control and data plane evaluation of 10G switches. This demo showcases the applicability of the OSNT platform to evaluate the performance of legacy and OpenFlow-enabled networking devices, and demonstrates it using commercial switches

Reconfigurable network systems and software-defined networking

Modern high-speed networks have evolved from relatively static networks to highly adaptive networks facilitating dynamic reconfiguration. This evolution has influenced all levels of network design and management, introducing increased programmability and configuration flexibility. This influence has extended from the lowest level of physical hardware interfaces to the highest level of network management by software. A key representative of this evolution is the emergence of softwaredefined networking (SDN). In this paper, we review the current state of the art in reconfigurable network systems, covering hardware reconfiguration, SDN, and the interplay between them. We take a top-down approach, starting with a tutorial on software-defined networks. We then continue to discuss programming languages as the linking element between different levels of software and hardware in the network. We review electronic switching systems, highlighting programmability and reconfiguration aspects, and describe the trends in reconfigurable network elements. Finally, we describe the state of the art in the integration of photonic transceiver and switching elements with electronic technologies, and consider the implications for SDN and reconfigurable network systems.This work was jointly supported by the UKs Engineering and Physical Sciences Research Council (EPSRC) Internet Project EP/H040536/1, an EPSRC Research Fellowship grant to Philip Watts (EP/I004157/2), and DARPA and AFRL under contract FA8750-11-C-0249.This is the final version of the article. It first appeared from IEEE via http://dx.doi.org/10.1109/JPROC.2015.243573

Supporting novel home network management interfaces with Openflow and NOX

The Homework project has examined redesign of existing home network infrastructures to better support the needs and requirements of actual home users. Integrating results from several ethnographic studies, we have designed and built a home networking platform providing detailed per-flow measurement and management capabilities supporting several novel management interfaces. This demo specifically shows these new visualization and control interfaces, and describes the broader benefits of taking an integrated view of the networking infrastructure, realised through our router's augmented measurement and control APIs. Aspects of this work have been published: the Homework Database in Internet Management (IM) 2011 and implications of the ethnographic results are to appear at the SIGCOMM W-MUST workshop 2011. Separate, more detailed expositions of the interface elements and system performance and implications are currently under submission at other venues. A partial code release is already available and we anticipate fuller public beta release by Q4 2011

The software defined transport network:fundamentals, findings and futures

The Software Defined Network (SDN) is an established network paradigm, architecture and principles, that attracted significant research effort in recent years. An SDN-enabled infrastructure decouples network control from forwarding and enables direct programming. Recently, there is an increasing effort to introduce SDN support in the transport layers of the network operators WAN infrastructure, like Layer 0 (WDM & DWDM) and Layer 1 (SONET/SDH & OTN) technologies. We refer to this infrastructure as the “Software Defined Transport Network”, and benefits include network management devolvement, timely connectivity provision, improved scalability, and open and flexible programmability using well-defined API. This paper outlines the main elements of Software Defined Transport Networks and highlights relevant Application-Based Network Operations (ABNO) enabling technologies. We demonstrate how this technology will benefit network operators, and provide an overview of research results and deployment examples. Finally, we identify some of the technology gaps and future research opportunities

OFLOPS-Turbo: Testing the next-generation OpenFlow switch

The heterogeneity barrier breakthrough achieved by the OpenFlow protocol is currently paced by the variability in performance semantics among network devices, which reduces the ability of applications to take complete advantage of programmable control. As a result, control applications remain conservative on performance requirements in order to be generalizable and trade performance for explicit state consistency in order to support varying performance behaviours. In this paper we argue that network control must be optimized towards network device capabilities and network managers and application developers must perform informed design decision using accurate switch performance profiles. This becomes highly critical for modern OpenFlow-enabled 10 GbE optical switches which significantly elevate switch performance requirements. We present OFLOPS-Turbo, the integration of the OFLOPS switch evaluation platform, with the OSNT platform, a hardware-accelerated traffic generation and capture system supporting lossless 10 GbE functionality. Using OFLOPS-Turbo, we conduct an evaluation of flow table manipulation capabilities in a representative collection of 10 GbE production OpenFlow switch devices and interpret the evolution of OpenFlow support by comparison with historical data.This work was jointly supported by the EPSRC INTERNET Project EP/H040536/1 and the Defense Advanced Research Projects Agency (DARPA) and the Air Force Research Laboratory (AFRL), under contract FA8750-11- C-0249. The views, opinions, and/or findings contained in this article/presentation are those of the author/ presenter and should not be interpreted as representing the official views or policies, either expressed or implied, of the Defense Advanced Research Projects Agency or the Department of Defense.This is the final version of the article. It first appeared from IEEE via http://dx.doi.org/10.1109/ICC.2015.724921

Network-based telemetry to facilitate the programmable management plane for optical transport infrastructure

Large network operator environments are composed of thousands of nodes and devices capable of performing multiple roles. This network infrastructure is multi-layered, multi-vendor and underpinned by a high capacity and complex optical transport network. Managing this network requires millions of lines of configuration files and hundreds of Operational Support Systems. Typically, the management data structure uses a hierarchical namespace containing tens of thousands of object identifiers (OID). Each OID identifies a variable that can be read, modified or set via management protocol. The British Telecom network collects many millions of OIDs every 10 minutes, and executes many thousands of configuration changes per month via many tools, and multiple generations of protocols, data models and software components. Blending Software Defined Network (SDN) model-driven management and Network Functions Virtualisation (NFV), for on-demand (scale-in and scale-out) virtual network functions (Big Data nodes, network heuristics and analytics), provides an exciting opportunity for significant operational savings: reduced outage impact, simplification of management stack, fault correlation and network healing, and network usage trending for efficient resource allocation and scaling. This paper and talk outlines the management plane challenges and use cases for complex tier-1 optical environments. It discusses how we need to rethink network analytics and embrace streaming telemetry for real-time resource adaptation. It outlines a guiding network telemetry framework being developed by leading operators and the enabling community-driven technologies, and how they may be used to facilitate the programmable management plane for optical transport infrastructure

An open testing framework for next-generation openflow switches

The deployment experience of OpenFlow support in production networks has highlighted variable limitations between network devices and vendors, while the recent integration of OpenFlow control abstractions in 10 GbE switches, increases further the performance requirements to support the switch control plane. This paper presents OFLOPS-Turbo, an effort to integrate OFLOPS, the OpenFlow switch evaluation platform, with OSNT, a hardware-accelerated traffic generation and capture system

Blueswitch: Enabling provably consistent configuration of network switches

Previous research on consistent updates for distributed network configurations has focused on solutions for centralized networkconfiguration controllers. However, such work does not address the complexity of modern switch datapaths. Modern commodity switches expose opaque configuration mechanisms, with minimal guarantees for datapath consistency and with unclear configuration semantics. Furthermore, would-be solutions for distributed consistent updates must take into account the configuration guarantees provided by each individual switch – plus the compositional problems of distributed control and multi-switch configurations that considerably transcend the single-switch problems. In this paper, we focus on the behavior of individual switches, and demonstrate that even simple rule updates result in inconsistent packet switching in multi-table datapaths. We demonstrate that consistent configuration updates require guarantees of strong switch-level atomicity from both hardware and software layers of switches – even in a single switch. In short, the multiple-switch problems cannot be reasonably approached until single-switch consistency can be resolved. We present a hardware design that supports a transactional configuration mechanism, and provides packet-consistent configuration: all packets traversing the datapath will encounter either the old configuration or the new one, and never an inconsistent mix of the two. Unlike previous work, our design does not require modifications to network packets. We precisely specify the hardwaresoftware protocol for switch configuration; this enables us to prove the correctness of the design, and to provide well-specified invariants that the software driver must maintain for correctness. We implement our prototype switch design using the NetFPGA-10G hardware platform, and evaluate our prototype against commercial off-the-shelf switches.This work was jointly supported by the Defense Advanced Research Projects Agency (DARPA) and the Air Force Research Laboratory (AFRL), under contract FA8750-11-C-0249. The views, opinions, and/or findings contained in this article/presentation are those of the author/ presenter and should not be interpreted as representing the official views or policies, either expressed or implied, of the Department of Defense or the U.S. Government. We also acknowledge the support of the UK EPSRC for contributing to parts of our work, through grant EP/H040536/1. Additional data related to this publication is available at the http://www.cl.cam.ac. uk/research/srg/netfpga/blueswitch/ data repository.This is the author accepted manuscript. The final version is available from IEEE via http://dx.doi.org/10.1109/ANCS.2015.711011

Transport Northbound Interface:The need for Specification and Standards coordination

Next generation optical transport networks have high benchmarks for flexibility, reliability, and operational simplicity. These requirements underline a common, technology-independent orchestration paradigm that can be extended to represent and configure specific optical technology attributes. Although, orchestration is an ongoing aspect of the current optical transport network evolution, the meaning and scope of orchestration is often only implied, and various Specification and Standards communities cannot always agree the requirements and objectives. This paper describes the high-level requirements facing optical transport networks to provide well-defined Transport Northbound Interface (T-NBI) for optical resource programmability, control, and management automation. It explores the overall functionality that must be provided, whether encompassed in a single large-scale orchestration wrapper or partitioned into several sub-functions, of which only one component is designated as a transport orchestrator. It highlights the early efforts for optical transport resource modeling across Specification and Standardisation organisations. The paper will report on recent Internet Engineering Task Force (IETF) Transport NBI Team Design Team efforts to collaborate across Standards Development Organisations (SDOs) to unify transport interface requirements and objectives. Finally, the paper will highlight use cases and applicability examples, and outline research gaps and challenges, opportunities for researchers, and areas for further collaboration between academia and industry