Junaid Khalid

OpenNF: enabling innovation in network function control

Network functions virtualization (NFV) together with software-defined networking (SDN) has the potential to help operators satisfy tight service level agreements, accurately monitor and manipulate network traffic, and minimize operating expenses. However, in scenarios that require packet processing to be redistributed across a collection of network function (NF) instances, simultaneously achieving all three goals requires a framework that provides efficient, coordinated control of both internal NF state and network forwarding state. To this end, we design a control plane called OpenNF. We use carefully designed APIs and a clever combination of events and forwarding updates to address race conditions, bound overhead, and accommodate a variety of NFs. Our evaluation shows that OpenNF offers efficient state control without compromising flexibility, and requires modest additions to NFs.

Measuring control plane latency in SDN-enabled switches

Timely interaction between an SDN controller and switches is crucial to many SDN applications---e.g., fast rerouting during link failure and fine-grained traffic engineering in data centers. However, it is not well understood how the control plane in SDN switches impacts these applications. To this end, we conduct a comprehensive measurement study using four types of production SDN switches. Our measurements show that control actions, such as rule installation, have surprisingly high latency, due to both software implementation inefficiencies and fundamental traits of switch hardware.

Design and implementation of a framework for software-defined middlebox networking

Middleboxes (MBs) are used widely to ensure security (e.g., intrusion detection systems), improve performance (e.g., WAN optimizers), and provide other novel network functionality [4, 6]. Recently, researchers have proposed several new architectures for MB deployment, including Stratos [2], CoMb [4], and APLOMB [6]. These frameworks all advocate dynamic deployment of software-based MBs with the goal of increasing flexibility, improving efficiency, and reducing management overhead. However, approaches for controlling the behavior of MBs (i.e., how MBs examine and modify network traffic) remain limited. Today, configuration policies and parameters are manipulated using narrow, MB-specific configuration interfaces, while internal algorithms and state are completely inaccessible and unmodifiable. This apparent lack of finegrained control over MBs and their state precludes correct and performant implementation of control scenarios that involve re-allocating live flows across MBs: e.g., server migration, scale up/down of MBs to meet cost-performance trade-offs, recovery from network or MB failures, etc. Several key requirements must be satisfied to effectively support the above scenarios. To illustrate these requirements, we consider a scenario where MB instances are added and removed based on current network load [2] (Figure 1). When scaling up, some in-progress flows may need to be moved to a new MB instance to reduce the load on the original instance. To preserve the correctness and fidelity of MB operations, the new instance must receive the internal MB state associated with the moved flows, while the old instance still has the internal state associated with the remaining flows. For some MBs (e.g., an intrusion prevention

Energy and distortion analysis of video compression schemes for Wireless Video Sensor Networks

Wireless Video Sensor Networks (WVSNs) - a type of WSNs - comprise of sensor nodes that can capture, process and communicate video frames. The battery powered sensor nodes have limited hardware resources while video processing and communication are resource intensive tasks i.e., require high-end processors, large memory and bandwidth. Video encoding is a popular method used to reduce the communication overhead but being an inherently complex process it results in higher computational energy-drain on video sensor nodes. This establishes an interesting computation-communication tradeoff for energy efficient video communication (encoding and transmission) in WVSNs. In this paper, we study this computation-communication tradeoff under Intel-imote2 based single-hop and multi-hop video sensor networks testbed by empirically evaluating selected implementations of the MPEG-4 (Part 2) and H.264/AVC encoders. The analysis has been carried out to characterize the performance of encoders in terms of energy efficiency, compression efficiency and video distortion. The experimental results show that in single-hop WVSNs, MPEG-4 is energy efficient over H.264 whilst in multi-hop WVSNs, H.264 is energy efficient over MPEG-4.

Latency in Software Defined Networks: Measurements and Mitigation Techniques

We conduct a comprehensive measurement study of switch control plane latencies using four types of production SDN switches. Our measurements show that control actions, such as rule installation, have surprisingly high latency, due to both software implementation inefficiencies and fundamental traits of switch hardware. We also propose three measurement-driven latency mitigation techniques---optimizing route selection, spreading rules across switches, and reordering rule installations---to effectively tame the flow setup latencies in SDN.

Harmony: coordinating network, compute, and storage in software-defined clouds

The progress of a big data job is often a function of storage, networking and processing. Hence, for efficient job execution, it is important to collectively optimize all three components. Prior proposals [1], in contrast, have focused on mainly on one or two of the three components. This narrow focus constraints the extent to which these proposals can support efficient operation of big data applications.

A Standardized Southbound API for VNF Management

Network Function Virtualization (NFV) offers network operators great flexibility toward managing network functions, i.e. in-network appliances such as firewalls, load balancers and NATs. Several frameworks exist to this end; however VNF management is fragmented, and no standard management API exists. As a result, each framework uses a proprietary API which a network function must support to fully realize its benefits. This lack of standardization is a major barrier in the wider adoption of NFV. We propose a standard, framework-agnostic southbound API to facilitate faster adoption of NFV and enable innovation in the design of both management frameworks and network functions.

Bit Error Rate Comparison of OFDM and MC-CDMA Systems

In this paper we use multi-carrier code division multiple access (MC-CDMA) with recursive least square (RLS) equalizer used for channel estimation and equalization then compare it with orthogonal frequency division multiplexing (OFDM). RLS algorithm is used because its converges faster leading to faster and better results compared to other algorithms. Results are received by simulating the transmission of the signals over Rayleigh fading additive white Gaussian noise (AWGN) channel. Objective is to prove that the bit error rate of MC-CDMA system falls more rapidly as we increase the transmitted signal power compared to the OFDM system.