Knowledge Base

Title Authors Category Updated
Radio Frequency Interference and Capacity Reduction in DSL Padmabala Venugopal (UNH-IOL), Michael J. Carter, Scott A. Valcourt

The issue of radio frequency interference in Digital Subscriber Line (DSL) networks is of particular concern in urban areas with many strong radio sources nearby. This paper investigates in detail the mechanisms underlying the capacity reduction due to the presence of radio frequency signals from Amplitude Modulated (AM) broadcast stations in an ADSL network. An ADSL system, channel, and radio frequency interference noise were simulated in MATLAB. The capacity reduction due to different Radio Frequency (RF) ingress conditions was studied. Spectral Spreading of the RF interferer, as suggested by Harris et al [1], is a primary cause of capacity reduction, but only at long loop lengths where the signal to Gaussian noise ratio is very low.

White Papers November 4, 2002
Quartz Crystal Resonators and Oscillators for Frequency Control and Timing Applications - A Tutorial John Vig

This is a slide deck.
Chapter 1 (20 slides) provides an overview of clock synchronization applications.
Chapter 7 (11 slides) compares various types of oscillator.
Chapter 8 (33 slides) provides an overview of timekeeping.
The remainder of the 300 slides describe engineering details of quartz oscillators.

External Links October 22, 2014
Quality of Service Testing Methodology Ankur Chadda

Typically, a network service provider offers best-effort service to customers and Quality of Service (QoS) is provided only by network over provisioning. When traffic bursts cause congestion, this default approach does not always provide an acceptable solution. As the trend in networking is convergence of voice, video and data, it is important to differentiate traffic into high and low priority classes through QoS mechanisms. To deliver differentiated QoS, the routers utilize classification and sometimes remarking of the traffic. Based on service agreements with the customer, a certain class of traffic is then given more resources by the router. Evaluation of the results of these methods and approaches on the network performance is very important to device designers, network evaluators, network administrators, network operators and others involved. To study the effects of QoS solutions/techniques on the traffic, methods for testing need to be developed. The objective of this thesis is to propose methods of measuring QoS metrics like throughput, latency, and jitter for different types of traffic through a device. Classification and remarking were observed to put extra load on a device. For some devices, the performance deteriorates when classification and remarking are enabled. Throughput was seen to drop for classification and remarking in some cases. In multiple instances, latency and jitter increased for classification and remarking. There are multiple ways of measuring jitter which were also discussed in the methodology development. It was also observed that some definitions which might seem better from a research perspective are not always available to measure or widely used in the industry. Based on the study it was concluded that service/network providers will have to take care while providing QoS to the customers in order avoid the scenarios discussed here.

Theses December 13, 2004
QOS Over ADSL Praveen Reguraman

Today's digital economy, dominated and driven by the growing commercial outlook of the Internet, has stimulated the demand for broadband networking as well as Quality of Service (QoS) architectures to achieve application performance and user satisfaction. Asymmetric Digital Subscriber Line (ADSL) is gaining prominence as a cost-effective broadband access solution for high speed Internet access, being widely deployed nationwide. The promise and potential to handle applications like Video on Demand over ADSL has set the stage to engineer and evaluate QoS in ADSL systems. As a first step in this direction, the various issues applicable to QoS over ADSL are discussed and a test setup was developed to evaluate the QoS metrics with respect to the physical layer characteristics of ADSL systems. The results of the preliminary set of experiments and the insight gained from these will be presented along with recommendations for future work.

Theses December 7, 2000
PTP Background and Overview Jeff Laird

Terms used when discussing PTP

White Papers June 28, 2012
Proceedings of the 5th Annual Linux Showcase & Conference Ashish Palekar, Narendran Ganapathy, Anshul Chadda, Robert D. Russell

Design And Implementation Of A Linux SCSI Target For Storage Area Networks.

White Papers June 29, 2012
Presentation on the 10GEC Bob Noseworthy

Presented at the 10Gigabit Ethernet User Conference, Nov 1 2002

Tutorials November 5, 2002
PPP Design, Implementation, and Debugging, Second Edition James Carlson

From the back cover: "PPP Design, Implementation, and Debugging, Second Edition, is a complete and convenient resrouce for netowrk system designers and administrators. This book contains everything you need to know to work with the Point-to-Point Protocol (PPP), one of the most important Internet protocols in use today. Inside you'll find clear explanations of the underlying concepts, practical implementation information, and valuable debugging techniques to keep your PPP connections running smoothly, efficiently, and uninterrupted."

Recommended Textbooks June 26, 2012
Power over Ethernet (PoE) Certification Process Grace Silha

The UNH-IOL acts as the 3rd Party Test Lab for the Ethernet Alliance PoE Certification Program. This Program works to identify PoE Powered Devices (PDs) and Power Sourcing Equipment (PSEs) that are based on IEEE 802.3 PoE specifications and have passed the Ethernet Alliance PoE Test Plan. Learn more about the process in this step by step graphic.

Tutorials February 28, 2022
PoE Technical FAQ

PoE FAQ's

External Links September 23, 2014
Piecing Together the Performance Testing Puzzle Chris Brown & Tim Carlin, UNH-IOL

The latest Dark Reading Ezine focused on Security Testing, features a piece by the IOL "Piecing Together the Performance Testing Puzzle" on pg. 17 NetSecOPEN is developing more security effectiveness test cases as it works to expand and evolve its consensus-driven testing model.

External Links September 6, 2022
Performance Evaluation of TCP over IEEE 802.11 WLANs Sachin Goel

Transmission Control Protocol (TCP) is a communication protocol that is used to provide reliable data delivery between hosts. As TCP is the most highly used transport-layer protocol, many have worked on addressing the issue of performance. Performance issues have been studied in various environments, especially when using 802.11 Wireless Local Area Networks (WLANs). Wireless networks are prone to a higher number of packets loss and corruption. 802.11 WLANs have an equivalently fast acknowledgement mechanism as TCP to ensure reliability of traffic over it. This duplication of functionality between TCP and 802.11 WLAN creates unexpected behaviors that can result in high costs in terms of overall performance. A significant amount of analytical and simulation work has been done in the past to study the behaviour of TCP over 802.11 WLANs. The main contribution of this work is the analysis of TCP interaction in an 802.11 WLAN topology by using real commercial-grade equipments. A testing methodology is designed to do the quantitative performance evaluation in a network topology consisted of wired as well as a wireless connection. The methodology contains test scenarios with different configurable settings on an Access Point (AP) and various controlled impairments in the network topology such as latency, packet drop, noise interference, etc. The performance of TCP is measured in terms of the throughput. This work provides a comprehensive set of experiments to study the behaviour of TCP over 802.11 WLANs. The results can provide insight into the performance cost associated with TCP traffic on 802.11 WLANs under different network environments and configurations on the AP. The results of this work thus have a value to equipment manufacturers and network operators.

Theses September 1, 2006
PCIe_Express_Overview Raju Mishra

Step by step overview on the PCIe Express.

Tutorials September 23, 2014
Overview of UNH EXS for Programmers Robert Russell, Patrick MacArthur

The Extended Sockets API (ES-API) is a specification published by the Open Group that defines extensions to the traditional socket API in order to provide asynchronous I/O and also memory registration for Remote Direct Memory Access (RDMA). These two major new features enable programmers to take advantage of today's multi-core processors and RDMA network hardware, such as InfiniBand, iWARP and RoCE interfaces, in a convenient yet efficient manner.

Tutorials April 15, 2012
Overview of the Internet Protocol Ben Schultz

An overview of the workings of the Internet Protocol.

Tutorials June 4, 2001
Overview of Internet Protocol (Part 2) Ben Schultz

An overview of the workings of the Internet Protocol (Part 2) including specific IPv4 routing protocols.

Tutorials June 4, 2001
OSRM Test Event 2005 Henry He, Takumi Ohba, Kaori Shimizu, Chris Volpe, John Allen, Ankur Chadda, and Scott Larsonk

The third UNH-IOL OSRM test event was designed with a new focus on the failure recovery mechanisms of a GMPLS network. The event provided a vendor-neutral setting that gave participants an opportunity to assess interoperability and valuable feedback to assist them in refining their implementations. Testing included interconnected products demonstrating the functionality of various aspects of explicit route and label control to set up GMPLS traffic engineered most suitable path, control channel failure recovery, data plane failure recovery by multi-layer traffic engineering, end-to-end protection in signaling, and the ability of GMPLS to manage diverse networks with increased scalability.

White Papers July 25, 2005
OSRM Test Event 2004 Henry He, Chris Volpe, Takumi Ohba, Kaori Shimizu, Yumiko Kawashima, and Tom DiMicelli

The second UNH-IOL OSRM test event included seven different companies and was designed in collaboration with Nippon Telegraph and Telephone Corp. (NTT) and the participants to validate and prove GMPLS functionality in a multi-vendor network. This collaboration generated an exceptionally realistic and demanding test suite in line with service providers\' operational demands, rather than simple conformance or interoperability scenarios.

White Papers September 27, 2004
OSRM January 2004 Chris Volpe, Ichiro Inoue, Kaori Shimizu, Yumiko Kawashima, and Tom Dimicelli

The first OSRM event, held at the University of New Hampshire InterOperability Laboratory (UNH-IOL), provided an aggressive carrier-class environment for GMPLS testing including several GMPLS interworking scenarios that had not been achieved in previous multi-vendor test settings. The testing, conducted by the UNH-IOL OSRM test group, involved a variety of test cases that focused on stability testing, control channel fault handling and data channel failure recovery.

White Papers January 26, 2004
OPEN Alliance

The OPEN (One-Pair Ether-Net) Alliance is designed to encourage wide scale adoption of Ethernet-based, single pair unshielded networks as the standard in automotive applications. The jointly developed OPEN Alliance SIG (Special Interest Group) will address industry requirements for improving in-vehicle safety, comfort, and infotainment, while significantly reducing network complexity and cabling costs.

External Links January 2, 2013
octoScope Equipment: Performance & QoE Testing for Wireless Technology

Take a video tour of our wireless testing here at the lab with our state of the art octoScope Test Bed. Our wireless testing focuses on performance and quality of experience for the 802.11 WiFi technologies. Our octoScope testbed includes two 26” octoboxes, and one 38” octoBox with controllable turntable. It can also be configured for video over Wi-Fi testing, mesh testing (self-forming, self-healing functions of a mesh), high speed roaming and other wireless tests.

External Links December 12, 2019
NVMe® Integrator's List Process Grace Silha

We have been a leader and expert in NVMe® Testing Services for several years providing conformance and interoperability testing. In addition, storage vendors from around the world test against NVMe standards to qualify them for the NVMe Integrator's List. The NVMe Integrator's List currently consists of configurations that have proven to be interoperable and conformant to NVMe standards. Here is a quick graphic highlighting the process of getting products on the list.

Tutorials February 28, 2022
NVMe Plugfest Webinar Kerry Munson & David Woolf

In this webinar Kerry Munson & David Woolf, UNH-IOL, will walk thru new test areas and requirements related to NVMe-MI and NVMe-OF. We will also have a walkthrough on IOL INTERACT including recent updates. This will help attendees prepare for the Plugfest held on Oct. 30-Nov. 2, 2017.

Tutorials September 27, 2017
NVMe Integrators List Statistics, Dec 2020 Grace Silha

All things NVMe Integrator's List in this facts graphic. Click to learn and see the evolution of the list, product types listed, and more. The NVMe Integrator's List currently consists of configurations that have proven to be interoperable and conformant to NVMe standards.

Tutorials February 9, 2021
NVMe and NVMe-oF Plugfest Webinar 9 Kerry Munson & David Woolf

Join the UNH-IOL as we walk thru which tests are mandatory for Plugfest #9 based on testing from our previous Plugfest (#8). We will review for both NVMe drives and NVMe-oF targets. In addition, we will walk thru the new tests that have been added for NVMe v1.3 features.

Tutorials May 11, 2018