Knowledge Base

Title Authors Category Updated
802.1D (Classic) Spanning Tree UNH-IOL Bridge Functions Consortium

This presentation provides a high level overview and introduction to Spanning Tree, and related technologies.

Tutorials June 27, 2012
802.1Q VLAN and GVRP UNH-IOL Bridge Functions Consortium

This presentation provides a high level overview and introduction to VLAN and GVRP, and related technologies.

Tutorials June 27, 2012
802.1s Multiple Spanning Tree UNH-IOL Bridge Functions Consortium

This presentation provides a high level overview and introduction to Multiple Spanning Tree, and related technologies.

Tutorials June 27, 2012
802.1X (Port-Based Authentication) UNH-IOL Bridge Functions Consortium

This presentation provides a high level overview and introduction to Port-Based Authentication, and related technologies.

Tutorials June 27, 2012
802.3ad Link Aggregation UNH-IOL Bridge Functions Consortium

This presentation provides a high level overview and introduction to Link Aggregation, and related technologies.

Tutorials June 27, 2012
A Comparison of Efficiency, Throughput, and Energy Requirements of Wireless Anthony Murabito

As energy sources are dwindling, power consumption is a major obstacle facing virtually every industry. Alongside Internet access, wireless computer networks, more commonly known as Wi-Fi networks, have become widely adopted. These wireless networks have found their way into our homes and have also spread to the enterprise market. The goal of this research is to study the power consumption of wireless Access Points, and determine possible means to reduce the energy requirement of the Access Point.

White Papers March 1, 2009
A General-Purpose API for iWARP and InfiniBand Dr. Robert Russell

Remote Direct Memory Access (RDMA) allows data to be transferred over a network directly from the memory of one computer to the memory of another computer without CPU intervention. There are two major types of RDMA hardware on the market today: InfiniBand, and RDMA over IP, also known as iWARP. This hardware is supported by open software that was developed by the OpenFabrics Alliance (OFA) and that is known as
the OpenFabrics Enterprise Distribution (OFED) stack. This stack provides a common interface to both types of RDMA hardware, but does not itself provide a general-purpose API that would be convenient to most network programmers. Rather, it supplies the tools by which such APIs can be constructed.
The Extended Sockets API (ES-API) is a specification published by the Open Group that defines extensions to the traditional socket API which include two major new features necessary to exploit the advantages of RDMA hardware and the OFED stack: asynchronous I/O and memory registration.

The UNH-EXS interface is a multi-threaded implementation of the ES-API plus additional extensions, which enables programmers to utilize RDMA hardware via the OFED stack in a convenient, relatively familiar manner. The UNH-EXS interface is implemented entirely in user space on the Linux operating system. This provides easy porting, modification and adoption of UNH-EXS, since it requires no changes to existing Linux kernels. We present results on the performance of some benchmark applications using the UNH-EXS interface on both iWARP and InfiniBand hardware.

White Papers December 13, 2012
A Performance Study to Guide RDMA Programming Decisions Patrick MacArthur and Dr. Robert Russell

This paper describes a performance study of Remote Direct Memory Access (RDMA) programming techniques. Its goal is to use these results as a guide for making "best practice" RDMA programming decisions. Infiniband RDMA is widely used in scientific high performance computing (HPC) clusters as a low-latency, high-bandwidth, reliable interconnect accessed via MPI. Recently it is gaining adherents outside scientific HPC as high-speed clusters appear in other application areas for which MPI is not suitable. RDMA enables user applications to move data
directly between virtual memory on different nodes without operating system intervention, so there is a need to know how to incorporate RDMA access into high-level programs. But RDMA offers more options to a programmer than traditional sockets programming, and it is not always obvious what the performance tradeoffs of these options might be. This study is intended to provide some answers.

White Papers January 18, 2013
Advanced Digital Signal Processing and Noise Reduction Saeed V. Vaseghi

From the back cover: "Signal processing and noise reduction are at the core of telecommunications and information processing systems. With the increasing use of digital cellular mobile systems in a variety of adverse environments, noise reduction is becoming a particularly important aspect of communication system design. This second edition provides a thoroughly revised and expanded introduction to the fundamentals of random processes, Bayesian modelling, and noise reduction. The subject is covered in a graphical and mathematically accessible manner with the emphasis on Bayesian inference and its application to noise reduction."

Recommended Textbooks June 26, 2012
Advantages and Testing Considerations of a Converged DCB Network Presentation Peter J. Scruton

Peter participated in the 2012 Ethernet Technology Summit in San Jose, California as a panelist in one of the Sessions. The Session focus was on the Continuing Role of Ethernet in Storage.

External Links December 4, 2012
An Efficient Method for Stream Semantics over RDMA P. MacArthur and R. Russell

Most network applications today are written to use TCP/IP via sockets. Remote Direct Memory Access (RDMA) is gaining popularity because its zero-copy, kernel-bypass features provide a high throughput, low latency reliable transport. Unlike TCP, which is a stream-oriented protocol, RDMA is a message-oriented protocol, and the OFA verbs library for writing RDMA application programs is more complex than the TCP sockets interface. UNH EXS is one of several libraries designed to give applications more convenient, high-level access to RDMA features. Recent work has shown that RDMA is viable both in the data center and over distance.

One potential bottleneck in libraries that use RDMA is the requirement to wait for message advertisements in order to send large zero-copy messages. By sending messages first to an internal, hidden buffer and copying the message later, latency can be reduced at the expense of higher CPU usage at the receiver. This paper presents a communication algorithm that has been implemented in the UNH EXS stream-oriented mode to allow dynamic switching between sending transfers directly to user memory and sending transfers indirectly via an internal, hidden buffer depending on the state of the sender and receiver. Based on preliminary results, we see that this algorithm performs well under a variety of application requirements.

White Papers May 21, 2014
An ITU-T G.994.1 Protocol Analysis Tool For ADSL Matthew Langlois (UNH-IOL), Dr. Michael Carter, Dr. William Lenharth, and Scott Valcourt

One of the most commonly deployed DSL variants is ADSL. Despite this fact, deployment of new robust and reliable ADSL services is increasingly difficult due, in part, to the physical limitations of the copper telephone system infrastructure, and also in part to the lack of useful ADSL network debugging tools. ADSL service providers and technicians currently lack a device capable of decoding physical layer signaling and displaying actual physical layer parameters and statistics associated with a live ADSL connection, independent of the end stations. Similar devices used in other network technologies are often referred to as protocol analyzers. The intent of this paper is to illustrate how Matlab [1], in conjunction with a DSP or a PC, can be used to create an effective ADSL handshaking protocol analyzer based on ITU-T G.994.1 (G.hs) [2]. G.hs conformance is critical in establishing a successful ITU-T G.992.1 (G.dmt) [3] based ADSL connection.

White Papers November 4, 2002
Basics of DSL Bonded Physical Layer Testing Lincoln Lavoie (UNH-IOL)

An overview to DSL Bonded Physical Layer Testing.

Tutorials February 24, 2012
BER Testing: How Many Bits Are Enough? Andy Baldman

The purpose of this article is to discuss the concept of Bit Error Ratio testing, and will explain, using a minimum amount of math, the answer to the fairly common question: "How many bits do I need to send in order to verify that a devices exceeds a given BER?"

Theses June 29, 2012
Broadband Forum Kieffer Quitayen

Broadband Forum is an international industry consortium of nearly 200 leading service providers, equipment manufacturers and other interested parties, focused on developing the full potential of broadband DSL to meet the needs of the mass market.

External Links June 26, 2012
CERN - High Speed Interconnect Server

Browse through some of the technologies and functions used in high-performance data acquisition systems for high-energy physics experiments.

External Links April 13, 2005
Clause 24: 100BASE-X Physical Coding Sublayer (PCS)

An overview of the 100BASE-TX PCS created by the UNH-IOL.

Tutorials January 1, 2004
Clause 28 & 40 Auto-Negotiation: An Introduction to the Auto-Negotiation process Jeff Lapak

A brief introduction to auto-negotiation created by the UNH-IOL.

Tutorials January 1, 2004
Clause 28 Auto-Negotiation

A brief tutorial the covers the basics behind Clause 28:Auto-Negotiation.

Tutorials June 29, 2012
Clause 28 Auto-Negotiation Basic Introduction Matthew Hersh

View this for a basic introduction to Copper and Fiber Ethernet Auto-Negotiation.

Tutorials August 5, 2005
Clause 37: Auto-Negotiation David Estes

An introduction to the Clause 37 Auto-Negotiation Process.

Tutorials January 1, 2004
Clause 40 Auto-Crossover White Paper Matthew Hersh

A brief tutorial that covers the basics behind the Clause 40 Automatic MDI/MDI-X Configuration.

Tutorials April 18, 2006
Clause 40: 1000BASE-T Physical Medium Attachment (PMA) Sublayer

1000BASE-T PMA overview (location in the OSI stack, interface with PCS, interface with Auto-Negotiation, PAM-5 Encoding Scheme, PMA Sublayers Functionality and Functions, and PMA Electrical Specifications).

Tutorials January 1, 2004
Clock Synchronization Terminology Jeff Laird

Terms used when discussing PTP

White Papers June 28, 2012
Comparison of DCBX Versions Daniel Shea

A comparison of the baseline versus the IEEE standard versions of Data Center Bridging Capabilities Exchange.

Tutorials September 11, 2012