Knowledge Base

Testing scenarios, caveats and issues encountered in testing converged or "triple play" (voice, video, data) services and security in converged enterprise-class deployment scenarios.

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

The second MPLS World Congress interoperability event included 10 different companies and was hosted by the MPLS Forum and Frame Relay Alliance at the EANTC labs in Berlin, Germany. The demonstration, held at the MPLS World Congress in Paris, proved that MPLS Layer 2 Ethernet-based VPNs are ready for large scale deployment. Also demonstrated were minimal MPLS ping and traceroute implementations.

The November test set explored several new areas, including VoIP via Session Initiation Protocol (SIP), wireless LANS and streaming video via Multicast. Particular areas of testing included IPsec, DNS, DHCP, iSCSI, routing, tunneling and QoS. The November testing was attended by 16 different vendors, and results proved that IPv6 is stable and capable of running key data communications applications (voice-based services and multicast).

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.

An overview of how the UNH-IOL Fast Ethernet and Gigabit Ethernet Consortia create the cable plants that are used during InterOperability testing for 1000BASE-T devices.

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.

Phase II of the Moonv6 project established the largest native IPv6 network in the world. The second phase of the project was able to demonstrate high speed links, advanced routing functionality, firewalls, QoS, and other key features. More than two dozen organizations participated in Phase II, and testing was facilitated by engineers from nine separate sites.

SuperDemo 2004 was the product of a partnering of the Multiservice Switching Forum (MSF) with the MPLS & FR alliance. Eleven companies participated in expanded testing including advanced service provider applications. The collaboration of the MSF and the MFA took the meaning of success to another level in the industry. The Multi-Vendor MPLS infrastructure was constructed for stability and reliability. The Demonstration of VoIP services across this network clearly conveyed a feeling of resilience.

The performance of DSL transceivers can be impaired by interference from other transceivers operating over wires in the same binder group. It is therefore important to test DSL transceivers in the presence of crosstalk, which can be simulated in a programming environment such as MATLAB. The simulated crosstalk can then be exported to an arbitrary waveform generator (AWG) for injection onto the line through a high-impedance noise injection circuit. This document describes a method of crosstalk simulation and calibration whereby white gaussian noise (WGN) is passed through a frequency-domain filter that gives the noise the spectral characteristics of crosstalk. The crosstalk is calibrated by measuring its power with a vector signal analyzer (VSA) and adjusting the output level on the AWG to achieve the desired noise power. By using MATLAB to estimate the simulated crosstalk power in the same manner as the VSA, the calibration can be performed in MATLAB without taking actual measurements.

iFCP is one form of storage over TCP/IP that allows hosts and Fibre Channel storage devices to communicate directly. It is an encapsulation protocol that dictates the means by which Fibre Channel frames become the payload in an iFCP message. In addition, iFCP introduces a few new types of messages for purposes of control. This thesis is comprised of the design and implementation of iFCP end devices. The initiator has been implemented as a software module that behaves like a Fibre Channel Host Bus Adapter with an attached encapsulator. The target has been implemented as a stand-alone software program that acts both as an encapsulator and as a Fibre Channel switch that is attached through a generator to a Fibre Channel disk.

Tutorial generated by the IEEE EFM task force.

This interoperability evaluation focused on the transport of differentiated services on a multi-vendor MPLS backbone supporting MPLS traffic engineering. The MPLS World Congress 2004 demonstrated differentiated services over MPLS and MPLS traffic engineering. Multi-vendor MPLS/BGP VPN\'s and Layer 2 Ethernet VPN\'s (Martini and VPLS) were configured to prove that services were traffic engineering-enabled and could process differentiated services.

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.

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

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

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).

An introduction to the Clause 37 Auto-Negotiation Process.

Phase I of Moonv6 demonstrated that current IPv6 networking technology is stable, resilient and ready for integration with today\'s Internet. The event was attended by more than thirty different organizations and confirmed several stable and interoperable implementations of IPv6, and proved that IPv6 is ready to be deployed on a global scale. Specific aspects of IPv6 included common network applications, base specifications, transition mechanisms, routing protocols, security and mobility.

The United States Commerce Department's National Telecommunications and Information Administration (NTIA) spectrum chart, dated October 2003, depicts the radio frequency spectrum allocations to radio services operated within the United States.

SuperDemo 2003 was the worlds most advanced and comprehensive live test of multiple MPLS services operating concurrently across a multi-vendor MPLS network. The MPLS/FR Alliance SuperDemo included 14 different companies showcasing MPLS services and features such as VPLS, ATM/FR/Ethernet over MPLS, BGP MPLS VPNs and Fast re-route.

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

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.

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.

This presentation provides an overview and comparison of the two proposed VDSL modulation schemes.