Certified Media Test Field Engineer

Certified Media Test Field Engineer
Pruebas en Sist. de Cableado y DSPs 01 de abril de 2017

Fluke Corporation - José M. Bonilla
Agenda Entendiendo los Sistemas de Cableado Estructurado Mediciones de Sistemas Cat-5 y más Demostración del DSP-4000 Práctica con el DSP-4000 Pruebas sobre Fibra Optica Examen escrito 01 de abril de 2017 Fluke Corporation - José M. Bonilla

Entendiendo los Sistemas de Cableado Estructurado
Fundamentos de Desempeño de Redes This presentation was part of a panel session on improved cabling performance, part of the January 1998 BICSI Conference in Orlando, Florida. It is an introduction on what the improvements mean in terms of overall link performance.

Pruebas en Campo para Sistemas de Cableado de Redes de Alto Desempeño
Revisión de Pruebas y Estándares

Objetivos Análisis de los requerimientos de transmisión necesarios para redes de par trenzado. Revisión de los estándares actuales (Cat 5, Class D: 1995) Status y requerimientos de los estándares en desarrollo (Cat 5e, Cat 6,Class D: 1999, y Class E) Requerimientos para Gigabit Ethernet 01 de abril de 2017 Fluke Corporation - José M. Bonilla

¿Por qué probar el cableado?
¿El sistema de cableado instalado cumple con los criterios o requerimientos necesarios para un buen desempeño de transmisión (voz, video y datos) en las redes actuales y futuras? ¿El personal capacitado cumple con la eficiencia esperada? 01 de abril de 2017 Fluke Corporation - José M. Bonilla

¿Por qué probar el cableado?
Lo que compro ¿es lo que realmente estoy pagando? Lo que vendo ¿es lo que mi cliente realmente espera recibir? ¿Le va a servir a mi cliente lo que he instalado? ¿Estamos haciendo bien nuestro trabajo?? 01 de abril de 2017 Fluke Corporation - José M. Bonilla

¿Por qué Pruebas en Campo?
¿Los enlaces instalados proveen los criterios o características de desempeño “esperadas” para una transmisión confiable? Los resultados están determinaos por: La calidad y desempeño de los “componentes” Cable Dispositivos de Conectividad Diseño, calidad y mano de obra de la instalación EMI (ruta, localización) del cableado 01 de abril de 2017 Fluke Corporation - José M. Bonilla

“Certificación” del Cableado
Comparar el desempeño de un sistema de cableado instalado contra un estándar (resultados esperados) Los sistemas de cableado incluyen cables “en la pared”, conectores, cables de parcheo, cross-connects, y paneles de parcheo cer·ti·fi·car v. t. a. Dar una cosa por segura, afirmar. b. Hacer cierta una cosa por medio de un documento. Garantizar que cumple o alcanza un estandar. Ver sinónimos de probar. [Source: American Heritage Dictionary] Emphasize that in order to “certify”, one must have a standard. And standards are only standards because a great number of people in the industry accept and abide by them. Another reason to emphasize the importance of standards is the fact that some users would like the tester to make all its testing decisions based on just the vendor and model number of the cabling to be tested. The TIA (Telecommunications Industry Association) standards we will discuss differentiate between different link types with different pass/fail criteria. There are several standards and we support a large variety of them in the DSP Series testers. The standards fall into two categories: (1) Generic cabling standards issued by industry standards committees such as the TIA in the USA or ISO/IEC in the international market. (2) Network specific cabling requirements issued by the network standards or committees. An examples of the latter is the 10BASE-Tstandard defined in IEEE 802.3i. 01 de abril de 2017 Fluke Corporation - José M. Bonilla

Papel de los Estándares
Especificaciones de los Componentes Define el desempeño y grado de cables, conectores y hardware Ejemplo: ANSI/TIA/EIA 568-A, ISO IEC 11801 Estándares de Red (Aplicaciones) Define los requerimientos de desempeño para todos los elementos de una red Ejemplo: IEEE 802, ATM-PHY Estándares de Pruebas y Mediciones Definen la metodología de prueba, herramientas y procedimientos Ejemplo: TSB-67 01 de abril de 2017 Fluke Corporation - José M. Bonilla

Estándares ANSI/TIA/EIA
568-A Commercial Building Telecommunications Cabling Standard 569 Commercial Building Standards for Telecommunications Pathways and Spaces 570 Residential and Light Commercial Telecommunications Wiring Standard 606 The Administration Standard for the Telecommunications Infrastructure of Commercial Buildings 607 Commercial Building Grounding and Bonding Requirements for telecommunications 01 de abril de 2017 Fluke Corporation - José M. Bonilla

ANSI/TIA/EIA 568-A Título: “Commercial Building Telecommunications Cabling Standard” Sistema de cableado genérico para telecomunicaciones que soportará ambientes multi-producto y multi-fabricante Define: Especificaciones de desempeño para componentes (Categorías) Guías para el diseño de cableado estructurado Guías para las prácticas de instalación Especificaciones de desempeño de enlaces instalados 01 de abril de 2017 Fluke Corporation - José M. Bonilla

Especificaciones del TIA-568A
Reglas de Diseño: Configuración y longitud del enlace Basic Link (90 metros, 294 pies) Channel (100 metros, 328 pies) Tensión y sugesión del cable Interferencia Cercanía a sistemas de potencia Guías de Instalación: Radios de curvatura Fuerza de Jalado/Tirado Terminación y Conectorización 01 de abril de 2017 Fluke Corporation - José M. Bonilla

ISO IEC IS 11801 Título: Information Technology – Generic cabling for customer premises cabling Propósito: Definir un sistema independiente de la aplicación, sistema abierto Definir un esquema de cableado flexible, de manera que las modicifaciones sean fáciles y económicas Definir un sistema de cableado que soporte las aplicaciones actuales y que sea una base para el desarrollo de productos futuros 01 de abril de 2017 Fluke Corporation - José M. Bonilla

Límites de Longitud del Cableado
Límite Total de Longitud: 100 Metros Max HUB/SWITCH WORK AREA CORDS 3m Max PATCH CORDS 7m Max* Cableado Horizontal 90 Metros Max WIRING CLOSET (TC) WORK AREA *La longitud total combinada de los patch cords en el TC no debe rebasar los 7 mts. 01 de abril de 2017 Fluke Corporation - José M. Bonilla

Beneficios de Compatibilidad contra Estándares
Seguridad de que el sistema de cableado soportará aplicaciones basadas en estándares Las aplicaciones de red futuras serán desarrolladas basadas en la infraestructura de los estándares Administración simplificada Reducir el Costo Total de Propiedad (TCO) Prevensión de crecimientos futuros 01 de abril de 2017 Fluke Corporation - José M. Bonilla

Modelo de Enlace de Datos
Transmisor Receptor Medio de Transmisión Transmisor, medio y receptor forman un sistema Meta: Conjuntar capacidades de los compo-nentes para asegurar transmisiones confiables Fuerza característica de señal que sale del transmisor Fidelidad de transmisión de la señal a través del medio Capacidad del receptor para capturar y decodificar la señal 01 de abril de 2017 Fluke Corporation - José M. Bonilla

Técnicas de Señalización
Transmisión en Banda Base 1 NRZ Señalización Digital: Señales en el enlace de cable formadas por niveles de voltaje “discretos” Las señales representan información digitalmente codificada (Datos binarios) Todo el ancho de banda del canal está dedicado 01 de abril de 2017 Fluke Corporation - José M. Bonilla

Senoidales vs. Pulsos Period + = Using Fourier analysis, it can be demonstrated that a pulse “contains” a large number of sinusoidal harmonics of the base signal with the same period (frequency) as the pulse. The test stimulus signal used by the DSP-100 is not a series of frequencies but a pulse. The pulse furthermore resembles closely the signaling on a network. + +…… 01 de abril de 2017 Fluke Corporation - José M. Bonilla

Representación de la Señal
Time Domain Frequency Domain 1 Freq. (MHz) 01 de abril de 2017 Fluke Corporation - José M. Bonilla

Time Domain Frequency Domain 1 3 Freq. (MHz) 01 de abril de 2017 Fluke Corporation - José M. Bonilla

Time Domain Frequency Domain 1 3 5 7 Freq. (MHz) 01 de abril de 2017 Fluke Corporation - José M. Bonilla

Densidad Espectral de la Codificació NRZ Dominio del Tiempo Dominio de la Frecuencia Frec. (MHz) Tiempo 01 de abril de 2017 Fluke Corporation - José M. Bonilla

Modelo de Comunicación
Señal Transmitida Transmisor Medio de Transmisión Dispositivo de Envío Información Dispositivo de Recepción Receptor Información Señal Recivida 01 de abril de 2017 Fluke Corporation - José M. Bonilla

Especs. de Frecuencia Megahertz (MHz) no es igual a Megabits por segundo (Mbps) MHz: Es una unidad de Frecuencia Describe las señales electricas Pertenece al medio físico Mbps: Una tasa de transmisión de datos Describe la “salida” alcanzada por un sistema (electrónica, software y medio) Pertenece a la capa 1 y superiores del Modelo OSI 01 de abril de 2017 Fluke Corporation - José M. Bonilla

Especs. de Frecuencia Ancho de Banda: El rango de frecuencias para el cual un dispositivo o medio entrega cierto nivel de desempeño La capacidad de información de un canal en Mbps está determinada por: El ancho de banda en MHz disponible La eficiencia de la señal codificada Lo complejo de la electrónica 01 de abril de 2017 Fluke Corporation - José M. Bonilla

MHz es el ANCHO del “tubo” Mbps es el FLUJO de datos
En otras palabras… MHz es el ANCHO del “tubo” Mbps es el FLUJO de datos 01 de abril de 2017 Fluke Corporation - José M. Bonilla

Requerimientos de Aplicaciones
One of the factors of confusion existing and exploited by one or our competitors is the fact the Mbps and MHz are NOT identical. One is a measure of the rate of data transfer (in bits per second), the other is a measure of the signal carrying capacity of the transmission medium (bandwidth in MHz). The two numbers happen to be the same for the existing Ethernet (10Mbps) and Token Ring LAN standards due to the signal encoding techniques used (Manchester and Differential Manchester, respectively). The “fast” network standards are all using different signal encoding techniques that require a smaller number in the signaling rate than the rate of data transfer in bits per second. Maybe some of your audience will be familiar with the difference between baud and bits per second in the modem standards which is an analogous situation. The competitive issue arises from the fact that Scope Communications has introduced the Wirescope 155 which tests to 155 MHz to supposedly “certify” that the cabling system will perform for the much ballyhooed ATM standard. The specification for the physical layer (cabling system) in ATM states that UTP Cat 5 satisfies the transmission requirements for ATM. 01 de abril de 2017 Fluke Corporation - José M. Bonilla

Especs. de Componentes 01 de abril de 2017 Fluke Corporation - José M. Bonilla

Vistazo a las actividades de la IEEE en Gigabit Ethernet
IEEE 802.3z Gigabit Ethernet empleando Fibra Optica como medio IEEE 802.3ab Desarrollo de 1000BASE-T Gigabit Ethernet utilizando como medio cableado par trenzado de cobre Cat-5 para enlaces de no más de 100 mts. The support from the structure was evident during the June 1997 meeting of the US Technical Advisory Group (US TAG). This group represents the US to international standards group meetings (ISO/IEC JTC 1/SC 25/WG 3 in particular). US based organizations can become a member of the US TAG. Formally, the TIA is not a member of the US TAG. However, the same people that go to TIA meetings go also to the US TAG meetings and therefore this is not really an issue. The US TAG is anticipating request to take a position on the German Cat 6 proposals during the ISO/IEC meetings in Bazios Brasil in June The decision was to request reservation of the “cat 6” designation for enhanced category 5 with requirement specifications over 100 MHz, and assign “cat 7” to the German DIN proposal. Fluke is a member of the US TAG, and also a voting non-member of the TIA (we are a “non-member” because Fluke does not produce cable or connectors; Fluke has full voting rights on the TIA standards however). 01 de abril de 2017 Fluke Corporation - José M. Bonilla

Conclusion publicada en Agosto de 1999.
IEEE 802.3ab Define estándar 1000BASE-T Gigabit Ethernet sobre sistemas de cable par trensado Categoria 5 Utilizará los 4 pares en modo Full-Duplex Emplea cancelación ténicas de cancelación de NEXT (como en 100BASE-T2) Método de codificación de la señal Multi-nivel (PAM-5) IEEE 802.3ab is now fully devoted to the development of 1 Gbps Ethernet on category 5 twisted pair cabling. All 4 wire pairs in the standard 4-pair cable will be used, and transmission will be full duplex on all wire pairs. NEXT cancellation techniques will be implemented, like were used to define a 2 wire-pair on category 3 solution (called 100BASE-T2 - this standard has no practical equipment being produced). The intent is to nail down the encoding methods to be used at the July 1997 Maui meeting. The overall goal is to obtain a completed standard by late 1998. Conclusion publicada en Agosto de 1999. 01 de abril de 2017 Fluke Corporation - José M. Bonilla

Pruebas en Campo para Sistemas de Cableado UTP de Alto Desempeño
Parámetros de Desempeño Pruebas de Evaluación

Definición de: “Channel”
2 transiciones en cada extremo USER’S PATCH CORD PATCH PANEL HORIZONTAL CABLE Telecom Outlet WIRING CLOSET WORK AREA Channel End Under carpet or furniture connector C.P. The first link model is called the Channel. The Channel (which used to be called the “User’s Link” at one point in time) is the end-to-end link which connects a network station (PC, Workstation, printer, server, etc.) to the network (Hub, MAU, or wiring concentrator). This, of course, is the link that the end-user is interested in. Note that the standard excludes the end-connectors from the link definition. The end-connector, practically always an 8-pin modular jack (RJ-45 connector), is truly only half of the plug-socket pair which makes up the connection between the link and the end-user equipment. This connection is viewed as an integral part of -- and the responsibility of -- the end-user equipment. The same reasoning holds for the field cable testers. When the tester is connected to the link, the performance of the connection is as much a function of the characteristics of the tester as it is a function of the plug at the end of the link. The standard requires that the effect of this connection is to be excluded. The 8-pin modular connection at the link contributes an unpredictable amount of crosstalk which can lead to a sizable error in the measurements (1.8 dB or more). This is one of the main reasons why existing cable testers using 8-pin modular connectors (RJ-45) and the sweep frequency method to measure Near-End Crosstalk (NEXT), do not meet the stringent accuracy requirements for Level II testers. The Fluke DSP-100 is constructed with RJ-45 mating sockets to be able to connect to a Channel directly. The innovative digital technology of the DSP-100 compensates the effect of the connectors to meet the proposed accuracy level II requirements. We will discuss this technology later in the presentation. The next slide summarizes the link issues. 01 de abril de 2017 Fluke Corporation - José M. Bonilla

Definición de: “Basic Link”
Una transición en cada extremo Longitud máxima de patch cords de prueba de 2 mts. WORK AREA Link End TESTER PATCH CORD PATCH PANEL HORIZONTAL CABLE Telecom Outlet WIRING CLOSET The second of the two link models defined in the standard is called the Basic Link. The Basic Link is characterized by the fact that only one transition is present at either end of the cabling link (The wall outlet on one end and the patch panel termination on the other end). This link includes the portion (from patch panel in the wiring closet to wall outlets in the work areas) for which a cable installer is typically held responsible. That is why this link at one point in time was referred to as the “Contractor’s link”. The test limits for this link differ from the channel which includes the end-user patch and equipment cables. The Basic Link is typically tested using the patch cords belonging to the field tester (shown in red). Again, the end-connection is not part of the link. All of our competitors, using the older analog (swept frequency) approach to cable testing have modified their second generation testers by replacing the 8-pin modular connector with a so-called “LOW NEXT” connector. (Note that LOW NEXT is not NO NEXT -- LOW is a relative term). This modifications allows these competitors to meet the accuracy Level II for the basic link but not for the channel. More on this later. 01 de abril de 2017 Fluke Corporation - José M. Bonilla

Definición: “Permanent Link”
Los resultados de prueba no incluyen las contribuciones de los cables del equipo Link End TESTER PATCH CORD Telecom Outlet WORK AREA Patch Panel HORIZONTAL CABLE WIRING CLOSET C.P. The second of the two link models defined in the standard is called the Basic Link. The Basic Link is characterized by the fact that only one transition is present at either end of the cabling link (The wall outlet on one end and the patch panel termination on the other end). This link includes the portion (from patch panel in the wiring closet to wall outlets in the work areas) for which a cable installer is typically held responsible. That is why this link at one point in time was referred to as the “Contractor’s link”. The test limits for this link differ from the channel which includes the end-user patch and equipment cables. The Basic Link is typically tested using the patch cords belonging to the field tester (shown in red). Again, the end-connection is not part of the link. All of our competitors, using the older analog (swept frequency) approach to cable testing have modified their second generation testers by replacing the 8-pin modular connector with a so-called “LOW NEXT” connector. (Note that LOW NEXT is not NO NEXT -- LOW is a relative term). This modifications allows these competitors to meet the accuracy Level II for the basic link but not for the channel. More on this later. 01 de abril de 2017 Fluke Corporation - José M. Bonilla

TIA - Los Nuevos Estándares
Cat 5 Recomendaciones Actuales requeri-mientos de TIA TSB-67 se conser-van igual. Las Recomenda-ciones TIA TSB-95 son agregadas para 1000BASE-T: RL, ELFEXT, and PSELFEXT Pruebas hasta 100 MHz Nuevos asuntos incluidos en un “addendum” Cat 5e “Enhanced” Cat 5 Prueas hasta 100 MHz Un mejor están-dar TIA-568-A-5 con mejor desempeño en: NEXT, PSNEXT, RL, ELFEXT and PSELFEXT. Propuesta Cat 6 Pruebas hasta 250 MHz Requerimientos de desempeño para cable y conector bajo estudio. El mayor reto es el conector. “Mejora” típica por un factor de 2 The following structure of high performance levels of twisted pair cabling is emerging: 1. First there is the “new” cat 5 standard. It contains the current requirements for cat 5 cabling, but this standard update will also contain requirements for currently undefined parameters such as FEXT and Return Loss - more about these parameters later. This development is driven by the needs to support 1 Gbps Ethernet on 100 meters twisted pair category 5 cabling. The IEEE 802.3ab committee keeps insisting that 1000BASE-T will run on currently installed category 5 cabling. It is expected that currently installed category 5 cabling (with two 8-pin modular connections (RJ-45)) will meet the test limits for the additional requirements. 2. Then there is the “enhanced” category 5 cabling. The existing requirements for attenuation and NEXT have been tightened up. Crosstalk performance will have to meet Power Sum specifications. The new performance parameters specified to support 1000BASE-T will also be specified with better performance for Cat 5e. Note that these requirements will continue to be specified up to 100 MHz. 3. Cat 6. It is expected that the link requirements will be specified up to either 200 MHz or 250 MHz. The goal of the Cat 6 standard is to specify a link that delivers at 200 MHz the performance that is available today with a Cat 5 link at 100 MHz. A major challenge remains to define Cat 6 performance for connecting hardware. Proprietary high performance links or solutions are available in the market today. However, this performance is only guaranteed if all components are purchased as a system from the same vendor. 01 de abril de 2017 Fluke Corporation - José M. Bonilla

Comparación de Desempeño
Mínimo para 1000Base-T Una especificación más completa 01 de abril de 2017 Fluke Corporation - José M. Bonilla

Especificación más completa Garantizado para 1000BASE-T 01 de abril de 2017 Fluke Corporation - José M. Bonilla

Garantizado para 1000Base-T Mejora considerable de desempeño 01 de abril de 2017 Fluke Corporation - José M. Bonilla

Niveles de Precisión Nivel I Especificado en el TSB67 Nivel II Nivel IIe Especificado en el Adendum 5 de la 568-A Nivel III Especificado en el 568-B.2(draft 7) 01 de abril de 2017 Fluke Corporation - José M. Bonilla

Nivel III 01 de abril de 2017 Fluke Corporation - José M. Bonilla

Pin/Par Asignación - T568A
Top view of 8-pin modular plug Front view of 8-pin modular jack Pair 2, (Orange) Pair 3, (Green) Pair 1, (Blue) Pair 4, (Brown) This diagram is included for completeness sake. It illustrates the “preferred” wiring method of 8-pin modular jacks and is called the T568A wiring scheme or wiring pattern. 01 de abril de 2017 Fluke Corporation - José M. Bonilla

Pin/Par Asignación - T568B
Top view of 8-pin modular plug Front view of 8-pin modular jack Pair 2, (Orange) Pair 3, (Green) Pair 1, (Blue) Pair 4, (Brown) This diagram is included for completeness sake. It illustrates the “alternate” wiring method of 8-pin modular jacks which is called the T568B wiring scheme or wiring pattern. This is also referred to as the AT&T wiring scheme because it was proposed and defended by AT&T. We believe that the T568B is most common in installations throughout the USA. 01 de abril de 2017 Fluke Corporation - José M. Bonilla

Mapa de Pares Correcto 01 de abril de 2017 Fluke Corporation - José M. Bonilla

Par Invertido A Reversed Pair wiring error is found when the polarity of the two wires in a pair is not maintained consistently from one of the link to the other. Telephone technicians refer to the wires in a pair as Tip and Ring. Therefore, in order to clarify this problem, you may want to describe it as a tip/ring reversal (note that the tip and ring terminology is typically not used in data cabling). 01 de abril de 2017 Fluke Corporation - José M. Bonilla

Pares Transpuestos As shown in this picture the wire pairs on pins 1,2 and 3.6 are NOT providing a connection from end to end. Instead, pins 1,2 at one end are connected to pins 3,6 at the other end and vice versa. This is the most common way in which a transposed pair is created. The wiring scheme at one end is T568A while the connection at the other end is T568B. The moral of this story is that the same wiring convention should be used throughout a building. This particular example serves a good purpose in the case you need a “cross-over cable” to connect two hub (when the hub does not provide the cross-over internally with a “uplink” port and switch) Ejemplo: Mezcla los estándares T568A y T568B = Problemas 01 de abril de 2017 Fluke Corporation - José M. Bonilla

Resultado en un DSP... Pares Transpuestos The DSP Series testers show the connections as they are detected in the link under test. The transposed error indicates that the wire pair connected to pins 1 and 2 at the near end (left hand side in the diagram indicates the connector plugged into the tester -- also called the near end) is connected to the pin number 3 and 6 at the far end and vice versa. A typical error if the two allowable wiring standards are mixed within a link or link segment. 01 de abril de 2017 Fluke Corporation - José M. Bonilla

Pares Partidos / Divididos
Caudado por conectar cables de diferentes pares en pines “pareados” Provoca un alto nivel de Near-End Crosstalk Spit Pairs are the type of installation error that cannot be detected using a simple continuity test yet it has devastating effects on the transmission quality of the cabling link. A DMM or a DC Continuity test wouldn’t identify this type of wiring error since the pin-to-pin connectivity is correct. However, due to the excessive crosstalk of such connection, this cable will cause many problems, if it supports any network transmission at all. The next slide shows the effect of this wiring scheme on the pairing as it is expected by the electronics. This picture shows how such an error is created: people talk about “straight through” wiring. This may seem a logical way of doing things but it does not meet the standard way which is expected by all of the electronics connected to the cabling. 01 de abril de 2017 Fluke Corporation - José M. Bonilla

Pares Partidos / Divididos
The wiring method shown in the previous slide creates the connections that are shown in a slightly different way in this slide. This picture more clearly demonstrates the fact that the electronic circuits using the link expect to drive (or detect) a “balanced signal” on pin numbers 3,6 and 4,5. Instead the wires connecting pins 3 and 6 from one end to the other are not twisted together. This configuration violates the balance requirement which is detected due to the excessive amount of crosstalk between the wires connecting 3,6 and those connecting 4,5 from one end to the other. Note that a simple continuity test would find nothing wrong with this link. 01 de abril de 2017 Fluke Corporation - José M. Bonilla

Pantalla del DSP... Pares Partidos As stated in the notes of the previous slide, a split pair error cannot be detected by a simple continuity test. Therefore, the wire map graphic shows continuity from pin to pin but the wires in the picture are intertwined to indicate the split pair problem. The tester furthermore adds the comment line that a split pair has been detected. It should be noted that the tester diagnoses the “split pair” based on the magnitude of the crosstalk problem combined with the fact that the cable passes a basic continuity test. 01 de abril de 2017 Fluke Corporation - José M. Bonilla

Medición de Longitud y Verificación de Impedancia
Time Domain Reflectometry TDR Scan Pulse open Transmitted pulse Reflected pulse short terminated Field testers measure the electrical length of a data link. This electrical measurement is based on a time measurement that is called Time Domain Reflectometry (TDR). TDR is based on the fact that at a location along a cabling link where the impedance of the cable changes, part of the signal is reflected back to the source. A cable with a uniform characteristic impedance which is properly terminated will not produce any reflections. That is the desired result in an operating LAN. Reflections are a source of signal deterioration that may cause the transmissions to fail and that result in re-transmissions or total breakdown of communications. Any discontinuity (change) in the characteristic impedance will produce a reflection; such a fault is called an anomaly. The cable length is measured after the remote unit “opens” the cable at the far end; this open circuit represents a very significant change in impedance. The reflection caused at the open end of the cable, travels back to the tester. The electrical length measurement consists of a time delay measurement. In order to determine the length one must know the velocity with which the electrical pulse travels along the cable. Travel-time * Constant-speed = distance (twice the length of the cable). Some customers judge the accuracy of the tester by the accuracy of the length measurement. This is very unfortunate. Length is the least important of the measurements and is affected by many factors, not the least of which is the accuracy of the factor called NVP. (See next slide). Since the electrical length measurement consists of a timing measurement, the main accuracy parameter for the tester is its timing accuracy and resolution. Measuring a short patch cord will be less accurate than a full-length link. The roundtrip propagation delay for a patch cord is typically less than 15 nsec. With 1 nsec resolution, the maximum timing error is just less than 1 nsec. 1 in 15 is an error of 7% without the cumulative effect of the uncertainty caused by NVP. (No Reflection) 01 de abril de 2017 Fluke Corporation - José M. Bonilla

Nominal Velocity of Propagation (NVP)
La velocidad a la cual la señal viaja en el cable, expresada como un porcentaje de la velocidad de la luz en el vacio. velocidad del viaje del pulso en el cable NVP = The Nominal Velocity of Propagation or NVP is the parameter that expresses the speed with which an electrical signal travels along the link. It is expressed relative to the speed of light in vacuum. Typical numbers for UTP cables range from 62% to 72%. Fluke instruments, like the Fluke 650, 652, and the DSP Series provide the typical NVP value for the cable category selected. These instruments also allow the user to determine the exact value of the NVP of a specific cable, when testing a cable of known length and calculating the NVP. This process is called “Calibration.”  100% velocidad de la luz en vacio La velocidad de la luz en vacio es 300,000 km/s ó 0.3 m/nsec 01 de abril de 2017 Fluke Corporation - José M. Bonilla

Cálculo de Longitud Ida_y_vuelda_T._de P.  NVP  Velocidad_Luz Longitud = 2 Ejemplo: Si medimos un Tiempo de Propagación: 435 nsec 01 de abril de 2017 Fluke Corporation - José M. Bonilla

Reporte de Longitud Medición de la Longitud del Enlace Calculado por el retardo eléctrico más corto Incluye la longitud de los 2 patch cords Límites de la Prueba (PASS/FAIL) Longitud máxima permitida del enlace MAS 10% de la medición Because the twist rate in each pair of a UTP cable is slightly different, the propagation velocity of the signal is slightly different in each pair. In addition, the difference in rate of twist causes the actual length of the wire pairs to be slightly different as well (with a few percentage points). Therefore, using one value of NVP for a cable produces different “electrical” length values for each pair. So, how long is the cable? These issues coupled with the inherent accuracy limitations of the TDR method prompted the standards team to specify that the shortest propagation delay will be used as the measure of the cable length. Due to all the factors contributing to uncertainty of the length measurement, the limit for PASS/FAIL decisions has been extended to recommended length + 10%. This means that a Channel will not fail until the TDR method produces the answer of 110 m for the shortest pair (propagation delay) in the cable. 01 de abril de 2017 Fluke Corporation - José M. Bonilla

Resultados en los DSPs…
01 de abril de 2017 Fluke Corporation - José M. Bonilla

Tiempo de Propagación 1 2 3 6 1 2 3 6 484 ns 486 ns 4 5 7 8 4 5 7 8 494 ns 481 ns 01 de abril de 2017 Fluke Corporation - José M. Bonilla

Diferencia de Retardo 1 2 3 6 1 2 3 6 3 ns (484 ns) 5 ns (486 ns) 4 5 7 8 4 5 7 8 13 ns (494 ns) 0 ns (481 ns) 01 de abril de 2017 Fluke Corporation - José M. Bonilla

Resultados en los DSPs 01 de abril de 2017 Fluke Corporation - José M. Bonilla

Anomalías de Impedancia
Los DSPs reportan una “anomalía” si: Estos detectan una “reflección significante” Determinada por un valor límite en la configuración Una anomalía es encontrada durante las pruebas de longitud y TDR Una reflección indica un cambio en la impedancia del enlace bajo prueba El equipo reporta la distancia de la anomalía y una Advertencia 01 de abril de 2017 Fluke Corporation - José M. Bonilla

Sistema tradicional de 2 pares
External noise Transmit (Output) Receive (Input) Workstation Transmit (Output) Receive (Input) LAN equipment Signal NEXT This slide shows the traditional ACR as the indicator for signal-to-noise ratio. Consider the Receive Input of the Workstation. The desired signal of the Receive Input is the attenuated signal from the remote end. The undesired signal is the NEXT from its own Transmit Output. On top of the NEXT, there may be externally induced crosstalk. In most situations, this external crosstalk is negligible. The Signal-to-Noise Ratio is the linear ratio of attenuated signal voltage and NEXT voltage. If both quantities are measured in dB’s, the linear ratio corresponds to a subtraction when attenuation and NEXT are expressed in dB. Since both quantities are losses, but normally positive numbers are used to express them, ACR is simply the difference of NEXT and attenuation, when both are expressed in positive numbers in dB. Like was mentioned before, 1000BASE-T implements NEXT cancellation techniques, and there the importance of the ACR figure of merit is reduced. (The same technique was implemented in 100BASE-T2: 100 Mbps on Category 3 cabling, however this standard is not practically used.) Signal 01 de abril de 2017 Fluke Corporation - José M. Bonilla

Atenuación Es la cantidad de señal perdida dentro del enlace de transmisión, expresada en Decibeles (dB) Señal original Señal recibida Attenuation is a very important characteristic of twisted pair cable. To explain this phenomenon to non-technical audiences, you may want to use an analogy from the mechanical world such as “friction”. A bowling ball rolling on a carpeted floor will not reach the same distance as a bowling ball thrown with the same energy on a perfectly polished hardwood floor (or lane). Attenuation is typically measured in decibels (dB) and it characterizes the loss of signal strength along the cable, a smaller value for attenuation (smaller loss) is better. dB perdidos 01 de abril de 2017 Fluke Corporation - José M. Bonilla

Atenuación Fuentes / Causas Las características eléctricas de los materiales del cable y su construcción Pérdidas por inserción debido a terminación inapropiada Reflección debido a desacoplamientos de impedancia Efecto Arriba de cierto nivel de pérdidas, el enlace no transmitirá los datos de la red confiablemente 01 de abril de 2017 Fluke Corporation - José M. Bonilla

Atenuación Medida en decibeles (dB) Decibel es una expresión logarítmica de una relación (voltaje) These dB values are for voltage ratios: 20*log [V_output / V_Input]. From the theoretical point of view, attenuation is always a negative number. Cabling practioners use the absolute values and drop the minus sign. 01 de abril de 2017 Fluke Corporation - José M. Bonilla

Atenuación como una Función de la Frecuencia
The red line represents the limit value per the TIA standard over the frequency range. The blue line represents the measured values of a real channel (wire pair on pins 1and 2) using the DSP-100. 01 de abril de 2017 Fluke Corporation - José M. Bonilla

Resultado de una Prueba de Atenuación
PASS / PASA La atenuación más alta medida y la frecuencia a la que ocurrió Límite de prueba a esta frecuencia FAIL / FALLA The instrument must report, and if desired store, the results of this test by providing the frequency and the measured attenuation value at the worst performance point. If a link exhibits multiple failures, the measurement data corresponding with the failure at the highest frequency must be reported. 01 de abril de 2017 Fluke Corporation - José M. Bonilla

Near End Crosstalk (NEXT)
Transmit Receive El crosstalk la cantidad de señal de interferencia de un par hacia otro NEXT mide el crosstalk del lado de la fuente de la señal (Near End) Los cambios en el NEXT no están relacionados con la temperatura o conductor You may have experienced Near-End Crosstalk or NEXT when you were on the telephone and you could hear a conversation between two “other” people on your line. In computer communication, this is plain devastating. <2nd bullet> This crosstalk occurs along the length of the link. “Near-end” or NEXT is the crosstalk that is measured at the transmitter end. <3rd bullet> NEXT is a critical performance factor that depends on a variety of factors. Not the least of which is the workmanship of terminations; for example, untwisting the pairs more than one half inch can cause crosstalk problems (fail the test). NEXT varies with frequency as we shall see, but it is not influenced by the temperature of the cable or whether it is run through a metallic conduit. 01 de abril de 2017 Fluke Corporation - José M. Bonilla

Efectos del NEXT Similar a la interferencia por ruido La señal “inducida” debe de tener suficiente amplitud para corromper la señal original para ser detectada como datos falsos Efectos: bloqueos intermitentes de la PC falla que afecta a toda la red 01 de abril de 2017 Fluke Corporation - José M. Bonilla

(Par-a-par) NEXT A B C D 6 Combinaciones A  B A  C A D B  C B  D C  D Pair-to-pair in a link with four wire pairs yield six combinations. We will see in a few more slides that the NEXT parameter is to measured from both ends of the link. Therefore, we must make 12 NEXT measurements over many frequency points. Analog testers require a fair amount of time to accomplish this task over a sufficient number of frequency points and with sufficient accuracy (signal settling time). Some testers provide fast test time in trade of with accuracy and the number of frequency points for each wire pair combination. 01 de abril de 2017 Fluke Corporation - José M. Bonilla

NEXT vs Ruido El NEXT y la interferencia por ruido electromagnético son similares Los DSPs son capaces de determinar si hay ruido externo presente Si está presente, los DSPs sacarán un promedio de la interferencia que provoca El ruido externo puede ser identificado con otro equipo (Analizador de Espectros) 01 de abril de 2017 Fluke Corporation - José M. Bonilla

NEXT es medido en dB Extremo Cercano Extremo Lejano 1 2 3 6 1 2 3 6 100 Tx señal Rx dist. When we measure the Near-End Crosstalk of this 100m long Channel from the end on the “left”, the test passes. Let us review what happens in detail at one specific frequency: 62.5 MHz. The attenuation of this channel for this stimulus signal is 10 dB; this is quite acceptable since the limit for Attenuation at 62.5 MHz is 18.5 dB. The crosstalk takes place in the far-end connector. The signal leaking into the “disturbed” pair on pins 3 and 6 must travel back to the instrument end where it is detected and measured. The crosstalk problem at the far end of the channel is measured as 44 dB (10dB attenuation + 24 crosstalk +10 attenuation in the “return path”). The NEXT measurement will most likely be somewhat less because of the contribution of the cable and other connectors along the channel. The limit for the channel at 62.5 MHz is 30.6 dB. Most likely it will pass the NEXT test as measured from the “left-side” end. Potencia de la Distorsión Medida NEXT (dB) = 10 Log Potencia de la Señal Transmitida 01 de abril de 2017 Fluke Corporation - José M. Bonilla

NEXT es medido en dB 01 de abril de 2017 Fluke Corporation - José M. Bonilla

NEXT en Función de Frecuencia
This picture shows the measured “behavior” of NEXT for a good cat 5 link over the full frequency range, from 0.1 MHz to MHz. It also depicts the performance limit according to the TIA TSB-67 (smooth curve on the top). It is important to note the “shape” of the NEXT curve with many sharp peaks. Unless you measure the crosstalk at many points along the frequency axis, you could easily miss one of these peaks that potentially could violate the limit. To come up with an accurate assessment of the NEXT performance of the link, NEXT must be measured at a “sufficient” number of points. Using the analog frequency sweep method, the tendency exists to speed up the test (to gain test time performance) by making fewer measurements along the frequency axis. 01 de abril de 2017 Fluke Corporation - José M. Bonilla

Tiene que ser medido desde ambos extremos del enlace
Medición de NEXT Tiene que ser medido desde ambos extremos del enlace To make matters worse from a test time perspective, the NEXT measurements need to be made from both ends of the link. 01 de abril de 2017 Fluke Corporation - José M. Bonilla

¿Por qué es necesario medir NEXT en ambos extremos?
NEAR END FAR END 1 2 3 6 1 2 3 6 100 Tx PAIR When we measure the Near-End Crosstalk of this 100m long Channel from the end on the “left”, the test passes. Let us review what happens in detail at one specific frequency: 62.5 MHz. The attenuation of this channel for this stimulus signal is 10 dB; this is quite acceptable since the limit for Attenuation at 62.5 MHz is 18.5 dB. The crosstalk takes place in the far-end connector. The signal leaking into the “disturbed” pair on pins 3 and 6 must travel back to the instrument end where it is detected and measured. The crosstalk problem at the far end of the channel is measured as 44 dB (10dB attenuation + 24 crosstalk +10 attenuation in the “return path”). The NEXT measurement will most likely be somewhat less because of the contribution of the cable and other connectors along the channel. The limit for the channel at 62.5 MHz is 30.6 dB. Most likely it will pass the NEXT test as measured from the “left-side” end. Rx PAIR Conector Defectuoso Crosstalk of MHz 01 de abril de 2017 Fluke Corporation - José M. Bonilla

Midiendo desde el Extremo Lejano detectamos la Falla
NEAR END FAR END 1 2 3 6 1 2 3 6 100 Tx PAIR When the NEXT loss is measured form the “other end” of the Channel, the failure is properly detected. Now the NEXT measurement will yield 24 dB at 62.5 MHz. The limit for a category 5 link at this frequency is 30.6 dB. Rx PAIR Concetor Defectuoso Crosstalk of MHz 01 de abril de 2017 Fluke Corporation - José M. Bonilla

Medición de NEXT El TSB-67 define pasos máximos para el muestreo del desempeño de NEXT: (Todos los valores en MHz) The standards prescribes that in the range from 1 MHz to MHz, NEXT needs to be measured at intervals or steps of 150 kHz (or less); and that between and 100 MHz the measurement interval may be increased to 250 kHz. The Fluke DSP-100 analyzes the NEXT performance in the frequency domain in 100 kHz steps across the full range from 1 kHz to 105 MHz --- collecting a total of 1050 data points. The digital test technique allows us to provide this resolution in less than 20 seconds. The highest resolution and accuracy combined with record test speed. 01 de abril de 2017 Fluke Corporation - José M. Bonilla

NEXT- Margen en Peor Caso
Margen: Diferencia entre el valor medido y el valor de pasa/falla (desempeño mínimo) Positivo: Significa que es mejor que el mínimo Negativo: Significa que es menos que el mínimo Peor Caso: El margen más pequeño El punto más cercano a los límites del estándar en todo el rango de frecuencia Puede ser utilizado como una “Calificación del Enlace” 01 de abril de 2017 Fluke Corporation - José M. Bonilla

Evaluación de la medición de NEXT
Frecuencia con la mayor señal de diafonía This slide illustrates that the NEXT value measured at each frequency is to be evaluated against the TIA limit for that frequency and for the type of link selected to determine the PASS/FAIL status of the link. The difference between the limit and the measured value is called the “margin”. (We will express NEXT Loss in positive numbers.) Let’s use the plot in this slide to illustrate the measurement evaluation concept. The limit value for a channel measurement at 55 MHz is 33 dB while the measured value --shown in the plot above -- is 41.5 dB; the NEXT margin, therefore, at this frequency (55 MHz) is 8.5 dB. This evaluation needs to be performed at every frequency at which NEXT is measured. As discussed earlier, the step size should not exceed 150 kHz between 1 MHz and MHz and 250 kHz beyond that frequency. Among all the margin values computed, the tester must report the lowest margin (worst case NEXT) or the frequency and measured value at which the highest value of NEXT has been measured. The latter is the absolute maximum point of the NEXT plot but may not at all be the worst case (closest to the limit). It is likely that the highest NEXT is measured in the upper frequency region. If the link fails NEXT at any point, the worst case NEXT margin must be reported. This margin is a negative number in the DSP-100 because the measured number will be less than the limit value. Example at the same frequency point as illustrated in the slide: the limit is 33 dB. If the measured value is 29.5 dB, the margin is -3.5 dB. Menor valor absoluto en dB - Mayor señal de Crosstalk Típicamente ocurre cerca de los 100 MHz! 01 de abril de 2017 Fluke Corporation - José M. Bonilla

Evaluación de la medición de NEXT
Análisis del Peor Caso This slide illustrates that the NEXT value measured at each frequency is to be evaluated against the TIA limit for that frequency and for the type of link selected to determine the PASS/FAIL status of the link. The difference between the limit and the measured value is called the “margin”. (We will express NEXT Loss in positive numbers.) Let’s use the plot in this slide to illustrate the measurement evaluation concept. The limit value for a channel measurement at 55 MHz is 33 dB while the measured value --shown in the plot above -- is 41.5 dB; the NEXT margin, therefore, at this frequency (55 MHz) is 8.5 dB. This evaluation needs to be performed at every frequency at which NEXT is measured. As discussed earlier, the step size should not exceed 150 kHz between 1 MHz and MHz and 250 kHz beyond that frequency. Among all the margin values computed, the tester must report the lowest margin (worst case NEXT) or the frequency and measured value at which the highest value of NEXT has been measured. The latter is the absolute maximum point of the NEXT plot but may not at all be the worst case (closest to the limit). It is likely that the highest NEXT is measured in the upper frequency region. If the link fails NEXT at any point, the worst case NEXT margin must be reported. This margin is a negative number in the DSP-100 because the measured number will be less than the limit value. Example at the same frequency point as illustrated in the slide: the limit is 33 dB. If the measured value is 29.5 dB, the margin is -3.5 dB. Margen en el Peor Caso: +4.8dB a los 2.7MHz El peor margen no necesariamente ocurre a 100 MHz! 01 de abril de 2017 Fluke Corporation - José M. Bonilla

NEXT Headroom o Paso Libre
Es el peor caso de NEXT de entre las 12 pruebas par-a-par de NEXT 6 combinaciones de pares de la Unidad Principal 6 combinaciones de pares de la Unidad Remota El Paso Libre sirve como calificación del enlace Suficiente = PASA Mientras más grande mejor 01 de abril de 2017 Fluke Corporation - José M. Bonilla

Resultados de Prueba de NEXT
An example of the NEXT plot on the screen of the DSP-100. The vertical line is the cursor which initially is drawn at the frequency with the worst margin (closest to the limit for a passing link, furthest over the limit for a failing link). The cursor may be moved with the left/right arrow keys. The display line under the graph will show the frequency and the NEXT margin measured at that frequency. 01 de abril de 2017 Fluke Corporation - José M. Bonilla

Headroom o Paso Libre Headroom = Caso con el Peor Margen Headroom = 6.5dB 01 de abril de 2017 Fluke Corporation - José M. Bonilla

Resultados de NEXT 01 de abril de 2017 Fluke Corporation - José M. Bonilla

Gráfica de NEXT 01 de abril de 2017 Fluke Corporation - José M. Bonilla

Limites TIA: Atenuación, NEXT, ACR
The respective limit values are shown in this graph. The limit for Attenuation over frequency is the black curve, the limit for NEXT is shown in the purple line while the difference between these two lines (the ACR values) are plotted using the yellow line. 01 de abril de 2017 Fluke Corporation - José M. Bonilla

ACR Attenuation to Crosstalk Ratio Una variante del Signal to Noise Ratio (SNR) Parámetro de desempeño calculado Es la diferencia entre el NEXT (en dB) menos la Atenuación (en dB) Es el “mejor” indicador de desempeño útil para determinar el ancho de banda “usable” para un sistema de dos pares 01 de abril de 2017 Fluke Corporation - José M. Bonilla

Valores Calculados de ACR
The limit line in this graph corresponds to the yellow limit line derived in the previous slide. The purple graph represents the actual values for ACR (calculated from the Attenuation and NEXT measurements at each frequency point). 01 de abril de 2017 Fluke Corporation - José M. Bonilla

Gráfica en un DSP 01 de abril de 2017 Fluke Corporation - José M. Bonilla

Resultados en un DSP 01 de abril de 2017 Fluke Corporation - José M. Bonilla

Channel Performance – NEXT pair-to-pair Cat 5 Cat 6 ACR = 10 dB 69 MHz 147 MHz ACR = 0 dB 115 MHz 221 MHz 10 20 30 40 50 60 70 80 100 150 200 250 Frequency in MHz Attenuation or NEXT loss in dB Category 6 Attenuation Channel NEXTwith cat 6 components Category 5 Attenuation Category 5 NEXT This slide compares the channel performance for Attenuation, NEXT and ACR for a TIA category 5 compliant link using category 5 cabling components (Blue lines) with the predicted channel performance for a Cat 6 channel . Cat 6 channel performance has been calculated based on components specifications per the ISO/IEC September 1997 Document #33. We compare the two systems using ACR as the figure of merit: the frequency where the ACR = 10 dB and the frequency where he ACR = 0 dB; the results for TIA Category 6 or ISO/IEC Class E links are 147 MHz and 221 MHz (200 MHz) respectively. The draft performance requirements for the new ISO/IEC category 6 were set up such that: Cat 5 Pair-to-pair 100 MHz  Cat MHz Cat 6 Power Sum ACR is approx MHz While cable is readily available with much improved performance (which meets the proposed requirements for category 6), improved connecting hardware (=category 6) is much more difficult to obtain. Significant problems related to intermatebility of connecting hardware and test methodology have to be overcome. (See test result samples in next slides) It seems to be prudent to take advantage of improved cable ( that is cat 5e or cat 6) at this time, because the additional cost will likely be minimal, while the improvement in performance is substantial. Better (next generation) connectors can be installed at a later time, if this should become necessary. 01 de abril de 2017 Fluke Corporation - José M. Bonilla

Desempeño de un Enlace El NEXT es utilizado para evaluar la calidad de la mano de obra y de los componentes El ACR es un indicador del máximo ancho de banda utilizable 10 dB: detección de la señal confiable, para Cat-5 0 dB: tanto ruido como señal No se podría diferenciar la señal transmitida del ruido a esa frecuencia We will address link performance in two ways: 1) NEXT as an indicator of the quality of components and workmanship. 2) The ACR as an indicator of maximally usable bandwidth for two wire-pair communication. This can be expressed in a number of ways. We will use: a) The frequency at which a 0 dB worst case ACR occurs b) The frequency at which a 10 dB worst case ACR occurs Depending on the nature of the use of the cabling (other services in the same sheath of LAN systems, which use more than 2 pairs for signal transmission (which includes 1000BASE-T: uses all 4 wire pairs): 1) A worst case ACR based on pair-to-pair NEXT 2) A worst case ACR based on Power Sum NEXT 01 de abril de 2017 Fluke Corporation - José M. Bonilla

NEXT y FEXT Horizontal Cabling Patch Panel Workstation Outlet Hub This diagram clarifies the FEXT measurement function. In case of FEXT one applies the signal at one end of the cable, and one measures what comes out at the other end at an adjacent wire pair. Again, this is an important parameter when using more than 2 wire pairs in a LAN system. Current field testers have the circuitry built in when using a dual-ended NEXT measurement capability. However, it will be necessary to store many more calibration constants (to normalize the receiver in a remote to the amplitude applied by the main unit and vice-versa). As a minimum a software upgrade will be needed. In real life, there is a (statistical) relationship between NEXT and FEXT. Consider a certain amount of coupling between the wire pairs at a certain distance from the beginning. For NEXT, the signal travels to the location where the coupling occurs (and gets attenuated), couples, and then travels back again to the beginning (and is attenuated again). The attenuation of the NEXT signal increases as the distance to the coupling location increases. For FEXT, the signal travels to the location where the coupling occurs (and gets attenuated as before); couples as before, but then travels further towards the end (and incurs additional attenuation). The total attenuation of the FEXT signal is constant (= attenuation of the link). If one performs a dual-ended NEXT test, it is highly unlikely that the FEXT test will fail. NEXT FEXT El FEXT es relativo, todo el crosstalk a lo largo del enlace suma la distorsión de FEXT observada en el receptor 01 de abril de 2017 Fluke Corporation - José M. Bonilla

ELFEXT (Equal Level FEXT)
Horizontal Cabling Workstation Hub Outlet Patch panel attenuation FEXT ELFEXT (signal difference in dB) ELFEXT is simply the FEXT signal relative to the attenuated signal at the remote end of the wire pair with the signal applied to it at the local end. ELFEXT is simply how much the FEXT signal is below the attenuated signal. In linear terms it is a ratio, and therefore when FEXT and attenuation are expressed in dB, the ratio translates into a subtraction: ELFEXT = FEXT - attenuation ELFEXT is like an ACR: ACR = NEXT - attenuation Generally, the requirements related to FEXT will be stated in terms of ELFEXT. At least, this is the current TIA proposal. There will be specifications for both category 3 and category 5 cabling. ELFEXT es la relación entre FEXT y Atenuación 01 de abril de 2017 Fluke Corporation - José M. Bonilla

ELFEXT: Un factor dentro del S/N Ratio
Procedimiento: Medir pérdidas de Far End Crosstalk (“analogo” a la medición de NEXT) Medir Atenuación ELFEXT: Resta de FEXT menos Atenuación en dBs ELFEXT: Un indicador más para aquellos sistemas LAN del S/N donde dos o más señales viajan en la misma dirección Again, ELFEXT is a type of Signal-to-Noise Ratio, as is ACR, but its nature is totally different. ELFEXT is specified in application standards. It involves the measurement of attenuation and FEXT, and computation of ELFEXT. Not discussed in this presentation are the difficulties in measuring ELFEXT. These difficulties relate to the measurement dynamic range of FEXT, and the FEXT from connectors. 01 de abril de 2017 Fluke Corporation - José M. Bonilla

Power Sum NEXT Horizontal Cabling Patch Panel Workstation Outlet Hub This slide shows what power sum NEXT means. For example, consider the 1,2 pair in a 4-pair cable. There is crosstalk from: the 3,6 pair: 1,2-3,6 the 4,5 pair: 1,2-4,5 the 7,8 pair: 1,2-7,8 From the individual pair-to-pair NEXT the Power Sum NEXT is computed. The formula is in ASTM standard D The computation is rather messy, but it can be done. For a 4-pair cable, there are only 4 PS NEXT results compared to 6 P-to-P NEXT results. Given a certain fixed NEXT level, note that it is more difficult to meet a power sum NEXT requirement than a single pair-to-pair NEXT. If all pair-to-pair NEXT are the same (which they normally never are), the power sum NEXT is almost 5 dB tougher to meet than the pair-to-pair NEXT. Of course in 25-pair cabling there are more crosscoupling possibilities. However, depending on the construction of the cable, most of the coupling comes from a few (6) wire pairs. The requirements for PS NEXT in 25 pair cable are the same as for pair-to-pair NEXT 4-pair cat 5. Good PS NEXT properties allow use of different LAN signals running through the same sheath of cable, and will be commonplace. Power Sum NEXT es la combinación de NEXT en un par causado por los otros tres 01 de abril de 2017 Fluke Corporation - José M. Bonilla

Ejemplo de Power Sum NEXT
Ejemplo de Power Sum NEXT sobre un par de un cable de 4 pares 20 30 40 50 60 70 80 90 100 10 Frequency in MHz NEXT loss in dB Limit 1,2-3,6 1,2-4,5 1,2-7,8 PS 1,2 Shown on this graph is a relatively poor performing link. The Power Sum NEXT on pair 1,2 is shown, as well as: The pair-to-pair NEXT 1,2-3,6 and The pair-to-pair NEXT 1,2-4,5 and The pair-to-pair NEXT 1,2-7,8 The standard pair-to-pair NEXT test limit for a TIA category 5 Basic Link. Note that the Power Sum NEXT is essentially the “envelope” of all pair-to-pair NEXT contributions. The Fluke DSP’s implement a patent applied for, extremely fast algorithm (< 0.1 s) to calculate the Power Sum NEXT at every frequency point from the 3 pair-to-pair NEXT values. If the pair-to-pair NEXT components are all equal, than a calculation using the formula for Power Sum NEXT will show that the pair-to-pair NEXT has to be 4.78 dB better than the limit. So, it is a way to provide a meaningful protective margin over the normal category 5 limit. Power Sum FEXT operates in a similar manner. 01 de abril de 2017 Fluke Corporation - José M. Bonilla

Ejemplo: 1000Bese T utiliza los 4 pares
Power Sum ELFEXT Workstation LAN Equipment Signal 1 FEXT Transmit (Output) Receive (Input) This slide shows the impact of crosstalk when more than 1 signal in the cable travels in the same direction. (Only one other wire pair is shown.) Signal 1 travels in the red wire-pair from Workstation to LAN equipment. Another signal 2 travels in the yellow wire-pair, also from the workstation to LAN equipment. Signal 2 couples into the red wire pair along the length of the link, and causes noise in the Receiver of signal 1. (Likewise, Signal 1 couples into the wire-pair of signal 2, not shown in this graph.) Assume that the amplitudes of both transmit outputs is roughly the same. At the Receive Input of the LAN equipment for Signal 1, the desired signal is attenuated output from the workstation on the red wire-pair. The undesired signal is the crosstalk coming from Signal 2 on the yellow wire pair. The total crosstalk measured at the Receive Input for Signal 1 Is called “Far End Crosstalk” (FEXT). The signal-to-noise ratio (SNR) is again the voltage ratio of the two signals, and as for ACR, it both are expressed in positive numbers in dB, this translates into: ELFEXT = FEXT - attenuation. ELFEXT stands for “Equal Level Far End Crosstalk”. The words “Equal Level” are used to indicate that all signals are to be considered with the same level of attenuation. No matter where a crosstalk contribution occurs in the link, it is always attenuated by roughly the same amount. Ejemplo: 1000Bese T utiliza los 4 pares 01 de abril de 2017 Fluke Corporation - José M. Bonilla

PSNEXT and PSFEXT NEXT provocado por fuentes múltiples: “Power Sum” suma los efectos NEXT FEXT provocado por fuentes múltiples: “Power Sum” suma los efectos de FEXT De particular importancia en 2 situaciones: Utilización de cable de 25 pares Aplicaciones de red donde se utilicen dos o más pares para transmitir en paralelo In addition to pair-to-pair NEXT and FEXT there are power sum versions of the same. This is of importance in 2 situations: 1) When using 25-pair cable in horizontal links to carry signals from the wiring/equipment closet (or Floor Distributor in ISO terms) to the work area. In this case, the signals from wire-pairs which are not in the same bundle can couple into the 4-pair bundle associate with one 4-pair link. To provide some allowance for that, the requirement for pair-to-pair NEXT is the same as for the power sum NEXT (a requirement which can be 4.8 dB stricter). 2) In LAN applications where more than 2 pairs are used for transmitting signals (IEEE BASE-T4, IEEE BASE-VG, and expected 1000BASE-T). There are special cases of power sum NEXT, for instance when always 1 pair has traffic in one direction, and other wire pairs can transmit in either direction. In that case power sum coupling to that one pair is important (100BASE-T4). 01 de abril de 2017 Fluke Corporation - José M. Bonilla

Return Loss Medición que refleja la potencia reflejada de la señal dentro del rango de frecuencia de interés Es el resultado de la variación de la Impedancia Característica Variaciones estructurales con consecuencia del fabricante Tipo de conectores Instalación 01 de abril de 2017 Fluke Corporation - José M. Bonilla

Sistemas LAN Full - Duplex
Efecto de Return Loss Sistemas LAN Full - Duplex System A System B Signal A to B Transmit Output Receive Input Receive Input Reflection Signal B to A IEEE 802.3ab intends to use every wire-pair of a standard 4-wire pair connection in a full duplex mode. This means that inside the network interface, the outgoing signal has to be prevented to couple back in the receive input. The circuit that provides this function is called a “directional coupler”. Your standard telephone works conceptually in the same way: while you talk in your telephone, you can hear the party you are talking to. “Echo cancellation” may be used to optimize the performance of the directional coupler. However, reflections which occur in the link, and travel back will be routed into the receiver, and cause an additional noise component, affecting Signal-to-Noise Ratio. Directional Coupler Señal deseada = Señal atenuada en el otro extremo Ruido = Señal reflejada sobre el mismo par 01 de abril de 2017 Fluke Corporation - José M. Bonilla

Return Loss Return Loss de un enlace de 100 mts de acuerdo con TIA Basic Link, comparado con los límites 1000BASE-T 10 20 30 40 50 60 70 80 90 100 Frequency in MHz Return Loss in dB Link Return Loss 1000BASE-T Limit This graphs shows an example of return loss. The frequency response is also somewhat erratic, but not as bad as NEXT Loss. At low frequencies the characteristic impedance of the cable tends to be above the nominal value (thereby causing significant return losses); at high frequencies the characteristic impedance tends to be below the nominal value (also causing significant return losses, variations tend to be more significant, because the wavelength is no longer much longer than the length of the link). In same links, the return loss performance is of real concern. There are no requirements for Return Loss in TSB-67, although it is expected that future versions will include return loss requirements. 01 de abril de 2017 Fluke Corporation - José M. Bonilla

Contribuidores de Ruido Involucrados
ACR es el indicador “tradicional” para sistemas de 2 pares de cables El ACR no será la única medición ELFEXT es otro indicador relevante cuando señales múltiples son transmitidas en paralelo Return Loss es un parámetro importante cuando las señales son transmitidas en paralelo en forma bidireccional (Full-Duplex) In summary, to the traditional ACR as a figure of merit of link performance, you need to add ELFEXT and Return Loss as figures of merit of link performance. ACR is no longer sufficient, although still important. Actually, a more critical parameter is ELFEXT for 1000BASE-T. 01 de abril de 2017 Fluke Corporation - José M. Bonilla

Distorsión combinada con Ruido
Transmit Output Receive Input El receptor debe reconocer la señal atenuada Distorsión en la entrada del receptor: NEXT (3 other pairs) ELFEXT (3 other pairs) Return Loss 01 de abril de 2017 Fluke Corporation - José M. Bonilla

Manejo y Configuración del Equipo
Trabajando con un DSP Manejo y Configuración del Equipo

Autotest Corre todas las pruebas del estándar especificado Evalua los resultados de las pruebas con referencia al estándar seleccionado y determina su calificación The philosophy of operation for the DSP series cable testers is that an autotest is fully “controlled” by the specifications of the selected standard. This standard is selected in the “SET UP” mode. Turn the rotary knob of the test instrument to SET UP and select “Test Standard and Cable Type”. The test parameters and the pass/fail criteria for each parameter are defined in an internal test database. There is no need to select the cable vendor/model when using the DS P Series. What really matters is whether or not an installed link truly meets the desired performance which is defined by either a network standard (e.g. IEEE 802.3u for 100BASE-TX) or a cabling standard (e.g. TIA TSB-67 or IEC/ISO Class D). The selected standard stays in force until the user changes it using the SET UP mode. As long as you are working with the same standard, turn the tester on (AUTOTEST) and press the white Test button to get going. 01 de abril de 2017 Fluke Corporation - José M. Bonilla

Single Test Utilizado para resolver problemas Permite correr cualquier prueba disponible en Autotest, además del HDTDR y HDTDX 01 de abril de 2017 Fluke Corporation - José M. Bonilla

Self Calibration Un DSP debe de ser calibrado con su unidad remota Un DSP-4000 o DSP-4100 puede ser calibrado hasta con 4 unidades remotas diferentes La calibración en campo depende de la carga de trabajo del equipo Para calibrar conecte los DSPs con el módulo de calibración DSP-CAL Remote DSP DSP-Cal 01 de abril de 2017 Fluke Corporation - José M. Bonilla

Self Calibration Encienda el equipo y seleccione Special Functions Vaya a la opción de “Auto Calibración” Presione Test Presione Enter Listo!! 01 de abril de 2017 Fluke Corporation - José M. Bonilla

Special Functions Ver y borrar reportes en memoria Verificar estado de la batería Verificar versiones de Softwar y de estándares Auto prueba Y más!! 01 de abril de 2017 Fluke Corporation - José M. Bonilla

Setup Configure su Analizador de Cable: Estándares de prueba y tipo de cable Fecha y hora Memoria Impresora Autoincremento Y mucho más!! 01 de abril de 2017 Fluke Corporation - José M. Bonilla

Identificación del Informe
Personalice sus reportes de acuerdo a cada uno de sus clientes: Guarde hasta 20 operadores Y hasta 20 lugares The customer can configure a DSP Series tester to minimize the amount of data entry to be performed by the users. If you less than 20 technicians at one site that are regularly using the DSP tester, you can enter all of their names one time. Each technician must then select his/her name before taking the product out to a site. The same is true for customer sites. If your company is working on several projects in parallel, you can enter one time all site names in the testers ( and maintain this list over time). When you head for a specific site, select the correct name before you start the testing. All test reports will include in the header block of information, your company name, the name of the technician who performed the tests, the name of the customer’s site, date and time, the model and serial number of the tester (including the revision of the software), etc. Important to remember, most of this information is automatically included or only needs to be entered either once or only periodically. 01 de abril de 2017 Fluke Corporation - José M. Bonilla

Verificando el Estándar de Prueba
Gire la perilla hasta la opción de Autotest 01 de abril de 2017 Fluke Corporation - José M. Bonilla

Pruebas en Campo con DSPs
Manos a la obra!!

Configuración del Enlace
~90 foot link Patch cord DSP Remote 01 de abril de 2017 Fluke Corporation - José M. Bonilla

Resultados de AutoTest
Autotest corre todas las pruebas del estándar especificado TSB-67: Mapa de cableado Longitud NEXT Atenuación 01 de abril de 2017 Fluke Corporation - José M. Bonilla

Guardando los Reportes
Presione SAVE Introduzca el nombre: Utilice las flechas para seleccionar el carácter Presione Enter Repita el procedimiento hasta completar el nombre y… Presione Save 01 de abril de 2017 Fluke Corporation - José M. Bonilla

Equivalente de NEXT con conectores malos
dB Pass/Fail limit, cat 5 channel Frecuencia en MHz Field Tester Remote 2 m cat 5 15 m cat 5 2 m cat 5 30 m cat 5 2 m cat 5 Link-Under-Test 01 de abril de 2017 Fluke Corporation - José M. Bonilla

Ejemplo de HDTDX con conectores malos
Percent of Full Scale Field Tester Remote 2 m cat 5 15 m 30 m Cable Under Test Distance in meters 01 de abril de 2017 Fluke Corporation - José M. Bonilla

Importancia del Diagnóstico
Los límites de desempeño en el borrador del estándar de Cat-6 para pruebas de ELFEXT y Return Loss están demasiado estrechos Las probabilidades de que un enlace falle son significantes, aun y cuando: Todos los componentes cumplan son sus especificaciones La mano de obra sea de muy alta calidad El Diagnóstico puede ahorrar mucho tiempo y esfuerzo al resolver los “problemas” 01 de abril de 2017 Fluke Corporation - José M. Bonilla

Gráfica de NEXT con cable Cat-3
dB Pass/Fail Limit, cat 5 channel Frecuencia en MHz 2 m cat 5 2 m cat 5 30 m 30 m cat 3 Link-Under-Test Field Tester Remote Gráfica de NEXT con cable Cat-3 01 de abril de 2017 Fluke Corporation - José M. Bonilla

Gráfica de HDTDX con cable Cat-3
Percent of Full Scale Distancia in meters Field Tester Remote 2 m cat 5 30 m cat 5 2 m cat 5 30 m cat 3 2 m cat 5 01 de abril de 2017 Fluke Corporation - José M. Bonilla Link-Under-Test

DSPs Fault Info En este caso se identifico un problema de Pares Divididos o Split Pairs entre los hilos 3,6 y 4,5 Ubicación: Entre los 48 y los 54 pies 01 de abril de 2017 Fluke Corporation - José M. Bonilla

Gráfica de NEXT con Pares Divididos
Field Tester dB Frecuencia en MHz Pass/Fail Limit, cat 5 channel 2 m Cat 5 2 m Cat 5 30 m 3 m Cat 3 Remote 01 de abril de 2017 Link-Under-Test Fluke Corporation - José M. Bonilla

Gráfica de HDTDX para Pares Divididos
Percent of Full Scale Distancia en metros 2 m cat 5 2 m cat 5 30 m 3 m cat 3 Link-Under-Test Field Tester Remote 01 de abril de 2017 Fluke Corporation - José M. Bonilla

Diagnóstico de NEXT en la Serie DSP
The actual display of the TDX Analyzer. The cursor line again is drawn at the highest point in this curve, the point where the crosstalk is most severe along the link. The vertical scale is a qualitative scale. Any point above 50 is very likely a point contributing to the failure of the link. The smaller peaks are connectors along the link. Each 8-pin modular connection or cross-connect is usually visible in the TDX plot. 01 de abril de 2017 Fluke Corporation - José M. Bonilla

Permanent Vs Basic Link 01 de abril de 2017 Fluke Corporation - José M. Bonilla

Diagnósticos - Aislamiento de Fallas
Wire Map failures: The autotest results show (1) that the wire map fails and (2) which wires or wire pairs are open, shorted, or miswired (reversed, transposed, and split pair). If an open or short occurred, the TDR test “locates” the distance of the defect. By the way, it is good to emphasize that the DSP-100 TDR function has NO dead zone. That means that if the defect is in the connector plugged into the DSP-100, the TDR result identifies the distance at exactly 0 feet. Miswires like Reversed and Transposed pairs are reported and depicted in the picture displayed on the screen. In order to properly fix those problems, one should inspect the color codes of the failing wire pairs to avoid making a “right with two wrongs”. Split Pairs can be located with the TDX function. Run TDX and inspect the pair combination that has been accused of being miswired. TDX will show whether the error is in a portion of the link and where the defect starts. Remember, TDX is a unique features of the DSP technology in the DSP-100. Attenuation: Attenuation may fail because you have a poor cable (rather unusual) or because one of the following three reason: (1) An impedance mismatch due to a bad cable segment which causes a partial reflection of the energy and an insufficient signal strength arrives at the end. The TDR test will locate the anomaly if it had not been reported by the impedance test during Autotest (2) A bad contact which may be identified (not necessarily located) by the DC Loop Resistance test. If the resistance is excessively, the connections needs to be inspected. (3) The cable far exceeds the recommended link length. NEXT The unique TDX test will located the defect whether it is a “point defect” (bad connector, poor termination) or a bad link segment. See the following slides. 01 de abril de 2017 Fluke Corporation - José M. Bonilla

¡Conclusiones! Finalmente…

Conclusiones Los estándares para nuevos sistemas de cableado están propuestos Los comités de los estándares han definido Cat-5e y DEFINIRÁN Cat 6 Las especificaciones de los enlaces son más o menos “estables”; es decir, no se han movido Las especificaciones de los componentes TODAVÍA están en desarrollo Los comites definirán nuevas especificaciones de desempeño para los probadores Propuestas para Level IIe y Level III Especs. para precísión en la medición de ELFEXT y RL 01 de abril de 2017 Fluke Corporation - José M. Bonilla

Fluke DSP-4000 y 4100 CableAnalyzer™
Listos para el futuro!! Cumplen con todos los estándares vigentes y propuestos Parámetros de prueba y ancho de banda de 350 MHz Desempeño y precisión superiores Capacidades de prueba únicas Alta exactitud en pruebas de Channel, Basic Link y Permanent Link Diagnóstico sin paralelo Localiza defectos y componentes con desempeño marginal 01 de abril de 2017 Fluke Corporation - José M. Bonilla

Beneficios Operacionales (1)
Legendaria robustez de Fluke Empaque muy fuerte Protección de entradas eléctricas Facilidad de uso Herramientas para identificación de problemas Sensa de tráfico de red en puertos activos Localizador del puerto del Hub Generador de todos Soporta tanto los nuevos como los “viejos” sistemas de cableado 01 de abril de 2017 Fluke Corporation - José M. Bonilla

Beneficios Operacionales (2)
Un día completo de independencia: Batería hasta para 8 horas de trabajo Almacenamiento de reportes interno o en tarjetas de memoria intercambiables Los resultados almacenados no dependen de la batería del equipo Módulos de Comunicación Los operadores se pueden comunicar a través del enlace de prueba de cable par torcido o fibra Software de Administración Gratis!! 01 de abril de 2017 Fluke Corporation - José M. Bonilla

La tecnología digital de Fluke lleva las prue-bas de cable a nuevos niveles… una vez más! Presentando el Fluke DSP-4000/4100 Digital CableAnalyzer El DSP-4000 está construido sobre una plataforma digital que asegura su compatibilidad con los nuevos estándares de prueba y mucho más!! Built upon experience. A new member of a family of high performance instruments. Extending the capabilities to meet the requirements of the foreseeable future. 01 de abril de 2017 Fluke Corporation - José M. Bonilla

¿Preguntas? jbonilla@mexel.com.mx
¡Muchas Gracias! ¿Preguntas?

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