lunes, 22 de noviembre de 2010

Redes Locales (LANs)

Características:
-Baja tasa de error
-Uso de canales de alta velocidad
-Escaso tiempo de propagación de la señal
-Se construyen sobre cable privado
-Fácil de compartir recursos de alta eficiencia
-Comunicaciones cliente servidor (servicio de correo, nombres, fiscos)
-Comunicación distribuida peer to peer
-Simplifica conectividad con otras redes.

Ejemplos
-Ethernet 802.3
-Token Ring 802.5
- Fast Ethernet 802.3
-100 VG: 802.12
-ATM Lan E





IEEE 802


Grupos de Trabajo

Redes Metropolitanas (MANs)

Características:
-Baja tasa de error
-Uso de canales de alta velocidad
-Tiempo de propagación de la señal regular a bajo
-Cable privado o arrendado (utiliza espacios públicos)
-Fácil compartir recursos con alta eficiencia
-Comunicación distribuida (peer to peer) 

Ejemplos:
-FDDI
-DBDB (Con transporte SMDS)
-ATM

Ref: DQDB
-In telecommunication, a distributed-queue dual-bus network (DQDB) is a distributed multi-access[disambiguation needed] networkthat (a) supports integrated communications using a dual bus and distributed queuing, (b) provides access to local or metropolitan area networks, and (c) supports connectionless data transferconnection-oriented data transfer, and isochronous communications, such as voice communications.

IEEE 802.6 is an example of a network providing DQDB access methods.
FDDI
Fiber Distributed Data Interface (FDDI) provides a 100 Mbit/s optical standard for data transmission in a local area network that can extend in range up to 200 kilometers (124 miles). Although FDDI logical topology is a ring-based token network, it does not use the IEEE 802.5 token ring protocol as its basis; instead, its protocol is derived from the IEEE 802.4 token bus timed token protocol. In addition to covering large geographical areas, FDDI local area networks can support thousands of users. As a standard underlying medium it uses optical fiber, although it can use copper cable, in which case it may be refer to as CDDI (Copper Distributed Data Interface). FDDI offers both a Dual-Attached Station (DAS), counter-rotating token ring topology and a Single-Attached Station (SAS), token bus passing ring topology.
FDDI was considered an attractive campus backbone technology in the early to mid 1990s since existing Ethernet networks only offered 10 Mbit/s transfer speeds and Token Ring networks only offered 4 Mbit/s or 16 Mbit/s speeds. Thus it was the preferred choice of that era for a high-speed backbone, but FDDI has since been effectively obsoleted by fast Ethernet which offered the same 100 Mbit/s speeds, but at a much lower cost and, since 1998, by Gigabit Ethernet due to its speed, and even lower cost, and ubiquity.

Redes Extendidas (WANs)

Características:
-Tasa de error dependiente del medio
-Canales de variada velocidad (300 bps a 10 Gbps)
-Tiempo de propagación de la señal dependiente del medio
-Utiliza medios públicos
-Optimiza compartición de recursos entre distintos usuarios

Ejemplos:
-X.25
-Frame Relay
-ISDN
-ATM (Puede ser LAN o MAN)