Design of optical fiber technology and cabling system

1: FDDI / CDDI (fiber / copper distributed data interface)

This is a mature, non-carrier sense, 100M bandwidth sharing network. Uses a token-passing service strategy, network equipment between the main ring and ring linked to the network line or network device fails, there is a strong self-reconfiguration. At the same time, the station management (SMT) is very powerful, suitable for the backbone network. But its high technical difficulty, expensive, poor scalability was the wiring of the ring, not very compatible with ATM.

2: ATM (ATM)

This is based on optical fiber transmission system, the application of statistical multiplexing technology, the use of SMS yuan exchange advanced asynchronous mode. It directly supports data, video, audio and other multimedia transmission. Rate is quite fast (reached 155M, 622M), due to the asynchronous mode, the total efficiency is quite high, more suitable for trunk grid. But it is still a controversial technology, many standards have yet to be improved interoperability between different manufacturers products and versatility to be further improved.

3: FAST ETHERNET (Fast Ethernet)

High-speed Ethernet technology generally include two kinds: the 100M, VG-ANYLAN and the 100M-T. Here mainly on the latter - Fast Switched Ethernet. 100M AG-ANYLAN while providing the multimedia features, but its poor compatibility, high prices, high complexity, there would not be considered. 100BASE-T 10BASE-T modified variant of the original grid divided into several segments, split collision domain, and mining have a buffer exchange and grid transmission rate and transmission efficiency is greatly improved.

Fast Ethernet (compatible with the original Ethernet, software, hardware), advanced (fast - 100MBPS) has practical, easy to upgrade (to the ATM or faster grid to facilitate conversion), scalability (through the Internet connected devices, switches, routers, easy extension), open (hardware and software protocol open), cheap (compared to ATM, FDDI) support manufacturers (supported by Intel, Sun, 3com, Bay, the Accton and other large companiessupport) and other characteristics. Multimedia Grid, Fast Ethernet can well meet the requirements.

Ethernet mesh between the effective distance is shorter (100 m), suitable for a small LAN at the departmental level, but the heart of fiber optic power converter and the fiber can be used to extend the transmission distance.

Fast Ethernet has excellent scalability, the use of switching hubs and hub expansion of the number of users on the grid (being used can be extended), to facilitate future access subnet.

Based on the above analysis, combined with the integrated wiring system and the grid points to provide readers with three structured cabling.

: Twisted pair structured cabling scheme (Fast Ethernet)

This program is the entire wiring system (vertical subsystem, horizontal subsystem, the work area subsystem, equipment, subsystem, wiring subsystem) used in all five twisted pair, network technology is the use of Fast Ethernet technology ( see the design shown in Figure a).

The advantages are: wiring cost is cheap, grid equipment is cheap, easy management, and Fast Ethernet technology is quite mature, its exchange in the second layer, without human intervention.

The drawback is: the higher floors, which may lead to some accommodation of cable length over 100 m, it is well known, according to the principle of wiring, twisted pair generally does not permit more than 100 meters, this will cause signal attenuation as well as distortion.

Second, because all the wiring through the vertical subsystem to the other floors radiation from a central machine room, shaft higher.

Followed by the whole structure of the twisted pair is difficult to upgrade to ATM technology or Gigabit Ethernet, ATM technology and Gigabit Ethernet technology need to use singlemode / multimode fiber to connect to constitute the backbone.

Using a vertical trunk optical fiber, twisted pair for the edge of the wiring scheme (ATM)

The vertical subsystem of such a program using the fiber structure of the other subsystem uses five categories of twisted pair cabling, network technology, ATM technology.

The advantages are: First, the wiring cost is cheaper (the one with the program compared to only slightly higher).

Second, the vertical subsystem is greatly simplified, just radiation optical fiber from the center room to the other floors, each floor (plus the best backup line) distribution of an optical fiber, each floor with five twisted pair cabling, wiring complexity and space complexity are greatly reduced, and 100 m length restrictions no longer exist, because the fiber from the short distance limit (15 km single-mode, multi-mode 1.5-2 km).

Followed by one step, direct the use of advanced ATM switching technology, make the network response speed greatly improved.

Disadvantages: quite expensive network devices and host devices. As a result of advanced ATM switching technology, you must configure the ATM switches, ATM simulation of the bridge, the ATM adapter, these devices are very expensive. ATM switches require special management, based on today's technology, the ATM switching functions can not reach a fully automatic, and set the parameters according to people's work, subject to certain restrictions on management.

Integrated program and the advantages and disadvantages of a third program.

: A vertical trunk optical fiber, twisted pair wiring to the edge program (Fast Ethernet)

That is the program's network of technical and program two wiring. Using optical fiber in the vertical subsystem and other subsystems with five twisted pair. Network technology using fast switched Ethernet.

Advantages: cheap wiring cost; network equipment cost is reasonable; host device requires no special configuration; easy to upgrade. Ethernet switching technology without human intervention. Implement automatic exchange, easy management. And when the need to upgrade to the ATM or Gigabit Ethernet technology, only need to replace network equipment, no need to replace the wiring device, thereby achieving the "wire-once, for life," the goal. But the system need to be upgraded also replace part of the network equipment.

The above three cabling options have their advantages and disadvantages, however, show diagram of the network hardware is equipped with point of view, taking into account the relationship of price and performance and future upgrades and maintenance, I think that the current network technology, select three routing scheme is more reasonable and scientific.