How to maintain fiber optic cabling

The installation and maintenance of optical fiber cabling, in the cabling system, how to correctly install the very special medium of optical fiber? What problems should be paid attention to during the installation process? At the same time, as a user, what problems exist in the later maintenance? In order to facilitate maintenance, what are the requirements for the early design of the fiber optic cabling system?

Optical fiber, short for optical fiber, consists of thin glass filaments with a diameter of about 0.1 mm. It is transparent and elongated, and although thinner than a human hair, it has a waveguide structure that traps light in it and propagates axially. The wavelength range of light waves currently used for optical communication is in the near-infrared region, and the wavelength range is 0.8-1.8um; it can be divided into short-wavelength bands (0.85um) and long-wavelength bands (1.31um and 1.55um). Optical fiber communication has the following advantages: wide transmission frequency, large communication capacity; low loss; no electromagnetic interference; thin wire diameter, light weight; abundant resources.

There are two main wiring standards popular in the world, one is the North American standard EIA/TIA-568A; the other is the North American standard EIA/TIA-568A. The other is the international standard ISO/IECIS 11801. EIA/TIA-568A and ISO/IECIS 11801 recommend using 62.5/125um multimode optical cables, 50/125um multimode optical cables and 8.3/125um multimode optical cables.

Single-mode fiber and multimode fiber are easily distinguished from the size of the core. The core of single-mode fiber is very small, about 4-10um, and only the main mode is transmitted. In this way, modal dispersion can be completely avoided, so that the transmission frequency band is very wide and the transmission capacity is large. This optical fiber is suitable for high-capacity, long-distance optical fiber communication.

Multimode fiber is divided into multimode abrupt fiber and multimode graded fiber. The former has a larger core diameter and more transmission modes, so the bandwidth is narrower and the transmission capacity is smaller. The transmission capacity is large, and the latter is generally used at present.

fiber optic cabling

1. Fiber selection

The choice of optical fiber depends not only on the number of cores and the type of optical fiber, but also on the environment in which the optical cable is used. For example:

1. If the transmission distance is less than 2km, you can choose multimode fiber. If it exceeds 2km, you can use relay or single-mode fiber.

2. When choosing optical fibers for buildings, attention should be paid to their flame retardant, toxic and smog characteristics. Generally flame-retardant but smoke-free types can be used in ducts or forced ventilation; if in an exposed environment, flame-retardant, non-toxic and smoke-free types should be used.

3. When outdoor optical cables are directly buried, armored optical cables should be selected. For aerial use, fiber optics with a black plastic outer jacket and two or more ribs are available.

Second, the construction of optical fiber wiring

In fiber optic cabling, signal attenuation is also unavoidable. There are two reasons, internal and external: the internal attenuation is related to the fiber material, and the external attenuation is related to the construction and installation, so attention should be paid to:

The first thing that should be done is that the termination and maintenance of the fiber should be performed by a trained technician.

There must be very complete design and construction drawings to facilitate reliable construction and future inspections. During construction, pay attention to the optical cable not to be heavily pressed or crushed by hard objects; in addition, the traction force should not exceed the maximum laying tension.

When turning the optical fiber, the turning radius should be greater than 20 times the diameter of the optical fiber itself.

When the optical fiber passes through the wall or floor, a protective plastic tube with a guard should be added, and the tube should be filled with flame-retardant filler. It is also possible to pre-lay a certain number of plastic pipes in the building.

The length of one laying should not be too long (generally 2KM). When wiring, pull from the middle to both sides.

When optical fibers are used in the backbone network, at least 6-core optical cables should be used in each wiring room, and 12-core optical cables should be used for advanced applications. This is considered from three aspects: application, backup and expansion.

The most important thing for long-distance optical fiber laying is to choose a suitable path. The shortest path is not necessarily the best, also pay attention to land tenure, the possibility of erection or burial, etc.

When laying in mountainous areas and areas with high-voltage power grids, attention should be paid to the reliable grounding of metal objects in optical fibers. Generally, there should be 3 grounding points per kilometer, or use non-metallic optical fibers.

The methods mainly include permanent connection, emergency connection and active connection.

Data center cabling system planning methods and comparison

To plan the cabling system, you must first understand the data center environment of the equipment that needs to be connected in the cabling system. Although financial enterprises have different business platforms, regardless of whether they adopt a closed system or an open system, the active IT equipment connected to their data centers mainly includes core servers (mainframes or high-end minicomputers), peripheral application servers (low-end-end minicomputers, PC server), storage, peripherals (tape drives, libraries, printers), communications (routers, switches), etc.

The interfaces of these devices are mainly optical fibers, and there are also electrical ports (mainly distributed on PC servers). There are many types of device interface channels in the host environment, including ESCON with a half-duplex transmission rate of 17MB/s, FICON, MTRJ, SC, LC, ST, etc. with a full-duplex transmission rate of 100MB/s.; mode and multi-mode. In the minicomputer environment, the device interface types are relatively simple, mainly LC and SC, but the devices are scattered.

The easiest way to connect the above devices is to connect them directly. That is, the optical fiber interfaces on different devices are directly connected through double-core optical jumpers, and the interconnection between various interface types is completed through connectors at both ends, such as: ESCON duplex-ESCON duplex, SC-LC, LC-LC, etc. in small In fiber optic cabling systems, direct connection is the most cost-effective way to plan. But that changes for large data centers with hundreds or even thousands of Fiber Channel connections.

In terms of maintenance, imagine hundreds of twin-core fibers crossing each other under a raised floor. This makes computer room management, equipment update and expansion more and more difficult. When the data center computer room needs to replace or add equipment, various optical fibers under the raised floor make it very difficult and complicated to replace old optical fibers and lay new optical fibers. One move affects the whole body, and a little carelessness will cause unexpected problems in the entire system.

Therefore, a more reasonable data center cabling system planning method should be to adopt a structured architecture, use backbone optical fibers and wiring cabinets, and reduce under-floor operations. Although the connection points are increased, the system architecture is more reasonable and the maintenance and management are more convenient.