According to the IBDN standard, it is generally recommended to use 12 cores for each communication room in a building, and 24 cores between buildings.
It can be considered as follows:
First clearly know the number of wiring points on that layer, figure out the number of switches, whether the connection between switches is stacked or not, if stacked, 6 cores are enough if the core switches are dual hot standby redundant (2 cores each with 2 cores and 2 cores redundant).
If not stacked, a switch to 4 cores, how many switches multiplied by 4 plus 4 cores of redundancy, will be sufficient.
Empirical approach: each floor wiring room (horizontal wiring closet), set up a fiber.
Generally six-core: two-core use, two-core backup, two-core redundancy; there are also the use of eight-core fiber.
Terminology Remarks:
redundancy: as long as there is more than used, the extra is called redundancy;
primary backup: one used and another identical one as a backup;
Hot backup: both are in working condition at the same time
Cold backup: the backup device is in standby state
1, in general there are several terminals need a few cores, but the actual program design and construction will consider redundancy, so more than two cores per terminal, into the cost can also be used throughout the line redundancy 1-2 cores, for example, you have three fiber optic access switch, you need to have three cores (actually to use four-core fiber optic cable), because in addition to a core of fiber, there is basically no single number of cores of fiber optic cable, such as: three-core, five-core, etc., of course, not absolutely, Five cores, of course, is not absolutely a core can only be connected to a terminal device, but also in a core in series with more than one terminal, but this requires multiple fusion, light attenuation is larger, can not achieve long-distance transmission.
2, single-mode and multimode problem: multimode is actually a core can transmit multiple data at the same time, while single-mode can only transmit one way data, so the quality of single-mode transmission and distance are better than multimode, so single-mode more for longer distance outdoor transmission.
3, first look at a few systems are using fiber. For example, a certain optical node, the application system has a network, monitoring. Among them, the network only needs a route, need to occupy two cores of fiber; monitoring has 4-channel image, need to install a 4-way video optical transceiver, need to occupy a core of fiber. Then from the server room to the optical node requires a total of 3 cores of fiber, fiber optic cable design from the server room to the optical node for 6 cores of fiber optic cable, of which 3 cores for redundancy. From the cost consideration, build a single-mode fiber optic cable. The actual is should pull a 6-core single-mode optical cable to the optical node.
