The installation of so-called "dark" (or redundant) fiber is associated with a high degree of risk. The wrong choice of the number and type of fibers to be installed, as well as the poor quality of their installation, can lead to significant financial costs. However, careful preparation for the installation of "dark" fiber will help to avoid this.
Since dark fiber is usually not terminated or tested immediately after installation, the number of quality and low-quality fibers remains unknown until the demand for this fiber arises. This is one of the main difficulties with the use of "dark" fiber. It is necessary to carefully consider and carry out all operations for its installation.
Dark fiber installations are often poorly documented and there is too much unused fiber left in the cables. Therefore, you must first determine the number of fibers to be installed and the types of cables. Next, you should choose the appropriate routes for laying them. You also need to carefully draw up a technological map. The installed cabling system (CS) must be marked and documented.
Determination of the number of fibers
"Dark" fiber is laid with the expectation of network expansion in the future. The installed cabling infrastructure must not only meet the current needs of users in network bandwidth, but also provide the possibility of its expansion. The choice of the number of fibers in the cable (or cables) to be laid is a matter of cost optimization. Future growth in traffic should be estimated and an adequate number of redundant fibers should be considered. In addition, the cable must contain additional redundant fibers in case of failure of those involved.
A good rule of thumb is that there should be one spare pair for every six active pairs of optical fibers on an optical fiber. But be careful, because if you put too many “dark” fibers, then some of them will never be used. If, on the contrary, there are too few of them, then users will soon have to order another expensive cable installation.
The level of fiber redundancy is usually determined based on the importance of the traffic carried over the optical cable. If the customer considers traffic to be very important, then more fibers are required to organize redundant data transmission paths, which, of course, increases the cost of the project. One or another degree of traffic importance has an impact on the choice of configuration of active equipment.
Determination of the type of cables
Choose the type of cables to be installed carefully. In the past, design decisions were usually made by design engineers. Now, due to the complication of these systems, installers are also taking part in this process.
A well-planned CS should take into account all the needs of customers related to the transmission of information over cables. As a rule, the wages of the installers are the main component in the cost structure for the deployment of the CS. Therefore, from the point of view of minimizing it, it is desirable that all types of cables are installed at one time.
Most of the operating COPs are used both for data transmission and for telephone communications. Some enterprises are introducing or planning to implement IP-telephony facilities capable of transmitting traffic over a purely optical cable infrastructure, while others continue to develop traditional telephone systems using copper cable.
Before proceeding with the installation, determine the number of copper cables and optical fibers to be installed. When doing this, consider using hybrid cables with copper conductors and fiber. If a customer's enterprise uses copper wiring to transfer telephone traffic, then instead of the simplest twisted pairs intended for telephony, it is advisable to install a category 5 cable. It will be a backup medium for data transmission in case of damage to the optical cable.
In order to increase the fault tolerance of the CS, stretch copper and optical cables along different routes. If you need to route them between buildings, arrange for them to have different entry points (into buildings).
For more information about: Benefits of Dark Fiber