Elements of the structured cabling - MS Elektro Olomouc
The structured cabling consists of the following components:
a) active routers, switches
b) passive cables, interconnecting panels, distribution boxes
The router task is to ensure connection between the local network (LAN) and the exterior network, primarily to the Internet. The router may also provide for interconnection between several networks, e.g. within one company. The function usually fulfilled by the router within the network is called “GATE”.
Switch is an active network element that interconnects individual network segments. The switch comprises few or more ports (up to several hundred), to which the network devices or network parts are connected. The term “switch” is used for various devices in a number of network technologies.
- It allows parallel communication between various ports (i.e. pairs of ports 2-3, 5-9, 6-4, … may communicate simultaneously).
- It allows application of high-speed ports, and by means of the intelligent buffering it can divide the operation of the high-speed port among several ports with lower speed.
- Apart from the standard half duplex operation, it brings forth a full duplex operation that is theoretically twice as fast.
– is a relatively new type of device working at the speeds that are usual for the second layer and the third layer information, it provides for proper routing at the switching speed – it replaces the slow routers in the section of the broadcast domains; as a result, the common routers are increasingly used for connecting different technologies.
networks using the twisted pair (TP) started at a speed of 10Mbps
(10BASE-T). Although the value of 10 Mbps looks as sufficient (primarily due to the “mega-” prefix), the throughput that theoretically achieves 1.25 MB/sec is not sufficient anymore. The fact that this transmission band is shared by several computers in the network makes all things worse. The unshielded cable of Cat. 3 - UTP is sufficient to interconnect the device.
The present standard is represented by the 100Mbps
100BASE-TX elements. The advantage is a higher theoretical throughput (12.5 MB/sec), reverse compatibility and ability to adapt to the network environment. 100BASE-TX commonly uses the Cat. 5 cabling. These cables are formed by four pairs of stranded conductors. Each pair has its colour identification code. Pairs are distinguished by colours. Stranding or twisting ensures higher resistance to the ambient interferences.
twisted twin cable
• Also known as “twisted pair”
• Able to transfer data at a baud rate of 100 Mb/s
• Two wires (conductors) are always twisted around each other - minimising the crosstalk, electromagnetic interference and loss due to the capacitance.
• Produced in two basic variants :
- Unshielded Twisted Pair
For higher demands and interconnection of several segments within the network, it is nowadays possible to use 1000BASE-T also known as Gigabit Ethernet
. This network also uses the twisted pairs for transmissions - cables must at least comply with the requirements for Cat. 5, however the “enhanced” Cat5e
variant is recommended.
for illustration, the following are cables of various categories:
cables for various categories (Cat.5, 5e, 6, 6a and 7) differ from each other by various cross-sections of their wires (conductors).
Works in the band width of up to 100 MHz. Cable lines for the computer network, with a baud rate of 100 Mbit/sec, or 1 Gbit/sec if all 8 threads are used - not used anymore
Works also in the band width of up to 100 MHz, but is more accurate in certain respects. Due to its affordability, the Category 5e is nowadays the most widely used category of the structured cabling system.