4 Categorize standard cable types and their properties
There are two kinds of network media cable and wireless. The cable media is referred to as bound media whereas the wireless network media is known as the unbound media. The materials used for constructing cable media are: Metal or Glass or Plastic. The copper cables are used to connect LAN's and WAN's. Cables made of glass or plastic are optical cables and are used for large scale network implementations. The different types of cables that are used are:
Twisted Pair Cable: This is one of the most commonly used network media. The reasons for its dominance are its affordable cost, convenience to work with and versatility. This cable is of two types- Unshielded Twisted Pair (UTP): This is the most common of the twisted pair cable type. It is widely used for computer networks and telephones.
- Shielded Twisted Pair (STP): The characteristic of this cable is that it has an extra shield inside the casing. This shield helps it to deal with attenuation in a better way than UTP and makes it more suitable for distances. The shielding also makes it more expensive option than STP
There are several categories of twisted-pair cable that are used. These categories are:
- Category 1: This is a Voice-grade UTP telephone cable. It is not suited for network applications for it is prone to interference and attenuation. It has low bandwidth capability.
- .Category 2: This type of cable is able to transmit data up to 4Mbps. This is also considered slow for networks and is not used on networks these days.
- Category 3: This type of cable is able to transmit data up to 10Mbps with a possible bandwidth of 16MHz. With the network speeds pushing to 100Mbps these are also not longer effective.
- Category 4: This is a data-grade cable with a throughput of 16Mbps. It is also no longer used.
- Category 5: This type of cable is also a data-grade cable used with Fast Ethernet. It is also not used these days. It can handle 100Mbps with a transmission range of 100 meters.
- Category 5e: This is again a data-grade cable. It is used on networks that run at 10/100 Mbps. If ideally implemented it can run at 1000Mbps. It is suitable for distances up to 100 meters. It provides a minimum of 100MHz of bandwidth.
- Category 6: It is a high-performance UTP cable. It can transmit up to 1 0Gbps and has a minimum of 250MHz of bandwidth. It can transmit at a rate of 10/100/1000Mbps transfer over 100 meters of cable and 10Gbps over shorter distances. It uses longitudinal separator, which is used to keep the four twisted pairs of copper wire in it separate. This allows faster transmission without cross talk.
- Category 6a: It is a later version of Category 6 and offers a minimum of 500MHz of bandwidth. A transmission distance up to 100 meters is specified. It is used with 10Gbps networking standards like 10Gbase-T.
Coaxial Cable: There was a time when the use of coaxial cable was highly prevalent. Many environments still use this type of cable. This cable looks like a television cable and is constructed using an insulation cover, a metal shield and copper wire. The shield and the insulation deal with attenuation, EMI and disturbances like cross talk. These cable types are available with multiple shields also. Coaxial cables are broadly of two types: thin coax and thick coax. Thin coaxial cable is 25 inches in diameter and a maximum length of 185 meters. The length of the cable affects the quality of data signals that are sent. There are different types of thin coaxial cables. They are:
- RG 59/U: This type of coaxial cable is used for low power video connections. It is not suitable for long distances.
- RG 58/U: This type of cable has a solid copper core and is used for radio communications and thin Ethernet (10 Base2)
- RG 58 A/U: This type of cable has a stranded wire core and is also used for radio communications and thin Ethernet (10 Base2)
- RG 58 C/U: This type is cable is used for military specifications.
- RG 6: This type of cable is used for cable television and modems.
The figure below illustrates a thin coaxial cable.
Figure 13: Coaxial Cable
Fiber-Optic Cable: Fiber Optic cables use light unlike the standard networking cables. This characteristic makes them immune to EMI or cross talk. The advantages of this type are:
- It is resistant to chromatic dispersion (signal weakening);
- Data is able to travel over greater distances and at greater speed;
- It is lightweight;
- It is more secure as transmission is taking place in the form of light.
The problems with this form of cable are:
- It is not a cost effective option for small and mid size businesses;
- It is complex to install and requires trained staff and specialized tools to handle it;
- It is not compatible with the existing network infrastructure asking for higher investments for up gradation and replacement of the existing infrastructure.
The figure given below illustrates the components of a fiber optic cable.
Figure 14: Fiber Optic Cable
Types of Optical Fiber: There are two types of optical fibers available:
- Multimode Fiber (MMF): This type has a larger core than the single mode, allowing hundreds of light rays to pass through. Light rays bounce around in the core moving towards their destination, and as a result their speed slows down, potency is reduced and take longer to travel.
- Single Mode Fiber (SMF): This has a smaller core than the MMF and allows light to pass as a beam of light. It transmission abilities are more than the MMF in terms of speed and distance.
Compositions: The internal composition of fiber cables and the size of core can vary.
The common types of fiber-optic cable are:
- 62.5 micron core/125 micron cladding multimode
- 50 micron core/125 micron cladding multimode
- 8.3 micron core/1 25 micron cladding single mode