Transmission Media Are Essential For Allowing Devices In The Broad World Of Computer Networks To Exchange Data With One Another. Transmission Media Include A Broad Spectrum Of Media And Technologies, Ranging From Modern Wireless Technology To Traditional Cable Connections. This Comprehensive Book Covers All The Necessary Knowledge As It Examines The Various Kinds, Characteristics, And Applications Of Transmission Media In Computer Networks.
Overview Of Transmission Media
Physical Channels Called Transmission Media Are What Let Data Move Back And Forth Between Computers In A Network. They Are Also Known As Communication Mediums Or Channels At Times. These Media Serve As Conduits For The Optical, Electromagnetic, Or Electrical Impulses That Are Used To Transport Digital Data Between Different Locations.
Different Transmission Media Types
In Computer Networks, There Are Two Main Types Of Transmission Media: Guided Media And Unguided Media. Let’s Examine Each Kind In Greater Detail:
Guided Media:
• Often Called Confined Or Wired Media, Guided Media Are Tangible Media That Offer A Concrete Means Of Signal Transmission. Among The Guided Media Examples Are:
• Twisted Pair Cable: To Reduce Electromagnetic Interference (EMI), Pairs Of Insulated
Copper Wires Are Twisted Together To Create Twisted Pair Cables.
• They Are Widely Used For Ethernet Connections In Local Area Networks (Lans).
Coaxial Cable:
• Coaxial Cables Have An Exterior Insulating Layer, A Metallic Shield, And A Dielectric Insulator Encircling The Inner Conductor.
• Two Typical Uses For Them Are Cable Television (CATV) And Broadband Internet Connections.
Optical Fiber:
• Data Can Be Sent As Light Pulses Via Optical Fibers, Which Are Composed Of Glass Or Plastic Strands.
• They Are Ideal For High-Speed Internet Connections And Long-Distance Phone Lines Because They Possess A Broad Bandwidth, Resistance To Electromagnetic Interference, And Long-Distance Data Transmission Capabilities.
Unguided Media:
• Unguided Media, Sometimes Referred To As Unbounded Or Wireless Media, Carry Signals Without The Use Of Physical Channels. Rather, They Spread Electromagnetic Waves Via A Vacuum Or The Air.
Unguided Media Examples Include:
What is Transmission Media in Computer Network?
Transmission media is a communication channel that transmits information from the source/transmitter to the receiver. It is a physical path for data transfer through electromagnetic signals. Information is carried over in the form of bits through LAN. It can mediate the propagation of signals for telecommunication. Signals are imposed on a wave that is suitable for the chosen medium. These media lie underneath the physical layer that regulates them. While designing a transmission, it is important to keep the following pointers in mind:
What are the Types of Transmission Media in Computer Networks?
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If you are wondering how many types of transmission media are there, then do take a look at this section. Broadly, there are two types of transmission media in computer networks including guided and unguided media. These two types of transmission medium in computer networks have further subtypes. Let us discuss these in detail.
Guided Transmission Media
Guided media are also known as wired or bounded media. These media consist of wires through which the data is transferred. Guided media is a physical link between transmitter and recipient devices. Signals are directed in a narrow pathway using physical links. These media types are used for shorter distances since physical limitation limits the signal that flows through these transmission media.
Twisted Pair Cable
In this type of transmission media, two insulated conductors of a single circuit are twisted together to improve electromagnetic compatibility. These are the most widely used transmission medium cables. These are packed together in protective sheaths. They reduce electromagnetic radiation from pairs and crosstalk between the neighbouring pair. Overall, it improves the rejection of external electromagnetic interference. These are further subdivided into unshielded and shielded twisted pair cables.
Unshielded Twisted Pair Cable(UTP): These consist of two insulated copper wires that are coiled around one another. These types of transmission media block interference without depending on any physical shield. The unshielded twisted pair are very affordable and are simple to set up. These provide a high-speed link.
Shielded Twisted Pair (STP): This twisted cable consisted of a foil shield to block external interference. The insulation within these types of twisted cable allow greater data transmission rate. These are used in fast-data-rate Ethernet and in data and voice channels of telephone lines.
Optical Fibre Cable
Also known as fiber optic cable, these are thin strands of glass that guide light along their length. These contain multiple optical fibers and are very often used for long-distance communications. Compared to other materials, these cables can carry huge amounts of data and run for miles without using signal repeaters. Due to lesser requirements, they have less maintenance costs and it improves the reliability of the communication system. These can be unidirectional as well as bidirectional in nature.
Coaxial cable
These guided transmission media contain an insulation layer that transmits information in baseband mode and broadband mode. Coaxial cables are made of PVC/Teflon and two parallel conductors that are separately insulated. Such cables carry high frequency electrical signals without any big loss. The dimension of cable and connectors are controlled to give them constant conductor spacing for efficient functioning as a transmission line.
Hardline Coaxial Cable: These are used for high signal strength applications including long-distance telephone lines. These look like any regular coaxial cable but these are 1.75″ thick. This type of cable has the capability to carry hundreds of channels of cable tv. Such cables have sufficient interent capacity for medium sized office building.
RG-6 Coaxial Cable: This is mainly used for cable and satellite signal transmission for the purpose of residential and commercial installation. These are thin and are easily bendable for wall or ceiling installation. Such cables are preferred for relaying cable television signals.
Triaxial Cable: Also known as triax, these are the electrical cable that come with an add on layer of insylation and second conducting sheat. These cables provide greater bandwidth as well as rejection of interference as compared to coax. However, triaxal cable are expensive type of transmission media.
Stripline
This is a transverse electromagnetic (TEM) transmission media that is built on the inner layers of multi-layer printed circuit boards. These are used in high or low-level RF signals that require isolation from surrounding circuitry. It is a type of printed circuit transmission line in which a signal trace is sandwiched between the upper and lower ground place. Stripline minimizes emissions electromagnetic radiation is completely enclosed within homogeneous dielectric. Along with the reduced emissions, it also shields against incoming spurious signals.
Microstripline
While Microstripline is simiar to stripline, it is not sandwiched and are present above the ground plane. These can be fabricated with any technology where the conductor is separated from the ground plane by a dielectric layer called subtrated. These transmission media convert microwave frequency signals. Microstrip is also used for building microwave components such as couplers, filters, power dividers, antennas, etc. In comparison with the traditional waveguide technology, it is less expensive.
2. Unguided Transmission Media
Also known as unbounded or wireless media, they help in transmitting electromagnetic signals without using a physical medium. Here, air is the medium. There is no physical connectivity between transmitter and receiver. These types of transmission media are used for longer distances however they are less secure than guided media. There are three main types of wireless transmission media.
Radio Waves
Radio waves are transmitted in every direction throughout free space. Since these are omnidirectional, sent waves can be received by any antenna. These waves are useful when the data is to multicasted from one sender to multiple receivers. Radio waves can cover large areas and even penetrate obstacles such as buildings and walls. The frequency of these waves ranges between 3 kHz to 1GHz. Due to its omnidirectional nature, issues such as interference might arise when another signal with the same bandwidth or frequency is sent.
Infrared
These waves are useful for only very short distance communication. Unlike radio waves, they do not have the ability to penetrate barriers. Their range varies between 300GHz – 400THz. Since they have larger bandwidth, the data rate is very high for infrared waves. These have less interference and are more secure.
Microwaves
For these waves, it is important for the transmitter and receiver antenna to be aligned. This is why it is known as line-of-sight transmission. Due to this, they are suitable for shorter distances. They comprise of electromagnetic waves with frequencies ranging between 1-400 GHz. Microwaves provide bandwidth between the range of 1 to 10 Mbps. Distance covered by the signal is proportional to the height of the antenna. For travelling to longer distances, the height of the tower should be increased. These are further sub categorized as terrestrial and satellite type microwave transmission.
Terrestrial type microwave transmission: In this type, high directional antennas are used for line of sight propagation paths that use frequency between 4-12 GHz. These are parabolic antennas having diameters that range from 12 inches to feet depending on their spacing.
Satellite type microwave transmission: Signals are transmitted to those spaces where satellites are positioned and they retransmit the signal to appropriate locations. Since they only receive and retransmit the signal, they act as repeaters. It is a much more flexible and reliable method of communication in comparison with cables and fiber systems.
Pros and Cons of Transmission Media in Computer Networks
The following table summarises the advantages and disadvantages of transmission media:
| Type | Advantages | Disadvantages |
| Unshielded Twisted Pair | Less expensive, Easy to install, High speed |
Attenuation leads to short-distance communication, Susceptible to external interference |
| Shielded Twisted Pair | Reduced crosstalk, Faster than UTP |
Bulky and expensive, Difficult to install |
| Optical Fibre Cable | Increased bandwidth, Immunity to interference |
High-cost, Fragile |
| Coaxial Cable | High bandwidth, Noise immunity |
Complete disruption due to single cable failure |
| Stripline | Better isolation, Less loss of radiation |
Complex troubleshooting, Expensive |
| Microstripline | Easy interconnection and adjustments, Major fabrication advantage over stripline due to its open structure |
Only for a short distance |
| Radio | Easy to generate, Can penetrate obstacles |
More interference |
| Infrared | Less interference | Cannot penetrate obstacles |
Considerable Factors While Designing Transmission Media
While designing transmission medium in computer networks, it is important to consider the following factors:
- Greater bandwidth of the transmission medium allows higher data transmission rate of signal.
- Due to transmission impairment, the received signal may get destroyed since it does not seem identical to the transmitted signal.
Applications of Transmission Media in Computer Networks
| Type | Uses |
| Unshielded Twisted Pair | Telephonic applications |
| Shielded Twisted Pair | Fast data rate ethernet |
| Optical Fibre Cable | For transferring large volume of data |
| Coaxial Cable | Cable TVs, Analog TV |
| Stripline | Solid-state microwave systems |
| Microstripline | Solid-state microwave systems |
| Radio | Cordless phones, AM/FM radios |
| Infrared | Wireless mouse, printers, keyboards |
| Microwave | Mobile phones, televisions |
Radio Waves:
• Electromagnetic Waves With Frequencies Varying From Hundreds Of Gigahertz To A Few Kilohertz Are Known As Radio Waves.
• They Are Used In Bluetooth, Wi-Fi, And Cellular Networks, Among Other Wireless Communication Technologies.
• Microwaves: Microwaves Are Used In Microwave Ovens, Satellite Communication, And Point-To-Point Communication Systems. Their Frequencies Range From 1 To 300 Gigahertz.
• Infrared Waves: Used In Applications Such As Distant Sensing, Infrared Waves Have Frequencies That Are Marginally Lower Than Visible Light Proximity Sensors, Infrared Data Transfer, And Controls.
Features Of Media Transmission
• Different Properties Of Transmission Media Influence Which Applications And Network Environments They Are Appropriate For. Let’s Examine A Few Essential Qualities:
Bandwidth:
• Measured In Bits Per Second (Bps) Or Hertz (Hz), Bandwidth Is The Maximum Data Transfer Rate Of A Transmission Medium.
• Higher Bandwidth Enables Faster Data Transmission, Which Allows For The Transfer Of Larger Volumes Of Data In Less Time.
Transmission Speed:
• The Pace At Which Data May Be Sent Over A Medium Is Indicated By Transmission Speed, Which Is Often Referred To As Data Rate Or Throughput.
• It Is Impacted By Factors Such As The Medium’s Bandwidth, Signal Encoding Techniques, And Network Protocols.
Distance Of Transmission:
The Maximum Distance That Data May Be Reliably Sent Across A Medium Without Experiencing A Substantial Loss In Signal Strength Or Degradation Is Referred To As The Transmission Distance. Factors Like As Signal Attenuation, Interference, And Amplification Affect The Transmission Distance.
Security:
Security Includes Safeguards Against Unwanted Access, Interception, And Manipulation Of Data That Is Being Transferred. Wired Media, Such As Optical Fibers, Have Inherent Security Benefits Due To Their Physical Separation, But Additional Encryption And Authentication Steps Are Required For Wireless Media To Ensure Secure Data Transport.
Reliability:
The Consistency And Dependability Of Data Transfer Across A Medium Are Referred To As Reliability. Variables Including Signal Attenuation, Electromagnetic Interference, And Susceptibility To Environmental Conditions Might Affect How Reliable Transmission Media Are.
Applications Of Transmission Media
There Are Numerous Uses For Transmission Media Different Industries, Including Local Area Networks (Lans And Wans), Multimedia Streaming, And Telephony. Let’s Look At A Few Common Applications:
Local Area Networks, Or Lans:
• When LAN Installations Are Used To Connect Devices Within A Constrained Geographic Area, Such As A Campus Or Office Building, Twisted Pair Cables And Optical Fibers Are Commonly Utilized.
• Ethernet And Wi-Fi Technologies Facilitate File Sharing, Printing, And Internet Access, Among Other Activities, Making Data Transfer Via These Mediums Easier.
Wans, Or Wide Area Networks:
• Wans Use Transmission Media Such Satellite Links, Leased Lines, And Optical Fiber Networks Or Institutions To Link Geographically Far Places.
• Data Transmission Over Long Distances Is Made Possible By These Media, Which Makes Services Like Cloud Computing, Virtual Private Networking (VPN), And Internet Access Is Feasible.
Communication:
• This Industry’s Communication Networks Are Built On Transmission Media Such As Optical Fibers And Microwave Links.
• Among The Speech, Data, And Video Transmission Services That Are Provided By These Mediums Are Video Conferences, Television Broadcasts, And Phone Calls.
Streaming Of Multimedia:
• In Order To Transport Music, Video, And Other Multimedia Content Via The Internet, Transmission Media Are Necessary. High-Bandwidth Media, Such As Cable Connections And Optical Fibers, Enable Users To Enjoy Seamless Streaming Experiences For On-Demand Entertainment, Live Events, And Video Conferencing Services.
To Sum Up
Transmission Media Are Essential To Computer Networks Because They Allow Data To Flow Easily Between Devices In A Variety Of Scenarios And Applications. Transmission Media, Including Unguided Ones Like Microwaves And Radio Waves) Or Directed (Such As Optical Fibers And Twisted Pair Cables) That Support Global Population Digital Connectivity And Modern Communication Technologies. With A Deep Understanding Of The Types, Characteristics, And Applications Of Transmission Media, Network Specialists Can Design Dependable And Efficient Communication Infrastructures To Meet The Evolving Demands Of The Digital Age.