Any medium by which data transfer without any physical device like cable can be called as wireless transmission medium. Example can be wireless phone and wireless connection in laptops.

Wireless Mediums can be off following type

Radio Frequency:à

1)      Speed of radio frequency can be 1 to 10Mbps.

2)      Radio frequency can cover distance of 70 Meters to 1 Km.

3)      Frequency Range of Radio Frequency is 10KHz to 1000 MHz

4)      In Radio frequency single Range frequency is not secured but spread spectrum can be secured.

5)      Can affect from interference of other radio frequencies as well as other electrical signals.

Infrared:à

1)      Speed of Infrared can be 10Mbps to 100Mbps.

2)      Maximum distance covered by infrared is 100Meters.

3)      Working frequency of Infrared is 1000Ghz to 400THz.

4)      Good in security as no electrical signal pass is there.

5)      Effect of environmental condition is very high in Infrared signals. It need to maintain line of sight for data transfer.

Microwave:à

1)      Speed of Microwave is 1 to 10Mbps.

2)      Distance covered by Microwave can be 1 Mile to global reach.

3)      Working frequency of Microware is 1000MHz to 1000GHz.

4)      If signals are encrypted microwave transmission is secured.

5)      Effect of interference is less comparison to Radio Frequency.

In looks we can say fiber optic cable looks similar to coaxial cable as it has one central cable and one shield and then one more shield but in this cable data transfer goes using optical transmission.

Fiber Optic cable

In fiber optics cable there is one central core made up of best glass material best possible refraction, this core is covered by another glass material that has lower refraction rate to keep light inside of core. This second layer is covered by a plastic jacket.

Fiber Optic Cable

Fiber optic sheath: àFiber sheaths are laid in ground and in oceans for creating a long distance network. Fiber sheath are group of multiple fiber optic cables as a single wire. We can understand it easily by example of a flexible copper wire. If you have ever removed (I am sure you have done it) plastic covering of flexible copper wire you can see multiple thin wires inside it and all these wire makes a thick wire to sustain for heavy electric load. Similarly a fiber optic sheath is made up of multiple fiber optics cable in one jacket.

Fiber Optic Sheath Virtual diagram

 Characteristics of fiber optics cable

1)      Maximum cable length of fiber optic cable can go from 2KM to 100KM.

2)      Bandwidth of fiber optic cable can go 100Mbps to 1Gbps.

3)      Connector types for fiber optic cable are ST, SMA, SC, and MIC.

4)      Fiber optics cable is most expensive transmission media in all of network mediums.

5)      Interference protection in fiber optics cable is best

Benefit of Fiber optics cable

1)      Fiber optics cable can be installed over long distance.

2)      Fiber optics cable provide large amount of bandwidth.

3)      Fiber optics cable is free from EMI and RFI.

4)      Fiber optics cable cannot be easily taped so it’s very secure in comparison to all other cables.

Drawback of problem with Fiber optics cable

1)      Most expensive media for purchase and installation.

2)      Rigorous guideline to install and configure.

3)      Take lot of time to repair if broken.

Next chapter is Wireless that is last chapter in transmission medium.

Twisted pair cable is a cable in which pairs of wires are twisted around each other to minimize interference from other twisted pairs. Twisted pair cable can be shielded or unshielded (most common). Twisted pair cables are generally not costly and it’s easy to install.

Twisted pair cables are rated by different category. In twisted pair cable highest category is category 7 cable while lowest category is category 1 cable.

Here is a short description of each category of twisted pair cable and there common uses.

Category 1 Twisted pair cable: àCategory 1 twisted pair cable is 2 pairs cable, it’s a voice grade cable and use for telecoms but not for data.

Category 2 Twisted pair cable:à  Category 2 twisted pair cable is 2 pair cable, data can be transfer on this with maximum of 4Mbps speed but now a day’s it’s not recognized and no one use it.

Category 3 Twisted pair cable:à Category 3 twisted pair cable is 4 pair cable on which data can be transfer with maximum of 10Mbps. Category 3 cable is used for 10BASE-T network and for voice communication.

Category 4 Twisted pair cable:à Category 4 twisted pair cable is 4pairs cable in which data can be transfer with maximum of 16mbps speed. This cable is used for IBM token ring network.

Category 5 Twisted pair cable: àCategory 5 twisted pair cable is 4 pairs cable in which data can be transfer with 100Mbps+ speed. It use for 100BASE-x and Ethernet network. Presently most of the networks are running with this cable.

Category 5e twisted pair cable:àIn Category 5e twisted pair cable e stand for enhanced. This cable can carry data up to 1000Mbps with 100MHz signal frequency. Rests of the specification are same as Category 5 cable.

Category 6 Twisted pair cable:à it’s a 4 pair cable that provides improved performance as compare to category 5e cable. In category 6 twisted pair cable data transfer at 1000Mbps speed with 250MHz signal frequency.

Category 7 twisted pair cable: àIt’s a 4 pair cable with completely shielded twisted pair and it works at 600MHz frequency at 1000Mbps speed. Here completely shielded means each pair is shielded inside outer shield or covering.

Difference between shielded and unshielded twisted pair cable

Unshielded twisted pair cable(UTP)

1)      Ordinary telephone wire or similar to that.

2)      Cheapest in term of price.

3)      Easiest to install.

4)      UTP suffer from external or internal interference.

5)      Not as secure as STP(shielded twisted pair cable) in terms of physical damage.

Unshileded twisted pair cable

Shielded twisted pair cable (STP)

1)      Metal braid or sheeting reduce inference

2)      More expensive comparison to UTP cable.

3)      Harder to handle as it’s very thick and heavy.

4)      Secure in terms of physical damage due to extra shields on internal pair.

Shileded Twisted pair Cable

Weather its shielded twisted pair cable or unshielded twisted pair cable Maximum length of UTP and STP cable is 100 meters. Both connect using RJ 45 connector and both the cable work in Baseband signal transmission mode with impedance of 50 ohm

Next chapter is fiber optics cable

Cable is the medium through which information usually moves from one network device to another device. Network cable is guided medium in transmission media.  There are different types of network cable which are commonly used in LANs. Which kind of cable we are choosing is dependent on network topology, size of network and network protocol.

To create a success full network it’s very important to understand character stick of different type of cable and how they are different from each other. What are the limitation with them, what could be maximum size of any particular type of cable and all other aspects?

Following are the characteristics of cables for making a good network

Segment and segment length:à A single network wire that connects one network device with another network device is called segment and length of this segment is called segment length.

Attenuation:à Attenuation is general term that refers to any reduction in strength of signals. Attenuation may occur with any type of signal weather it’s digital or analog. Some time it called loss, attenuation is natural consequence of signal transmission over long distance.

Bandwidth:à Bandwidth is generally use as synonym of data transfer rate. The amount of data that can be carried from one point to another point in given time period (generally one second) is known as bandwidth of medium.

Here one thing I must clear you that if its 100Mbps LAN than it doesn’t means your 100 MB data will copy from one location to another location in 1 second.  Here LAN speed is 100Mbps (megabit per second) and data size is 100 MB (megabyte) so multiply by 8 in your speed for calculating data transfer time in MB. I will explain about bit byte and other terms in other chapter.

Number of segment:à It defines Maximum number of segment in a network, how many segments can be there in one network for smooth functioning.

Interference/vulnerability/Cross talk:à A disturbance caused by electromagnetic signal in another network that create confusion and cross over each other is called cross talk.

For example you are talking with your friend over a landline phone and at same time someone else who lives next to your home is talking with his friend and you find you can hear their conversation and they can hear your conversation. When you try to identify problem you find that at pole your home’s phone cable was getting touched with next home phone cable due to any reason.

This is what we call cross talk in terms of network.

Cost:à When we talk about creating a network it’s very important to identify cost of network and in most of the case a big part of money goes for cabling so having a good idea of cost of cable is assurance of making a good network.

In next few post I will explain different type of cable, there uses and other detail about cables.

In network, transmission medium is physical path between transmitter and receiver in data transmission system. The media on which data travel between sender and receiver is called transmission media.

There are 2 type of Medium

Guided Medium: à In guided medium data transmission waves are guided by solid medium path for example twisted pair cable, coaxial cable and optical fibre.

Unguided medium: àIn unguided medium data transmission wavers are transmitted through the atmosphere and including inner and outer space. Example of unguided medium is satellite, lesser and wireless transmission.

In following posts I will be writing about transmission media

Similar to bus topology from one backbone cable many other cable goes out as branches and in these branched cable switch or hub get connected similar to star topology.

Tree topology is very useful for network like colleges, universities, school and  any similar place like it where network is spread in different departments and each department has one own network but its connected with main network as well.

Tree Toplogy

It’s only applicable and recommended in big network where network is scattered in multiple branches.

Benefits of tree topology

1)      It’s supported by many of hardware and network vendor.

2)      It’s possible to connect two node point to point.

3)      All computer have their own network as well as the main network

4)      It doesn’t affect entire network if one branch goes failed

5)      Best topology for branched network where multiple different zones are there.

Drawback of tree topology

1)      Maximum Length of the network is dependent on type of cable that is in use.

2)      If main backbone fails it will take entire network down.

3)      As it’s a big network it gets difficult to maintain and create network.

As its name says mesh its really messy and very difficult to understand. In Mesh topology each node is connected with all other nodes doesn’t matter how many nodes are there. This topology is not command in LAN in fact I have never seen this in LAN.

Mesh topology is mostly used for connecting WAN network to LAN’s. Mostly ISP companies use it.In Mesh topology each node is connected with every other node so there is no chance of disconnection. It allow to communicate continuously even if anyone or 2 connection goes down.

On theoretical concept its 100 % “fault tolerant”.

Mesh Topology

In star Topology Centre point is Hub/Switch. Each node/device connects with hub/switch using a segment (a short or long distance network cable). Each node/device needs its own network cable for connecting to switch or hub. It’s easy to maintain and expand network in star topology comparison to other topologies.

Star Topology

Benefits of Star Topology

1)      Easy to add devices when need to expand network because we just need to add extra device or node without affecting other nodes.

2)      One Cable Failover does not make entire network down.

3)      Easy to find device and cables in and faulty condition.

4)      Can be upgraded to faster speed with minimum effort.

Drawback of star topology

1)      Star network require more cable then ring or bus topology network.

2)      Failure of the central hub can bring entire network down.

3)      Cost is higher (installation and equipment) comparison to bus or ring network.

4)      Bottleneck may occur if network switch is low capacity and high load comes in network.

Presently all network running in LAN are using this topology only.

As name says it, it’s a ring base topology in which network is like a ring. In this topology each node connects with 2 node and data pass through each node for its destination.

In ring topology each device has to wait for its turn for data transmit. Most common type in Ring topology is Token ring (IEEE 802.5).In token ring topology a token Contain the data, it reach to destination and then extract data. Empty token pass on for another device to use.

Ring Topology

 

 

Benefit of Ring Topology

1.      Data packet travel at great speed.

2.      No collision of data as data travel in one direction only

3.      Easier to fault find. If any point gets broken you can trace that easily.

4.      No terminator Required

Drawback of Ring topology

1.      In Ring topology it require more cable than bus topology

2.      A break in Ring will take the whole network down.

3.      Not very common so fewer devices are available and that too costly.

4.      Adding removing any node can affect entire network.

5.      Much slower in Ethernet network at normal load.