Collision Domain And Broadcast Domain

Collision Domain is the area where the collision occurs during transmission of 2 ports at same time.


When a Broadcast message is send, the devices which all receives that broadcast message is collectively called as a Broadcast Domain.

Networking Devices

1. Hub
2. Bridge
3. Switch
4. Router
5. NIC - Network Interface Card.

Crossover & Straight Through

2 types of wires depending on color codes.

Crossover wires have one end configured with 568 A and other end with 568 B.

Straight through wires have both ends configured with either 568 A or both ends with 568 B.

Crossover cables are used to connect same type of devices.
ie; to connect between a DTE and a DTE device.
or to connect between DCE and DCE device.

Straight through cables are used to connect different types of devices.
ie; to connect between a DTE and a DCE device.




* DTE and DCE is explained in one of the older post of the blog.

Color Codes

CAT 6 twisted pair cables contain 4 pairs of wires in it;  ie; 8 wires.

Orange pair - Orange & Orange White.
Green pair - Green & Green White.
Blue pair - Blue & Blue White.
Brown pair - Brown & Brown White.

2 Color Codes


568 - A
Green White
Green
Orange White
Blue
Blue White
Orange
Brown White
Brown

568 - B
Orange White
Orange
Green White
Blue
Blue White
Green
Brown White
Brown

Twisted Pair Cables

2 types of Twisted pair cables.

1. Shielded Twisted Pair (STP)
2. Unshielded Twisted Pair (UTP)

Since shielded twisted pair has an external metal shield and is costly, unshielded twited pairs is used.

UTP
Different categories based on Bandwidth.

Category 1 or CAT 1 - Used for telephone communication, not for data transmission.
Category 2 or CAT 2 - 4 Mbps
Category 3 or CAT 3 - 10 Mbps
Category 4 or CAT 4 - 16 Mbps
Category 5 or CAT 5 - 100 Mbps
Category 5e or CAT 5e - Enhanced model of CAT 5.
Category 6 or CAT 6 - 1 Gbps

DTE & DCE

Data Terminal Equipment (DTE)

Equipment where a data terminates or originates.
Used in user end devices.
We can terminate or edit data.
Eg: PC, Router.

Data Communication Equipment (DCE)

Equipment which is used for data to communicate to destnation.
Eg: Switch, Modem.

Transmission Modes

There are 3 different transmission modes

1. Simplex
    Message transmission only in one direction. No backward transmission.
    Eg: Radio.

2. Duplex
    Message transmission in both directions; one direction at a time.
    Eg: Wireless walkie talkie (one way transmisson).
    Specified one way transmission because now there is two way transmission wireless walkie talkie.
   
3. Full Duplex
    Message transmission in both directions simultaneously; both directions at a time.
    Eg: Mobile Phone.

Communication Types

3 types :-

1. Unicast
      One to one point.

2. Multicast
      One to many points.

3. Broadcast
      One to all points.

To make it simpler consider a class as an example :
A teacher is a point and each student is a point.
A teacher teaching in class is heard by all students, one to all - Broadcast.
A student was sleeping in class, teacher told that student to stand up, one to one - Unicast.
Some students failed in a test, teacher advicing the failed students to improve, one to many - Multicast.

Classification Based on Topology

Topology is a physical and logical structure of a Network
1. Bus Topology 
     Cable runs from one PCto another.
     One PC sends data. All hosts receives it and accepts only whose network address matches.
     Only one PC can send data at a time.
     The network doesnot fail if one PC fail.
     Break connector or loose connector can make whole network failed.
     Difficult to troubleshoot
     Easy to extend the network; means easy to add or install a new PC to the network.

2. Ring Topology
     All PC have same priority.
     Only one direction.
     Each PC connected to other and finally last PC conected to the first PC.
     Improved version of Bus topology.
     Each PC sends what it receives until final destination arrives.
     Whole network fails if one PC fails.

3. Star Topology
          Cable runs from PC to centralised device.
          Centralised device may be Hub or Switch.
          Easy to add a new PC thus extend network.
          Whole network doesnot fail if a PC fails.
          Major disadvantage is if central device fails whole network fails.

4. Mesh Topology
         Topology in which each node of the network is connected to each of the other nodes in the  network with a point to point link.
         This makes it possible for data to be simultaneously transmitted from a single node to all other.
         Network never goes down.

         Disadvantage : Too costly, complex for practical networks.

5. Tree Topology
         Known as hierarchial network.
         A network based upon physical hierarchial topology must have atleast three levels in hierarchy of the tree, since a network with central root node and only one level would exhibit a star topology.
     
6. Hybrid Topology
         More than one topology comes in a single network.


For images click IMAGE

Network Classification Based On AREA

1. Local Area Network (LAN)

    - Network within a single building or single area.
    - A group of computers connected at a single geographic location.
    - eg: Computers connected in a single building or different cabins of single floor are considered to be in a LAN.

2. Metropolitian Area Network (MAN)

   - 2 definitions can be given:

   - Network within a city.
      -OR-
   - Network between two or more cities.

3. Wide Area Network (WAN)

   - Network which contains different gegraphical areas is called as WAN.
     eg: Internet

4. Campus Area Network (CAN)
   - A network within a campus.
   - This connection never go beyond the campus.

5. Personal Area Network (PAN)
   - Introduced befor LAN.
   - If your personal Laptop and your personal mobile connected via bluetooth or through cable, it can be called as a PAN.

6. Storage Area Network (SAN)
   - Architecture to attach many computer storage devices.

Network And Its Classification

Interconnection of computers is called a Network.
Interconnection of 2 or more computers can be called as a Network.

Network Classification

1. Based on Area:

LAN - Local Area Network
MAN - Metropolitian Area Network
WAN - Wide Area Network
PAN - Personal Area Network
CAN - Campus Area Network
SAN - Storage Area Network

2. Based on Connectivity:

Wired
Wireless

3. Based on Topology

Bus Topology
Ring Topology
Star Topology
Tree Topology
Mesh Topology
Hybrid Topology