Connecting computers together so that you can exchange information between them
Network in small geographical area
- (Room, Building or Campus)
- LAN (Local Area Network)
Network in a City
MAN (Metropolitan Area Network)
Network spread geographically.
- (Country or across Globe)
- WAN (Wide Area Network)
Advantages of Networking
- Availability of data any time, anywhere irrespective of the physical origin of the data.
- Resource sharing minimizes resource requirements.
- Ease of managemet
Any computer that serves something to other computers in the network.
Any computer in a network that takes some kind of service from another computer (server)
A Windows 2003 server serving IP addresses to other computers in the network is called _____/
The method or protocol by which data is sent from one computer to another on the internet where each computer (known as a host) on the internet has at least one IP address that uniquely identifies it from all other computers on the Internet.
A Windows XP computer with a printer attached to it & allowed other computers in the network to print to it is called a ______.
International Organization for Standardization
Open System Interconnect
OSI Layers Advantages?
- Makes easy to understand the process of networking.
- Helps in defining the role of a product in a network & its specifications.
- Standard specifications provide compatibility between products from different manufacturers.
- - Seven Layer Model?
- 1. Physical
- 2. Data Link
- 3. Network
- 4. Transport
- 5. Session
- 6. Presentation
- 7. Application
Deals with end to end communications between data source and destinations.
Layers 7 through 4
Deals with communications between network devices.
Layers 3 to 1
Deals with the Physical Connection between the computers.
Provides specifications for building a physical infrastructure of a network...TOPOLOGY
Under Physical Topologies
- Extended Star
Defines the way in which computers, printers, and other devices are connected.
Describes the layout of the wire and devices as well as the paths used by data transmissions.
Commonly referred to as a "Linear Bus".
- All the devices on a bus topology are connected by one single cable.
- Bus Topology
The most commonly used architecture in Ethernet LANs.
- - when installed, resembles spokes in a bicycle wheel.
Larger networks use the extended star topology also called as ____.
- When used with network devices that filter frames or packets, like bridges, switches, and routers, this topology significantly reduces the traffic on the wires by sending packets only to the wires of the destination host.
- Tree Topology
All the devices on the network share a single cable.
Allows data to be sent in both directions.
Connects all devices (nodes) to each other for redundancy and fault tolerance.
Used in WANs to interconnect LANs and for mission critical networks like those used by banks and financial institutions.
Expensive and Difficult.
A copper-cored cable surrounded by a heavy shielding and is used to connect computers in a network.
Used to regenerate the weakened signals.
Impedance and Use of
- 50 ohms
- Thin Ethernet
Impedance and Use of
- 50 ohms
- Thick Ethernet
A type of cabling that is used for telephone communications and most modern Ethernet networks.
2 Basic Types of Twisted Pair
- Shielded Twisted-Pair (STP)
- Unshielded Twisted-Pair (UTP)
Consists of 4 pairs (8 wires) of insulated copper wires typically about 1mm thick.
Flexible and Cheap cable.
CAT3, CAT4, CAT5, Enhanced CAT5 and now CAT6.
Categories of UTP
- Category 3
- Category 5e and Category 6
The wiring used primarily for telephone connections.
Currently the most common Ethernet cables used.
Category 5e and Category 6
Uses light to send information through the optical medium.
Has a very small core and carry only one beam of light. It can support Gbps data rates over >100Km without using repeaters.
Carries light pulses along single path
Uses Laser Light Source
Many pulses of light generated by LED travel at different angles.
Contains one or several glass fibers at its core.
Surrounding the fibers is a layer called _________.
FO Cable may have ___ to over ____ fibers.
Very useful in difficult terrain where cable laying is not possible.
Provides mobility to communication nodes.
Modulation scheme used in Fiber Media.
Microwaves do not follow the curvature of earth.
Used to increase the distance hop-by-hop
Allows the signal to travel faster.
Deals with how computers transmit data on the media i.e. cable.
Data Link Layer
Carrier Sense Multiple Access
Method by which computers send or receive data using a single media.
Carrier Sense Multiple Access
When 2 computers send data at the same time on the cable.
Collision / Data Collision
2 methods used to deal with Data Collisions
- Collision Detection
- Collision Avoidance
In this method, when collision happens, both the computers sending data stop transmission.
In this method, care is taken so that there will be no collisions.
The part of the Data Link Layer which deals with how computer access the media and how the computers will be identified.
MAC (Media Access Control) Sub layer
- - - thus this number is called MAC Address
- - also called :
- Physical Address
- Hardware Address
- - It is ___ bits Hexadecimal number.
Receives the announcements & creates a list of all the computers in a network.
broadcast MAC Address?
The part of the data link layer which deals with the actual communication between the computers.
Logical Link Control
The Logic Link Control (LLC) sub layer does what two things?
- Flow Control
- Error Control
This controls the amount of data that is transferred between the computers at a time during the communication.
2 methods of Flow Control
- Data is sent at a fix rate throughout the communication.
- Data is sent at a varying rate depending on status of both the computers.
This checks for any errors in the data during transmission of the data over the media.
Used by both transmitting & receiving computer to check for any errors in the data.
Cyclic Redundancy Check (CRC) Method
The data at the physical layer is in the form of _________.
The data at the Data Link Layer is organized in the form of ______.
A data packet which every computer in the network has to receive.
The name of the 3rd OSI Layer