Computer Networks Flashcards
What is computer network?
Collection of Interconnected computers and other devices to share data and resources.
Advantages and disadvantages of computer networks?
Advantages
- Resource sharing
- Improved communication
- Central storage of data
- Reduces communication cost
- Data back-up
Disadvantages
- High cost of set up and maintenance
- Threat to data security
What is meant by ‘reliability of data’?
It means backing up of data, i.e., data can be copied and stored on multiple devices.
What was the first network that came into existence?
ARPANET, 1969
(Advanced Research Project Agency Network)
Full form of ARPANET?
Advanced Research Project Agency Network
Full form of NSFNET?
National Science Federation Network
Define internet.
Internet is a network of networks.
What is Interspace?
Software that allows multiple users in a client-server environment to communicate with each other by sending and receiving data.
It facilitates real-time exchange of data.
How does internet work?
We use modem and dial a local number to connect to an ISP.
When connected to ISP computer becomes a part of its network.
The ISP then connects to a larger network and become a part of it.
The internet is network of networks.
Full form?
ISP
POP
NAP
Internet Service Provider
Point of Presence
Network access points
What is Gateway?
What is backbone?
Gateway is a device that connects dissimilar networks.
Backbone is a central interconnecting structure that connects one or more network like a tree trunk.
What is the communication protocol used by internet?
TCP/IP
(Transmission Control Protocol)
TCP -responsible for dividing messages into packets on source computer and reassembling on the destination computer.
IP- responsible for handling the address of the destination computer
What is TCP/IP?
(Transmission Control Protocol)
TCP -responsible for dividing messages into packets on source computer and reassembling on the destination computer.
IP- responsible for handling the address of the destination computer
Define:
1. Nodes
2. Server
- Workstations.
Computers that are attached to a network. - Computer that facilitates sharing of data.
Full form:
NIU
MAC
Network Interface Unit
Media Access Control
What is NIU? Second name?
Network Interface Unit.
Helps establishing communication between server and client.
It’s also called network adapter, NI Controller
What is MAC address?
What is IP Adress?
Memory Access Control.
- identifier for NIC, network address, 12 digit hexadec
IP
- Every device connected on a TCP/IP has a identifying no. given by ISP
Components of data communication?
Sender
Reciever
Message
Transmission Medium
Protocol
Analog vs Digital transmission
Analog= broadband transmission
• it’s a radio frequency signal
• telephone network use this type
• requires modem
digital= baseband transmission
• no special device for transmission
• signal is group of discrete electrical units
• it’s rapid
Broadband vs Baseband transmission
Analog= broadband transmission
• it’s a radio frequency signal
• telephone network use this type
• requires modem
digital= baseband transmission
• no special device for transmission
• signal is group of discrete electrical units
• it’s rapid
Parallel vs Serial communication
Parallel
- data transmitted through multiple wires
- each wire carry a bit
Serial
- bits are sent one after one along the wire
Synchronous and asynchronous transmission
Sync
- sender firstvsends control characters to reciever and then sends actual data
- there’s no space between data
-faster
-costly, complex setup
-efficient for large amounts of data
Async
- data preceded and succeeded by a start bit and stop bit respectively.
- hardware simple cheap
- slow
Circuit switching
Packet switching
Message switching
Circuit
- connection oriented service
-theres a dedicated link between sender and reciever
- no other call can be made even if it’s idle
Packet
- connectionless service
-data fragmented into small packets
- data received in sequence
Message
- store and forward switching technique
- no direct connection between sender and reciever
Modem?
Modulator DEModulator
Enable computer to transmit data over telephone lines.
Device used to convert digital signal into analogue and vice versa.
RJ-45?
Registered Jack-45
- used for connecting ETHERNET and LANs
- eight wire connector
Hub
Switch
Bridge
Gateway
Hub shares bandwidth with all attached devices. Used to connect two comp with e/o.
Switch transmits data to comps in LAN
Bridge links two segments of original network together.
Gateway connects dissimilar networks.
Repeater
Router
Repeater amplifies a signal.
Router helps forwarding data packets from one machine to another using the shortest path.
TCP
IP
FTP
PPP
SMTP
POP3
TELNET
HTTP
HTTPs
(c) FTP (File Transfer Protocol)
(d) PPP (Point-to-Point Protocol)
(f) POP3 (Post Office Protocol 3)
(h) HTTP (Hyper Text Transfer Protocol)
(e) SMTP (Simple Mail Transfer Protocol)
(g) TELNET (Remote Login)
(i) HTTPs (Hyper Text Transfer Protocol Secure)
TCP (Transmission Control Protocol
IRC
VoIP
H.323
SIP
HTML
XML
URL
DNR
Domain Name Resolution
- comp finds IP of a domain
Uniform Resource Locator
Extensible Markup Language
SIP
(Session Initial Protocol)
VoIP
Voice over Internet protocol
HTTPs
s is Secure
Unguided media:
Microwave
Radio wave
Satellite link
Infra-red
Coaxial cable:
Insulated copper
Surrounding braided metal shield
Covered by plastic jacket
Good shield against noise and crosstalk
