what is the network?

it's and hardware and software involed in the connections and communcations
for computer in large and small distant

what is the important of network?

1. easy access information
2. sharing of expensive devices resouces over the network
3. modern techology

what is the main three component of network?

• connected devices: mobile , server , host2, network applications
• network device: switch, router, modems, repeaters
• connentivity: media that connect the computer and networks

what is benefits of network?

• lower cost
• centralized administration
• avolid file duplication
• increase communcation capacity
• fewer computer need

what is network types(size)?

• pan(personal area network): for personal usedge
• lan(local area network): for a group of networks that work in small area
• can(campus area network): using for school campus of unversity campus
• man(metrapoliation area network): it's a group of lans that are interconnected
  with an asmall area
• wan(wide area network): it's a group of lans that area interconnected in
  large area

what is isp mean?

it's stand for interent service provider

what is internet & intranet & extranet?

internet it's a glabol network for all users, intranet: private design used by
organization employees, extranet: compeny network accessible by authorized
outsiders

what is a virtual private network?

private secuire path over internet provide a secure private network via internet

what is network topologies?

physical topology: descirbe how the device physically cabled
logical topology: descirbe how devices communcation accross each other
(broad cast, multicast, unicast)

explain all network topologies?

star network: all network device connected to center device
bus network: all network device connected to center cable
mesh network: multiple connectations amoung the network devices

what is peer-to-peer?

• center server is not used
• all computers on the network work at the same functional level
• users have direct access to all computer in the network
• less complicated and less expensive
• context(data) is exchange over the network direcet

what is data transmission?

• simplex tarnsmission: data travel in singel direction
• half duplex transmission: data travel eithor direction
• full duplex transmission: data travels both direction

what is networking media?

• wired networking media:

  • twisted pair cable: a insulated wires twisted togthers
    (telephone, netwrok connections)
  • coaxial cable: thick center cable surrounded by isulations(television)
  • fiber-obtic cable: using for high speed communcations

• wirelesss networking media:

  • data send through airwaves using radio signals
  • the electronmagnetic and wirless specturm

what is nic do?

• prepare data from computer to netwrok cable
• generatic a electronic signal to travel through cable
• following specific rules controlling access to the cable
• contorl the flow of data thorugh the cable
• recive incoming data from the cable and tarnslates it into bytes

what is repeater?

repeater is actually boosts the signal through the cable before it's send
a way

hubs:

a center component for star topology,

active hub:-

most hubs are active in that they regenerate and retransmit the signals
the same way a repeater does.

passive hubs:-

they act as connection points and do not amplify or regenerate the signal;
the signal passes through the hub.
passive hubs do not require electrical power to run

hybrid hubs

advanced hubs that will accommodate several different types of cables
are called hybrid hubs.

physical layer:

is responseable for moving individual bits from one hop(node) to another..

data link:

is responsible for moving frames from one hop(node) to another...

the network layer:

is responsible for routing an individual packets from the source to the
destination host

transport layer:

is response from delivery of message from one process to another and
segmentation and error detaction

session layer:

for setup and managnment and traminate a session

presentation layer:

responsible for translatatoin, compresssion, encryption

application layer:

response for providing service to user like web browser it's handle to talk
with other server like knowing the https and ftp and else

ISO/OSI and TCP/IP Models Overview

Notes:

• 21: FTP
• 25: SMTP
• 80: HTTP
• 443: HTTPS
• 53: DNS
• 110: POP3
• 143: IMAP

2. Protocol and Datagram Mapping:
   • OSI layers define detailed functionalities, while TCP/IP
     merges some layers for simplicity.
   • Physical and data link layers in OSI are combined
     as the "Link Layer" in TCP/IP.
3. The Session and Presentation Layers are typically handled by the
   application layer in modern TCP/IP models.

in TCP/IP model:

• Application layer: Include stream of bits which a browser should send.
• Transport layer : Data is broken into smaller size segments by TCP
• Network Layer: The segments are broken into smaller packet appended
  with IP header of size 20 bytes to 60 bytes. The IP header consists of
  source IP address, Destination IP address, and break the data into packets
• Data link layer: breaks the packet into frames add source MAC address,
  destination MAC address.
• Physical Layer: Actual data transfer (wireless, wired, optical)

Difference Between Tier 1, Tier 2, and Tier 3 ISPs

Tier 1 ISPs:
Provide direct access to the global Internet backbone.
Examples: AT&T, Verizon, TeliaSonera.
Tier 2 ISPs:
Regional ISPs that connect to Tier 1 ISPs for Internet access.
Often peer with other Tier 2 ISPs to reduce costs like (Telecom Egypt).
Tier 3 ISPs:
Provide local access to end-users (home or business customers).
Rely on Tier 2 or Tier 1 ISPs for upstream connectivity.
Known as "last-mile providers.", like "we, tedata"

what is ip spoofing?

injection of packets with false source address

what is throughput?

rate with btis that are send or recive from source to reciver

what is packet sniffing?

broadcat media (sharing ethernet), netwrok interface read records

denial of service (Dos)?

attackers make resources unavailable to traffic by overwhelming resouces
with bogus traffic

what is key security?

• authentication: proving you are who you are say..
• confidentiality: via encryption
• access restricitions: password protections

what is the www?

elso called is world wide web is collection of website that stored in web server
and connected to local computer through the networks

what is a server?

is a computer that store a compenets of website online

what is domain name?

is the text that the user type in the browser to search for for particular website
and it's unique name

what is URL?

is uniform resouces alocator

what is domain extensions?

also referred to top level domain this a series of letters that come in the end
of domain like .com ,.org

what is hyprlinks?

is a text or images or links that referred to another web page

what is web hosting?

it is nesserary to store a web site online where it is always avaliable for
every one

what is search engine?

allows us to search for specific information online or visit website that
are public and avaliable for every one

what is benefits of haveing a website?

1. cost effective: for compeny to very cheap for advertisement a product online
2. business credibility: when customer like the website gone have a greater chance
   of considering your business over another company
3. around the clock avaliabile: it's like 24hours par 7 days
4. increased sales: a good website gone have increased the sales
5. build a customer base: using a website you can build a customer based

what is the components of a website?

• goal
• domain
• domain registeraiot
• web hosting service
• design
• content

what is html??

it's an hyprtext markup language