This document provides an overview of data communication systems and computer networks. It discusses the basic components of a communication system including the message, sender, receiver, transmission medium, and protocols. It then describes different types of network topologies including bus, star, ring, and mesh. The document also defines local, metropolitan, and wide area networks and how they differ in size and scope. Finally, it discusses some important network concepts like protocols, standards, and the organizations that develop standards to ensure interoperability.
Module 1 computer networks imtroduction,data link layerDeepak John
Computer Networks Notes- Networking Concepts: Classification of networks: LAN, MAN, WAN and the Internet. Protocols and protocol architecture. The OSI ref. Model, TCP/IP ref. model, its origin, the Internet layer, the TCP layer, the application layer Comparison of the OSI and TCP/IP ref. models. A critiques of the OSI model and protocols, A critique of the TCP/IP ref. model, Novel Netware.
Data Link Layer: Need for data link control, Frame synchronization - flag fields, bit stuffing, flow control - stop and wait , sliding window protocol, error detection – parity check, CRC, Error control - Stop and wait ARQ, Go back-N ARQ, HDLC protocol, other data link protocols - LAPB, LAPD.
Introduction to the Network Layer: Network layer services, packet switching, network layer performance, IPv4 addressing, forwarding of IP packets, Internet Protocol, ICMPv4, Mobile IP Unicast Routing: Introduction, routing algorithms, unicast routing protocols. Next generation IP: IPv6 addressing, IPv6 protocol, ICMPv6 protocol, transition from IPv4 to IPv6. Introduction to the Transport Layer: Introduction, Transport layer protocols (Simple protocol, Stop-and-wait protocol, Go-Back-n protocol, Selective repeat protocol, Bidirectional protocols), Transport layer services, User datagram protocol, Transmission control protocol
Computer Networks for Computer Science Studentrprajat007
Computer Networks Notes for CS/IT students
Topics:
1.Components of Data Communication
2. Distributed Processing
3. Standards and Organizations
4. Line Configuration
5. Topology
6. Transmission Mode
7. Categories of Networks
8. OSI and TCP/IP Models: Layers and their functions, comparison of models.
9. Digital Transmission: Interfaces and Modems: DTE-DCE Interface, Modems, Cable modems.
Module 1 computer networks imtroduction,data link layerDeepak John
Computer Networks Notes- Networking Concepts: Classification of networks: LAN, MAN, WAN and the Internet. Protocols and protocol architecture. The OSI ref. Model, TCP/IP ref. model, its origin, the Internet layer, the TCP layer, the application layer Comparison of the OSI and TCP/IP ref. models. A critiques of the OSI model and protocols, A critique of the TCP/IP ref. model, Novel Netware.
Data Link Layer: Need for data link control, Frame synchronization - flag fields, bit stuffing, flow control - stop and wait , sliding window protocol, error detection – parity check, CRC, Error control - Stop and wait ARQ, Go back-N ARQ, HDLC protocol, other data link protocols - LAPB, LAPD.
Introduction to the Network Layer: Network layer services, packet switching, network layer performance, IPv4 addressing, forwarding of IP packets, Internet Protocol, ICMPv4, Mobile IP Unicast Routing: Introduction, routing algorithms, unicast routing protocols. Next generation IP: IPv6 addressing, IPv6 protocol, ICMPv6 protocol, transition from IPv4 to IPv6. Introduction to the Transport Layer: Introduction, Transport layer protocols (Simple protocol, Stop-and-wait protocol, Go-Back-n protocol, Selective repeat protocol, Bidirectional protocols), Transport layer services, User datagram protocol, Transmission control protocol
Computer Networks for Computer Science Studentrprajat007
Computer Networks Notes for CS/IT students
Topics:
1.Components of Data Communication
2. Distributed Processing
3. Standards and Organizations
4. Line Configuration
5. Topology
6. Transmission Mode
7. Categories of Networks
8. OSI and TCP/IP Models: Layers and their functions, comparison of models.
9. Digital Transmission: Interfaces and Modems: DTE-DCE Interface, Modems, Cable modems.
Academic course on Computer Network Chapter -1 for BCA, Tribhuwan University
** Applicable for other courses as well
Includes the Basic of Computer Network, Topologies, Types of Network
It covers
Definition and Objectives of computer networks
Networking models : Peer-to-Peer and Client-Server
Types of Networks : PAN, LAN, MAN, WAN
Networking Topologies: MESH, STAR, RING, BUS, HYBRID
Components of Data Communication Systems, Modes of Data Communications, Applications of Networks, Physical Topologies and their types, Categories of Networks: LAN, MAN, WAN
This chapter provides an introduction to Computer networks and covers fundamental topics like data, information to the definition of communication and computer networks.
This Presentation Covers the basic Introductions of Computer Network. It covers several topics such as Mode of Transmission, Types of Network, Data Rate, Components, etc. This would be very helpful for engineering students as well as those who are interested in Networking.
Academic course on Computer Network Chapter -1 for BCA, Tribhuwan University
** Applicable for other courses as well
Includes the Basic of Computer Network, Topologies, Types of Network
It covers
Definition and Objectives of computer networks
Networking models : Peer-to-Peer and Client-Server
Types of Networks : PAN, LAN, MAN, WAN
Networking Topologies: MESH, STAR, RING, BUS, HYBRID
Components of Data Communication Systems, Modes of Data Communications, Applications of Networks, Physical Topologies and their types, Categories of Networks: LAN, MAN, WAN
This chapter provides an introduction to Computer networks and covers fundamental topics like data, information to the definition of communication and computer networks.
This Presentation Covers the basic Introductions of Computer Network. It covers several topics such as Mode of Transmission, Types of Network, Data Rate, Components, etc. This would be very helpful for engineering students as well as those who are interested in Networking.
Multi-cluster Kubernetes Networking- Patterns, Projects and GuidelinesSanjeev Rampal
Talk presented at Kubernetes Community Day, New York, May 2024.
Technical summary of Multi-Cluster Kubernetes Networking architectures with focus on 4 key topics.
1) Key patterns for Multi-cluster architectures
2) Architectural comparison of several OSS/ CNCF projects to address these patterns
3) Evolution trends for the APIs of these projects
4) Some design recommendations & guidelines for adopting/ deploying these solutions.
Bridging the Digital Gap Brad Spiegel Macon, GA Initiative.pptxBrad Spiegel Macon GA
Brad Spiegel Macon GA’s journey exemplifies the profound impact that one individual can have on their community. Through his unwavering dedication to digital inclusion, he’s not only bridging the gap in Macon but also setting an example for others to follow.
# Internet Security: Safeguarding Your Digital World
In the contemporary digital age, the internet is a cornerstone of our daily lives. It connects us to vast amounts of information, provides platforms for communication, enables commerce, and offers endless entertainment. However, with these conveniences come significant security challenges. Internet security is essential to protect our digital identities, sensitive data, and overall online experience. This comprehensive guide explores the multifaceted world of internet security, providing insights into its importance, common threats, and effective strategies to safeguard your digital world.
## Understanding Internet Security
Internet security encompasses the measures and protocols used to protect information, devices, and networks from unauthorized access, attacks, and damage. It involves a wide range of practices designed to safeguard data confidentiality, integrity, and availability. Effective internet security is crucial for individuals, businesses, and governments alike, as cyber threats continue to evolve in complexity and scale.
### Key Components of Internet Security
1. **Confidentiality**: Ensuring that information is accessible only to those authorized to access it.
2. **Integrity**: Protecting information from being altered or tampered with by unauthorized parties.
3. **Availability**: Ensuring that authorized users have reliable access to information and resources when needed.
## Common Internet Security Threats
Cyber threats are numerous and constantly evolving. Understanding these threats is the first step in protecting against them. Some of the most common internet security threats include:
### Malware
Malware, or malicious software, is designed to harm, exploit, or otherwise compromise a device, network, or service. Common types of malware include:
- **Viruses**: Programs that attach themselves to legitimate software and replicate, spreading to other programs and files.
- **Worms**: Standalone malware that replicates itself to spread to other computers.
- **Trojan Horses**: Malicious software disguised as legitimate software.
- **Ransomware**: Malware that encrypts a user's files and demands a ransom for the decryption key.
- **Spyware**: Software that secretly monitors and collects user information.
### Phishing
Phishing is a social engineering attack that aims to steal sensitive information such as usernames, passwords, and credit card details. Attackers often masquerade as trusted entities in email or other communication channels, tricking victims into providing their information.
### Man-in-the-Middle (MitM) Attacks
MitM attacks occur when an attacker intercepts and potentially alters communication between two parties without their knowledge. This can lead to the unauthorized acquisition of sensitive information.
### Denial-of-Service (DoS) and Distributed Denial-of-Service (DDoS) Attacks
This 7-second Brain Wave Ritual Attracts Money To You.!nirahealhty
Discover the power of a simple 7-second brain wave ritual that can attract wealth and abundance into your life. By tapping into specific brain frequencies, this technique helps you manifest financial success effortlessly. Ready to transform your financial future? Try this powerful ritual and start attracting money today!
1.Wireless Communication System_Wireless communication is a broad term that i...JeyaPerumal1
Wireless communication involves the transmission of information over a distance without the help of wires, cables or any other forms of electrical conductors.
Wireless communication is a broad term that incorporates all procedures and forms of connecting and communicating between two or more devices using a wireless signal through wireless communication technologies and devices.
Features of Wireless Communication
The evolution of wireless technology has brought many advancements with its effective features.
The transmitted distance can be anywhere between a few meters (for example, a television's remote control) and thousands of kilometers (for example, radio communication).
Wireless communication can be used for cellular telephony, wireless access to the internet, wireless home networking, and so on.
APNIC Foundation, presented by Ellisha Heppner at the PNG DNS Forum 2024APNIC
Ellisha Heppner, Grant Management Lead, presented an update on APNIC Foundation to the PNG DNS Forum held from 6 to 10 May, 2024 in Port Moresby, Papua New Guinea.
1. Chapter 1
* Category of Networks * Interconnection of Networks
.The Internet
* Brief History * The Internet Today
Protocols and standards
* protocols
* Standards Organizations
* Internet Standards
3. 3
Communication Model
•Source
Generates data to be transmitted
• Transmitter
Converts data into transmittable signals
• Transmission System
Carries data
• Receiver
Converts received signal into data
• Destination
Takes incoming data
4. 4
Communication over a point-to-point link:
A simplified model
Generate
Data
Data to
Signals
Signals to
Data
Receive
Data
5. 5
Simplified Communications Model
Source (e.g. PC)
Generates data to be transmitted
Transmitter
Converts data into transmittable signals (modulation, encoding)
Transmission System (medium + equipment)
Carries signals, but introduces attenuation, noise, interference, etc.
Receiver
Converts received signals into data (demodulation, decoding)
Destination
Takes and uses incoming data
SignalData
1101...
Data
1101…
Noise, Distortion
Interference
Attenuation
6. 6
Interfacing Addressing
Signal generation Routing
Synchronization Recovery
Exchange management: Message formatting
Error detection and correction Security
Error control Network management
Flow control Transmission system utilization
= Tasks covered in some detail in this course
SignalData
1101...
Data
1101…
Noise, Distortion
Interference
Attenuation
Tasks covered in some detail in this course
8. 1- Data communications
Data communication : Is the exchange of
data between devices via some form of
transmission medium such as a wire cable .
For data communication to occur , the
communicating devices must be part of
communication system made up of a
combination of
1- Hardware ( physical equipment )
2- Software (programs)
9. Block diagram of data communication system
Sender Receiver
Massage
Protocol
Rule 1
Rule 2
Rule 3
Rule 1
Rule 2
Rule 3
Protocol
Medium
10. Component of Data
communications system
Data communications system has five components:
1- Message : is the information (data) to be
communicated such as ( text – picture – audio –
video) .
2- Sender : the device that sends the data massage
such as ( computer – workstation – telephone –
video camera )
3-Receiver : is the device that receives the massage
such as ( computer – workstation – telephone –
video camera )
11. 4- Transmission medium : is the physical path
by which a massage travels from sender to
receiver such as ( Twisted pair wire – Coaxial
cable – fiber optic cable - Radio waves)
5- Protocol : is a set of rules that govern data
communications. It represents an agreement
between the communicating devices . Without a
Protocol , Tow devices may be connected but
not communicating . Just as a person speaking
French can not be understood by a person who
speaks only Japanese .
12. The effectiveness of data communications
system depend on four fundamental
characteristics :
1- Delivery 2- Accuracy
3- Timelines 4- Jitter
Fundamental characteristics
of Data communications
13. 1- Delivery : the system must deliver data to the
correct destination
2- Accuracy : the system must deliver data accurately .
3- Timelines : the system must deliver data in a timely
manner . Data delivered late are useless .
4- Jitter : refers to the variation of the packet arrival
time it is the uneven delay in the delivery of data .
Fundamental characteristics
of Data communications
15. Data Flow
Communication between two devices can be :
1- Simplex : in simplex mode the communication is
unidirectional , as on a one way street .only one of the
two devices on a link can transmit ; the other can only
receive .
• Example of simplex devices . The keyboard can only
introduce input & the Monitor can only accept output .
• * the simplex mode can only the entire capacity of the
channel to send data in one direction .
16. Data Flow
2- Half - Duplex : Each station can both transmit
and receive , but not at the same time .
When one device is sending the other can only
receive and vice versa
In half-Duplex transmission , the entire of
channel is taken over by whichever of the two
devices is transmitting at the time .
Example on Half Duplex is walkie-talkies.
17. Data Flow
3- Full-Duplex :
In the full-Duplex mode , both station can transmit and
receive simultaneously.
- Signal going in one direction share the capacity of the link with
signals going in the other direction . This share can occur in two
ways :
- Either the link must contain two physically separate
transmission paths one for sending and the other for
receiving
or The capacity of the channel is divided between signals
traveling in both direction
• The full -Duplex mode is used when communication in both
directions is required all the time. The capacity of the channel
must be divided between the tow directions.
• EX: The Telephone Network.
20. Half duplex: one way at a time
CPU
Memory
Storage
CPU
Memory
Storage
Programs send messages to and from each others’ memories
21. Full duplex: both ways at the
same time
CPU
Memory
Storage
CPU
Memory
Storage
Programs send messages to and from each others’ memories
22. Networks
A network is a set of devices (nodes ) connected by
communication links , A node can be a computer,
printer , or any other device capable of sending or
receiving data generated by other nodes on the network
Distributed processing : Task is divided among
multiple computers instead of single large machine.
Network Criteria : A network must be able to meet
a certain number of criteria , the most important of this
are : 1-performance 2- reliability 3-security .
23. 1- Performance : can be measured in many ways , including
transit time and response time .
- Transit time : is the amount of time required for a message to
travel from one device to another .
- Response time : is the elapsed time between an inquiry and a
response .
- The performance of a network depends on a number of
factors , including:
1- The number of users 2- the type of transmission medium
3- The capabilities of the connected hardware
4- The efficiency of the software
- performance is often evaluated by two network matrices :
throughput and delay.
24. 2- Reliability : in addition to accuracy of delivery ,
network reliability is measured by the frequency of
failure , the time it takes to recover from
a failure , and the network’s robustness in
a catastrophe
3- Security : network security include protecting data
from unauthorized access , protecting data from
damage development , and implementing policies
procedures for recovery from preaches and data
losses
25. Physical Structures
We need to define some network attributes :
type of connection : there are two possible type of connections:
1- Point to Point .
2- point to Multipoint.
26. Physical Topology
Physical topology refers to the way in which
a network is laid out physical .
The topology of a network : is the trigonometric
representation of the relationship of all the links
and linking devices.
27. Categories of Networks
Computer networks can be classified according
to their size to three categories :
1- Local Area Network (LAN)
2- Metropolitan Area Network (MAN)
3- Wide Area Network (WAN)
28. 1.28
NETWORKS
A network : is a set of devices (often referred to as nodes)
connected by communication links.
A node can be a computer, printer, or any other device
capable of sending and/or receiving data generated by
other nodes on the network.
Distributed Processing
Network Criteria
Physical Structures
Network Models
Categories of Networks
Interconnection of Networks: Internetwork
Topics discussed in this section:
29. • A LAN is a network that is used for communicating among
computer devices, usually within an office building or home
• LAN’s enable the sharing of resources such as files or
hardware devices that may be needed by multiple users
• Is limited in size.
• Speed from 10 Mbps to 10 G bps
• Has lower cost compared to MAN’s or WAN’s
• Example: The Ethernet (IEEE 802.3 standard
• Data rates are higher (this is made possible by the shorter distances-
small total attenuation can afford using higher frequencies, e.g.:
Ethernet: 10 Mbps -10 Gbps over 100’s of meters
Originally use a shared broadcast medium, e.g. coaxial cable
1- Local Area Network ( LAN)
30. 30
Metropolitan Area Network (MAN)
networks that cover a single city
hom
e
cable headend
cable distribution
network (simplified)
31. 2-Metropolitan Area Network (MAN )
Is a network with a size between a LAN and WAN .
It normally covers the area inside a town or city .
Requirements: Large capacity (data rate) at low
cost and high efficiency
Can be a private or public network
Middle ground between LAN and WAN:
Stretching of LAN technology
Scaling down of WAN technology
Now also going wireless!:
Example: WiMAX (IEEE 802.16 standard
32. 32
Wide Area Network (WAN)
What is a WAN?
A WAN (Wide Area Network) : allows you to connect
to other computers over a wider area (i.e. the whole
world).
Can span the world or link computers across town
Components
Communications services
WAN hardware
WAN software
33. 3- Wide Area Network (WAN )
Provides long distance transmission of data.
It has no geographical limit .
A WAN is made up of a number of interconnected LANs.
Ex : Internet
o Large geographical area, e.g. the world
o Usually not owned by one organization
o Alternative technologies
o Circuit switching, e.g. telephone network, ISDN*
o Packet switching, e.g.:
o Frame relay
o Cell relay (Asynchronous Transfer Mode (ATM))
36. LAN Basics
LAN’s can be either wired or wireless.
Twisted pair, coaxial or fiber optic cable can be
used in wired LAN’s
Nodes in a LAN are linked together with a certain
topology. These topologies include:
Bus
Ring
Star
Mesh
Branching tree
37. 37
Network Topology
The physical layout of
a network
Node - each computer,
printer, or server on network
Three common topologies
Bus
Ring
Star
38. Network Topologies
1- Bus Topology
Each node is connected one after the other
Nodes communicate with each other along
the same path called the backbone
39. 1- Bus topology
-Each node is connected one after the other .
-Computers send messages to other computers on network
If messages collide with other messages, sending
nodes resends their message again.
collision
terminator
terminator
41. Advantages of Bus Topology
1- Use of cable is economical
2- media is inexpensive and easy to work with it.
3- Easy to be extended
4- if any computer on the Bus stopped to work,
that does not effect on the entire network.
42. Disadvantages of bus topology
1- Network can slow in heavy traffic.
2- Cable break effect on the entire network.
3- Number of computers is limited.
43. 2- Ring topology
-The ring network is like a bus network, but the
“end” of the network is connected to the first node.
-Nodes in the network use token to communicate with
each other.
Backbone
Node
Node
44. 2- Ring Topology
*Advantages
- High performance ,despite many users.
*Disadvantages
- Failure of one computer can impact the rest of
the network.
-Failure of one cable impact the entire network
45. 3- Star Topology
Each node is connected to a device in the center
of the network called a hub
The hub simply passes the signal arriving from
any node to the other nodes in the network
The hub does not route the data
Hub
Node
Node
46. Advantages
Adding new computers is easy.
- centralized monitoring and management are
possible .
- failure of one computer does not affect the rest of
the network.
Disadvantages
1- If the centralized point fails the entire network
will be got down also.
2- Many cables are used for connection.
Star Topology
47. 4- Mesh topology
FULLY CONNECTED
Advantages
System increased redundancy and reliability.
Disadvantages
system is expensive to install because it uses a lot of
cabling.
PC
49. Q (a) For each of the following four networks, discuss the
consequences if a connection fails in :
(1) Five devices arranged in a mesh topology
(2) Five devices arranged in a star topology (not counting the
)hub)
(3) Five devices arranged in a bus topology
(4) Five devices arranged in a ring topology
An.
•If a connection fails in five devices arranged in a mesh topology: if one connection
fails , the other connection will still be working.
• If a connection fails in five devices arranged in a star topology The other devices
will still be able to send data through the hub ; their will be no access to the device
which has the failed connection to the hub.
•If a connection fails in five devices arranged in a bus topology: All transmission
stops if the failure is in the bus . if the drop- line fails , only the corresponding
device cannot operate.
•If a connection fails in five devices arranged in a ring topology: The failed
connection may disable the whole network unless it is a dual ring or there is a by-
pass mechanism.
50. Protocols and Standards
Protocol : is a set of rules that govern data
communications. It represents an agreement
between the communicating devices .
Without a Protocol , Tow devices may be connected
but not communicating.
The key element of a Protocol are:
1- Syntax
2- Semantics
3-Timing
51. Protocol
1- Syntax : is the structure or format of data .
- For example : a simple protocol might expect
the first 8 bit of data to be the address of the
sender , the second 8 bits to be the address of
the receiver ,and the rest of the stream to be the
massage itself.
2- Semantics : refers to the meaning of each
section of bits
52. Protocol
3- Timing : refers to two characteristics
1- when data should be sent
2- how fast they can be sent
Ex : if a sender produces data at 100 Mbps but
the receiver can process data at 1 Mbps , the
transmission will overload the receiver and some
data will be lost
53. Standards
Standards : are necessary to ensure that
products from different manufacturers can work
together as expected .
Examples on some organizations involved in
standards creation are :
1- International organization for standardization
(ISO)
2-Institute of Electrical and Electronic Engineers
(IEEE)