Chapter 1: Computer Networks

Computer Networks

Computer Networks

A system of interconnected computers and devices that allows for the sharing of resources and information.

Uses of Computer Networks

Various applications of computer networks, including access to information, person-to-person communication, electronic commerce, entertainment, and the Internet of Things.

Types of Computer Networks

Different categories of computer networks, such as broadband access networks, mobile and wireless access networks, content provider networks, transit networks, and enterprise networks.

Network Technology, from Local to Global

The progression of network technology from personal area networks to local area networks, home networks, metropolitan area networks, wide area networks, and internetworks.

Examples of Networks

Specific examples of networks, including the Internet, mobile networks, and wireless networks (WiFi).

Network Protocols

The design goals, protocol layering, connections and reliability, service primitives, and the relationship of services to protocols in network communication.

Reference Models

The OSI Reference Model, the TCP/IP Reference Model, a critique of these models, and the model used in the book.

Standardization

The importance of standardization in network communication and the key players in the telecommunications, international standards, and internet standards worlds.

Policy, Legal, and Social Issues

The impact of computer networks on online speech, net neutrality, security, privacy, and disinformation.

Metric Units

The use of metric units in the context of computer networks.

Outline of the Rest of the Book

An overview of the topics covered in the remaining chapters of the book.

Summary

A brief summary of the key points discussed in the chapter.

Optimality Principle

A principle in routing algorithms that states that the best route for a packet is the one with the lowest cost or shortest path.

Shortest Path Algorithm

An algorithm used in routing to find the shortest path between two nodes in a network.

Flooding

A routing technique where a packet is sent to all neighboring nodes in a network.

Distance Vector Routing

A routing algorithm where each node maintains a table of the distance to all other nodes in the network.

Link State Routing

A routing algorithm where each node maintains a map of the entire network and uses this information to determine the best path for a packet.

Hierarchical Routing within a Network

A routing technique where a network is divided into multiple levels or hierarchies, with each level responsible for routing within that level.

Broadcast Routing

A routing technique where a packet is sent to all nodes in a network.

Multicast Routing

A routing technique where a packet is sent to a specific group of nodes in a network.

Anycast Routing

A routing technique where a packet is sent to the nearest node among a group of nodes with the same address.

Traffic Management

The process of controlling and optimizing the flow of data in a network to prevent congestion and ensure efficient use of network resources.

Congestion

Refers to a state where too much traffic in a network causes lowdown; reducing efficiency of data transfer.

Approaches to Traffic Management

Different strategies and techniques used to manage and control traffic in a network, such as prioritization, queuing, and resource allocation.

Application QoS Requirements

The specific quality of service requirements and expectations of an application, such as bandwidth, latency, and reliability.

Overprovisioning

A strategy of allocating more network resources than necessary to ensure that the network can handle peak traffic loads.

Packet Scheduling

The process of determining the order in which packets are transmitted in a network to optimize performance and meet quality of service requirements.

Integrated Services

A network architecture that provides different levels of quality of service for different types of traffic, such as voice, video, and data.

Differentiated Services

A network architecture that classifies and prioritizes packets based on their specific requirements and assigns them to different service classes.

Internetworks

The connection of multiple networks to create a larger network.

How Networks Differ

The ways in which different networks can vary in terms of their protocols, technologies, and architectures.

Connecting Heterogeneous Networks

The process of connecting networks that use different protocols or technologies to enable communication between them.

Connecting Endpoints Across Heterogeneous Networks

The process of enabling communication between endpoints that are connected to different networks.

Internetwork Routing

Routing Across Multiple Networks:The process of routing packets across multiple networks in an internetwork.

Supporting Different Packet Sizes

Packet Fragmentation:The process of breaking up packets into smaller fragments to accommodate networks with different maximum packet sizes.

Software-Defined Networking

An approach to networking that separates the control plane from the data plane and allows for centralized control and programmability of network devices.

Logically Centralized Software Control

The centralized component of a software-defined network that is responsible for making routing and forwarding decisions.

Programmable Hardware:

The hardware component of a software-defined network that is responsible for forwarding packets based on the decisions made by the control plane.

Programmable Network Telemetry

The ability to collect and analyze data about the performance and behavior of a network in real-time using programmable network devices.

The IP Version 4 Protocol

The fourth version of the Internet Protocol, which is the most widely used protocol for routing packets on the Internet.

IP Addresses

Unique numerical identifiers assigned to devices connected to a network that are used for routing packets.

IP Version 6

The sixth version of the Internet Protocol, which was developed to address the limitations of IPv4 and provide a larger address space.

Internet Control Protocols

Protocols used for managing and controlling the operation of the Internet, such as ICMP (Internet Control Message Protocol) and IGMP (Internet Group Management Protocol).

Label Switching and MPLS

A technique used in routing to improve the efficiency and speed of packet forwarding by assigning labels to packets and using them to make forwarding decisions.

OSPF—An Interior Gateway Routing Protocol

Open Shortest Path First (OSPF) is an interior gateway routing protocol used to determine the best path for routing packets within an autonomous system.

BGP—The Exterior Gateway Routing Protocol

Border Gateway Protocol (BGP) is an exterior gateway routing protocol used to determine

Computer Network

A collection of interconnected, autonomous computing devices that can exchange information.

Access to Information

The ability to retrieve and view information from various sources, such as websites, social media platforms, and online libraries.

Web Browser

A software application that allows users to access and retrieve information from websites.

Interconnected

Two computers are said to be interconnected if they can exchange information.

Transmission Media

The physical medium through which information is transmitted, such as copper wire, fiber optic cable, or radio waves.

Network of Networks

A larger network formed by connecting multiple smaller networks, with the Internet being the most well-known example.

News Curation

The process of selecting, organizing, and presenting news content to users, often personalized based on user preferences and machine learning algorithms.

Online Publishing

The distribution of news and other content through online platforms, often replacing traditional print operations.

Digital Libraries

Online repositories of digital content, such as academic journals, books, and conference proceedings.

Client-Server Model

A model in which a client requests information from a server that hosts that information.

Function of the Client-server model

A widely used network model where a server generates web pages based on its database in response to client requests.

Peer-to-peer communication

A network model where individuals in a loose group can communicate with each other without a fixed division into clients and servers.

BitTorrent

A peer-to-peer system that does not have a central database of content, where each user maintains a local database and can access content from other members of the system.

Napster

A music sharing service that popularized peer-to-peer communication but was shut down due to copyright infringement.

Person-to-person communication

Communication between individuals using email, instant messaging, and social networking applications.

Internet of Things (IoT)

The ongoing revolution of connecting electronic devices to the internet, allowing for increased automation and communication between devices.

Broadband access networks

Networks that provide high-speed internet access to homes and businesses through various technologies such as copper, coaxial cable, or optical fiber.

Mobile and wireless access networks

Networks that enable connectivity for mobile devices such as laptops, tablets, and smartphones, allowing users to access the internet from anywhere.

Wireless Networks

Networks that enable connectivity to the Internet without the need for wired connections.

Cellular Networks

Wireless networks operated by telephone companies that provide coverage for mobile phones.

Wireless Hotspots

Wireless networks based on the 802.11 standard that provide coverage for mobile computers and portable devices.

Fleet Connectivity

The use of wireless networks for keeping in contact with a home base for fleets of trucks, taxis, delivery vehicles, and repair-persons.

Mobile and Wireless Networking in Ground Transportation

The use of mobile and wireless networking in ground transportation, enabling services like ride-sharing companies such as Uber and Lyft.

Military Applications

The importance of wireless networks in the military for ensuring connectivity in any location.

Distinction between Wireless Networking and Mobile Computing

The difference between wireless networking and mobile computing, where wireless networking refers to the connectivity aspect and mobile computing refers to the use of mobile devices.

Wireless Connectivity in Homes and Offices

The convenience of wireless connectivity for desktop computers or media players in homes, offices, or hotels without suitable cabling.

True Mobile, Wireless Applications

Examples of true mobile, wireless applications such as handheld computers for store inventory or mobile devices for car rental return clerks.

Mobile Phones and Convergence with the Internet

The convergence between mobile phones and the Internet, leading to the growth of mobile applications.

Location-Based Services

The use of GPS and Wi-Fi hotspots to determine the location of mobile devices and enable location-dependent services.

Mobile Commerce

The use of mobile phones for m-commerce, including mobile payments and interactions with nearby readers for payment.

Sensor Networks

Networks of nodes that gather and relay information about the physical world, enabling applications like tracking migration or gathering data from cars.

Content Delivery Networks (CDNs)

Networks that distribute content geographically to serve users requesting it, used by large content providers like Google and Netflix.

Transit Networks

Networks that carry traffic between independently operated networks, often used when the content provider and the ISP are not directly connected.

Enterprise Networks

Networks within organizations that connect computers and enable data sharing and resource sharing among employees.

Resource sharing

Making programs, equipment, and data available to other users on the network without regard to physical location.

Virtual Private Networks (VPNs)

Networks that connect individual networks at different sites into one logical network, allowing users to access data as though it were local.

Tyranny of geography

The concept of overcoming the limitations imposed by physical distance through network connectivity.

One of the major goals in Enterprise Networks

Client

The user's computer or device that accesses remote data or resources.

Server

Powerful computers that store and maintain data and resources, accessed by clients.

IP telephony or VoIP

Technology that allows telephone calls between employees to be carried by the computer network instead of the phone company.

Video conferencing

A form of communication that combines audio and video to enable multiple employees at distant locations to see and hear each other during meetings.

Desktop sharing

Allowing remote workers to see and interact with a graphical computer screen, facilitating collaboration and real-time document editing.

Electronic mail (email)

A common form of communication among employees in which messages are sent electronically.

Personal Area Networks (PANs)

Networks that allow devices to communicate over the range of a person, often using wireless technology.

Bluetooth

A short-range wireless network technology used to connect devices without the need for cables.

Local Area Networks (LANs)

Private networks that operate within and nearby a single building, connecting personal computers and consumer electronics to share resources and exchange information.

IEEE 802.11 (WiFi)

A popular standard for wireless LANs that operates at various speeds.

Switched Ethernet

The most common type of wired LAN, where computers connect to a switch that relays packets between them.

Virtual LANs (VLANs)

Dividing a large physical LAN into smaller logical LANs for easier management and organization.

Dynamic allocation

Allocating network resources on demand, rather than using a static allocation method.

Centralized channel allocation method

A dynamic allocation method in which a single entity, such as a base station, determines the order of transmission by accepting and prioritizing packets according to an internal algorithm.

Decentralized channel allocation method

A dynamic allocation method in which there is no central entity, and each machine must decide for itself whether to transmit.

Home networks

LANs in the home that consist of a diverse range of Internet-connected devices and require easy management, dependability, and security.

Internet of Things (IoT)

The proliferation of Internet-connected appliances and consumer electronics that allows for the connection of various electronic devices to the Internet.