Networking

Average throughput is the rate over a longer period of time.

IP spoofing is the technique of sending a packet with a false source address, allowing an attacker to disguise their identity.

The Internet structure is described as a network of networks, where various access ISPs connect to each other.

The traceroute program is a tool that provides delay measurement from the source to each router along the end-to-end Internet path towards a destination by sending packets and timing the interval between transmission and reply.

A method of data transmission where hosts break application-layer messages into packets and forward them from one router to the next across links, utilizing full link capacity for each packet.

A packet arriving at a full buffer is lost, which means it may not be transmitted and could require retransmission by a previous node, the source end system, or may not be retransmitted at all.

An Internet exchange point (IXP) is a physical infrastructure that allows different Internet Service Providers (ISPs) to interconnect and exchange traffic directly, improving efficiency and reducing costs.

The Internet is described as a 'network of networks' that interconnects various Internet Service Providers (ISPs).

The original vision for the Internet was 'a group of mutually trusting users attached to a transparent network', indicating that security was not a primary consideration.

Using different frequency channels for multiple radio stations broadcasting simultaneously.

Propagation time is calculated by dividing the distance (100 km) by the speed (100 km/hr), resulting in a time of 1 hour for the last car to reach the second toll booth.

Protocol Layers are a way to organize the complex structure of networks by categorizing different components such as hosts, routers, links, applications, and protocols into distinct layers for easier management and understanding.

Functionality at one layer may require information that is only available in another layer, complicating interactions between layers.

A bottleneck link is the link on the end-to-end path that constrains the end-to-end throughput.

An Ethernet switch is a device that connects end systems in a network, allowing them to communicate with each other.

The term 'network of networks' refers to the interconnected structure of multiple individual networks (ISPs) that together form the global Internet.

It means that Internet protocol designers are trying to address security concerns after the fact, as the Internet was not initially designed with robust security measures.

Packet sniffing is the process of capturing and analyzing packets of data as they travel across a network, often using a promiscuous network interface that reads all packets, including sensitive information like passwords.

The result of the Internet being a network of networks is a very complex structure that enables global connectivity.

A device that modulates and demodulates signals for data transmission over cable television networks.

Link capacity R_c represents the maximum rate at which bits can be received by the client, measured in bits per second.

It indicates that the average queueing delay is large, meaning more work is arriving than can be serviced, potentially leading to infinite average delay.

Layering allows for changes in the implementation of a layer's service to be transparent to the rest of the system, meaning that modifications can be made without affecting other layers.

Delay in packet transmission is caused by packets queuing in router buffers while waiting for their turn to be transmitted.

The service options provided by the Internet are analogous to those of a postal service.

The Internet structure is a complex arrangement of interconnected networks that collectively function as a single global network.

Customer ISPs are those that purchase Internet access from Provider ISPs, which are larger ISPs that have direct connections to the global Internet and provide services to smaller ISPs.

The caravan analogy compares cars to bits and a caravan to packets, illustrating how data is transmitted through a network, similar to how a line of cars moves through toll booths.

Unlike DSL, which provides dedicated access to a central office, cable networks allow multiple homes to share access to the cable headend.

A model consisting of the Transport, Application, Network, Link, and Physical layers used to facilitate communication over the Internet.

A conceptual framework that standardizes the functions of a telecommunication or computing system into seven abstraction layers: Transport, Session, Application, Presentation, Network, Link, and Physical.

A device that divides a single cable signal into multiple outputs for connecting several devices to the same cable line.

A digital photo frame that connects to the internet to display images and can receive photos via email or web services.

A toaster that can connect to the internet, allowing users to control it remotely or receive updates.

A phone that uses internet protocols to make calls over the internet instead of traditional telephone lines.

Circuit switching ensures guaranteed performance by allocating dedicated resources for each call, preventing sharing among multiple calls.

Content provider networks, such as Google, are private networks that connect their data centers to the Internet, often bypassing Tier 1 and regional ISPs to improve efficiency and reduce costs.

Nodal processing delay is the time taken to check bit errors and determine the output link for a packet, typically less than a millisecond.

It takes 120 seconds for the entire caravan of ten cars to be processed through the toll booth, as each car takes 12 seconds.

The cable headend is the facility where signals are received, processed, and transmitted to subscribers through the cable distribution network.

The Internet structure refers to the interconnected system of millions of access Internet Service Providers (ISPs) that connect users and networks globally.

Real Internet delays refer to the actual time taken for data packets to travel from the source to the destination across the Internet, including any delays caused by routers along the path.

The average end-to-end throughput is R_c bits/sec.

Common transmission rates for Ethernet include 10 Mbps, 100 Mbps, 1 Gbps, and 10 Gbps.

A peering link is a direct connection between two ISPs that allows them to exchange traffic without going through a third party, enhancing network performance and reducing latency.

An institutional router connects the local network to the Internet Service Provider (ISP), facilitating Internet access.

Link transmission rate, also known as link capacity or link bandwidth, is the rate at which data can be transmitted over a link, measured in bits per second (R).

Multiple ISPs create competition and diversity in services, enhancing the overall reliability and performance of Internet access.

A Wireless LAN operates within a building, typically covering a distance of about 100 feet.

A device that monitors energy usage and allows users to share their energy consumption data via Twitter.

In 1969.

The toll booth represents the bit transmission time, where each car (bit) takes a certain amount of time (12 seconds) to be serviced before continuing on the highway.

Asymmetric transmission allows for higher downstream rates (up to 30Mbps) compared to upstream rates (2Mbps), optimizing user experience for activities like streaming.

It helps to determine the average queueing delay and the overall performance of the network under varying load conditions.

POP stands for Point of Presence, which refers to an access point or location where different networks or communication devices connect to each other.

The Internet provides a programming interface to applications, including hooks that allow sending and receiving application programs to connect to the Internet.

A buffer is a waiting area in a network where packets are stored temporarily before being transmitted.

A Global Transit ISP is an Internet Service Provider that provides connectivity to the global Internet, allowing other ISPs to connect to it and access the broader network.

Protocols control the sending and receiving of messages over the Internet, ensuring proper communication between devices.

ISP stands for Internet Service Provider, which is a company that provides individuals and organizations access to the Internet.

Broadband refers to the capability of coaxial cable to support multiple channels for data transmission simultaneously.

A promiscuous network interface is a mode of operation for network devices that allows them to capture and read all packets on the network, regardless of their destination address.

Wireshark is a free packet-sniffer software used for capturing and analyzing network traffic, commonly utilized in network troubleshooting and educational labs.

A Regional Network is a network that connects multiple access networks and ISPs within a specific geographic area, providing broader connectivity and services.

A method of data transmission where packets are stored and forwarded at each router, requiring the entire packet to arrive before being transmitted on the next link.

Hybrid Fiber Coax, a type of broadband network that combines fiber optic and coaxial cable.

A protocol is a set of rules that defines the format and order of messages sent and received among network entities, as well as the actions taken on message transmission and receipt.

Access networks connect to each other through various interconnection methods and protocols, allowing for seamless data transmission across the Internet.

Packet loss occurs when a packet arriving at a full queue is dropped, meaning it cannot be transmitted due to the buffer's finite capacity.

The Caravan analogy illustrates how vehicles (or data packets) propagate through a network, using the example of cars traveling at a high speed and stopping at toll booths, highlighting the impact of service time on arrival at subsequent points.

A human protocol refers to the informal rules and conventions used in human communication, such as greetings and inquiries about time.

A technique that allows multiple channels to be transmitted simultaneously over a single communication medium by allocating different frequency bands to each channel.

The ISO/OSI reference model is a conceptual framework used to understand and implement networking protocols in seven layers, facilitating communication between different systems and applications.

A Tier 1 ISP is a commercial Internet Service Provider that has national and international coverage and is well-connected to the Internet, allowing it to provide services without needing to pay for access to other networks.

Circuit switching is commonly used in traditional telephone networks.

The steps involved in a Denial of Service (DoS) attack include selecting a target, breaking into hosts around the network (creating a botnet), and sending packets to the target from the compromised hosts.

The Internet comprises mobile networks, global ISPs, regional ISPs, home networks, and institutional networks.

Access ISPs must be interconnected so that any two hosts on different networks can send packets to each other, facilitating communication across the Internet.

Aggressive deployment of broadband access refers to the rapid expansion and availability of high-speed internet connections to a large number of users.

Bandwidth refers to the maximum rate of data transfer across a network path, measured in bits per second.

Cable Modem Termination System, which manages the data traffic between cable modems and the Internet.

'The Internet' is the correct phrase, as it refers to the global network of interconnected computers and systems.

One potential drawback is that a layer may duplicate functionality of a lower layer, such as error handling, which can lead to inefficiencies.

A protocol is a set of rules or standards that define how data is transmitted and received over a network.

Network security is the field that focuses on how bad actors can attack computer networks, how to defend against these attacks, and how to design architectures that are immune to attacks.

A packet is a smaller chunk of data created from an application message, typically of length L bits, for transmission over a network.

Security considerations are important in all layers of networking to ensure comprehensive protection against potential attacks and vulnerabilities.

Fiber optic cable is made of glass fibers that carry light pulses, with each pulse representing a bit of data.

The transmission rates for 802.11b/g (WiFi) are 11 Mbps and 54 Mbps, respectively.

Broadcast media such as shared Ethernet and wireless networks are particularly susceptible to packet sniffing due to their nature of allowing multiple devices to access the same communication channel.

Queueing delay is the time a packet spends waiting at the output link for transmission, which depends on the congestion level of the router.

Propagation delay (d prop) is the time it takes for a signal to travel from the sender to the receiver, calculated as d prop = d/s, where d is the length of the physical link and s is the propagation speed in the medium (approximately 2x10^8 m/sec).

Access networks provide the physical media for communication links, which can be wired or wireless.

The first operational packet-switching network conceived by the Advanced Research Projects Agency in 1967.

The one-hop transmission delay is calculated as L / R seconds, assuming zero propagation delay.

Packet switching is a method of data transmission where data is broken into packets and sent over a network, allowing multiple users to share the same communication channel efficiently.

End systems are devices such as computers, smartphones, and servers that are connected to the Internet and serve as sources or destinations for data.

Packet switching is great for bursty data, allows resource sharing, and is simpler as it does not require call setup.

A 1 Mb/s link indicates the total bandwidth available for data transmission, which can be divided among users based on their active usage, impacting overall network efficiency.

Instantaneous throughput is the rate at a given point in time.

It indicates that the average queueing delay is small, meaning the network can handle the packet arrival rate efficiently.

A network topology where multiple routers are interconnected, allowing for multiple paths for data to travel, enhancing reliability and performance.

Loss in the context of Internet performance refers to the situation where data packets fail to reach their destination, which can occur due to network congestion, errors, or other issues.

The structure of the Internet includes mobile networks, global ISPs, regional ISPs, home networks, and institutional networks.

An access network is a type of network that connects end users to the Internet, facilitating their access to services and resources.

Throughput refers to the end-to-end transmission rate of data across a network, specifically calculated as the minimum of the capacity of the bottleneck link (R_c), the source rate (R_s), or the shared rate (R/10) when multiple connections share a backbone link.

The Internet carries an extensive range of information resources and services, such as inter-linked hypertext documents and applications of the World Wide Web (WWW), infrastructure to support email, and peer-to-peer networks for file sharing and telephony.

An ISP, or Internet Service Provider, is a company that provides individuals and organizations access to the Internet and related services.

The session layer is responsible for synchronization, checkpointing, and recovery of data exchange between applications.

Internet Exchange Points (IXPs) are crucial for facilitating the exchange of Internet traffic between different networks, helping to improve connectivity and reduce latency.

Compromised hosts, often part of a botnet, are used to send packets to the target, overwhelming its resources and making them unavailable to legitimate users.

A worm is a type of self-replicating malware that infects a host by passively receiving an object that executes itself.

He introduced the concept of packet-switching in military networks.

Access networks are the networks that connect end users to the Internet, providing the necessary infrastructure for users to access online services and content.

The network core is made up of interconnected routers that form a network of networks.

A ticket is a document that confirms a passenger's purchase of a seat on a flight.

Packet switches, such as routers and switches, are responsible for forwarding packets, which are chunks of data, across the network.

A regional ISP provides internet access to a specific geographic area, while a home network connects devices within a household.

Packet switching is a method of data transmission where data is broken into packets that are sent independently over the network and reassembled at the destination.

Throughput is the rate (bits/time unit) at which bits are transferred between a sender and receiver.

Forwarding is the process of moving packets from one network interface to another within a router or switch, directing the data to its intended destination based on the routing table.

Link capacity R_s represents the maximum rate at which bits can be sent from the server, measured in bits per second.

The total time is 62 minutes, which includes 2 minutes for the caravan to push through the first toll booth and 60 minutes for the last car to propagate to the second toll booth.

The average time a packet spends waiting in a queue before being transmitted, influenced by the arrival rate of packets and the service rate of the network.

The Hong Kong Internet eXchange (HKIX) is a major Internet exchange point in Hong Kong that facilitates the exchange of Internet traffic between different networks.

Traffic intensity, which is the ratio of the average packet arrival rate (La) to the link bandwidth (R).

Connecting each access ISP to every other access ISP directly does not scale due to the quadratic increase in connections, represented as O(N^2).

A Tier-1 ISP is an internet service provider that can reach every other network on the internet without purchasing IP transit or paying for peering, typically providing backbone connectivity.

Layering is an explicit structure that allows for the identification and relationship of the pieces of a complex system, facilitating modularization and maintenance.

Packet loss occurs when arriving packets are dropped because there are no free buffers available in the router.

The average end-to-end throughput is R_s bits/sec.

The Internet is an infrastructure that provides services to applications such as web browsing, VoIP, email, games, e-commerce, and social networks.

Enterprise access networks are networking systems typically used in companies and universities to connect various devices and systems.

A device that modulates and demodulates signals for transmitting data over cable television lines, enabling internet access.

When the packet arrival rate temporarily exceeds the output link capacity, packets queue in the router buffers, leading to potential delays and loss.

An Access Network is a part of the telecommunications network that connects individual end-users to the broader Internet, allowing them to access online services.

Cars will arrive at the second toll booth before all cars are serviced at the first booth, as demonstrated by the scenario where the first car arrives at the second booth after 7 minutes while others are still being serviced.

A Host is a device that sends packets of data, taking application messages and breaking them into smaller chunks known as packets.

The Internet is a global system of interconnected computer networks that use the standard Internet protocol suite (TCP/IP) to link several billion devices worldwide.

The facility in a cable television system where signals are received, processed, and transmitted to subscribers.

Circuit switching is a method of communication where end-to-end resources are allocated and reserved for a call between the source and destination, ensuring dedicated resources and guaranteed performance.

In circuit switching, circuit segments remain idle if not used by a call, as there is no sharing of resources.

The presentation layer allows applications to interpret the meaning of data, handling tasks such as encryption, compression, and machine-specific conventions.

An IXP, or Internet Exchange Point, is a physical infrastructure that allows different Internet Service Providers to interconnect and exchange traffic between their networks.

DSL is a technology that allows for the transmission of voice and data over existing telephone lines, using different frequencies for each, enabling simultaneous use of the telephone network and internet.

Wide-area wireless access is provided by telecommunications (telco) operators and can cover distances of tens of kilometers, with transmission rates between 1 and 10 Mbps.

Hosts are end systems that run network applications and are connected to the Internet.

Total nodal delay is the sum of processing delay, queueing delay, transmission delay, and propagation delay.

The four sources of packet delay are propagation delay, nodal delay, processing delay, and queueing delay.

FDM divides the available bandwidth into frequency bands for simultaneous transmission, while TDM divides the time into slots for sequential transmission.

Propagation delay is the time it takes for a signal to travel from the sender to the receiver over the physical medium.

Packet switching is a method of data transmission where data is broken into packets and sent over a network, allowing for resource sharing and simpler communication without the need for a dedicated circuit.

Unguided media are types of physical media where signals propagate freely, such as in radio transmissions.

The network layer handles the routing of datagrams from the source to the destination, using IP and routing protocols.

Packet switching is a method of data transmission where data is broken into packets and sent over a network, allowing for efficient use of bandwidth.

A router connects multiple devices within a home network to the internet and manages traffic between them.

Delay refers to the time it takes for data to travel from the source to the destination in a network.

Packet-switching is a method where hosts break application-layer messages into packets, which are then forwarded through the network from router to router.

End systems are devices such as computers, smartphones, and servers that are connected to the Internet and serve as the source or destination of data.

Satellite radio links can offer speeds ranging from Kbps to 45 Mbps, with the possibility of multiple smaller channels.

Hypertext is a system of managing and linking text in a non-linear way, allowing for interactive navigation, conceptualized by Vannevar Bush in 1945 and expanded by Ted Nelson in the 1960s.

A wireless access point commonly supports speeds of 54 Mbps.

An enterprise network is a network that connects the various devices and systems within an organization to facilitate communication and data sharing.

A computer network protocol is a formal set of rules that govern the communication between devices in a network, ensuring data is transmitted accurately and efficiently.

A TCP connection is a reliable, ordered, and error-checked delivery of a stream of data between applications running on hosts communicating via an IP network.

RFC stands for Request for Comments, which is a series of memoranda describing methods, behaviors, investigations, or advances related to the operation of the Internet.

End-to-end throughput is calculated as the minimum of the capacity of the bottleneck link (R_c), the source rate (R_s), or the shared rate (R/10) in a scenario where 10 connections share a backbone link.

Queueing delay is the time a packet spends waiting in a queue before it can be transmitted on the output link.

Institutional access networks are the networks that provide internet connectivity to organizations such as schools and companies, often utilizing dedicated lines or shared connections.

ISO stands for the International Organization for Standardization, which develops and publishes international standards.

The Internet structure refers to its design as a collection of interconnected networks, allowing for communication and data exchange across various systems and services.

Time Division Multiplexing, a technique that allocates different time slots for multiple signals to share the same transmission medium.

A physical link is the actual medium that lies between the transmitter and receiver in a network.

The Internet is a global system of interconnected computer networks that use the Internet protocol suite (TCP/IP) to link devices worldwide.

The destination address in an arriving packet's header is crucial for determining the path the packet should take through the network, influencing both forwarding and routing decisions.

The transport layer is responsible for process-to-process data transfer, utilizing protocols like TCP and UDP.

An IXP, or Internet Exchange Point, is a physical infrastructure that allows different Internet service providers to connect and exchange traffic between their networks.

The initial step where passengers buy tickets for their flights.

Circuit switching is a method of communication where a dedicated communication path is established between two endpoints for the duration of the transmission.

The physical layer represents the transmission of bits 'on the wire' and is responsible for the physical connection between devices.

TCP/IP is a suite of communication protocols used for the Internet and similar networks, enabling devices to communicate over a network.

End systems are devices such as computers and smartphones that connect to the network and serve as the source or destination of data.

If more than 35 users are active simultaneously, it may lead to network congestion, increased delay, and potential packet loss, affecting overall performance.

Packet switching is a method of data transmission where data is broken into packets that are sent independently over the network and reassembled at the destination.

Layering in airline functionality refers to the organization of services where each layer implements its own actions while relying on the services of the layer below.

Throughput is the rate at which data is successfully transmitted over a network in a given amount of time.

The Internet consists of millions of private, public, academic, business, and government packet switched networks, linked by a broad array of electronic, wireless, and optical networking technologies.

An Access Network is a type of network that connects individual users to a larger network, such as the Internet, facilitating access to various services and resources.

Packet transmission delay is the time needed to transmit an L-bit packet into a link, calculated as L (bits) divided by R (bits/sec).

Malware is malicious software designed to infiltrate or damage a host system, often through the Internet.

Fiber optic cable offers high-speed point-to-point transmission rates (e.g., tens to hundreds of Gbps) and has a low error rate due to repeaters being spaced far apart and its immunity to electromagnetic noise.

When the arrival rate to a link exceeds its transmission rate, packets will queue up and wait to be transmitted, and they may be dropped if the buffer fills up.

Hosts refer to clients and servers within a network, where servers are often located in data centers.

ISP stands for Internet Service Provider, which is a company that provides individuals and organizations access to the internet.

Communication links refer to the physical mediums such as fiber, copper, radio, and satellite that connect devices in a network.

A botnet is a network of infected hosts that can be controlled remotely, often used for sending spam or launching DDoS attacks.

A local forwarding table is used by routers to decide how to forward incoming packets to the appropriate output link based on the destination address in the packet's header.

Public demonstration of ARPAnet, introduction of the first host-host protocol (NCP), and the first email program.

Circuit switching is a method of data transmission where a dedicated communication path is established between two users for the duration of their conversation, ensuring a constant data rate.

The typical downstream transmission rate for DSL is less than 24 Mbps, frequently around 10 Mbps.

A runway is a strip of land at an airport where aircraft take off and land.

The procedure where passengers hand over their luggage to the airline for transportation in the cargo hold.

Category 6 cable supports data rates of up to 10 Gbps for Ethernet connections.

The probability of more than 10 users being active at the same time is less than 0.0004, indicating that packet switching can efficiently accommodate many users.

SMTP (Simple Mail Transfer Protocol) is a protocol defined in 1982 for sending and receiving email over the Internet.

A trans-oceanic link refers to undersea cables that connect different continents, enabling long-distance data transmission across oceans.

The two main types of routing are static routing and dynamic routing.

Circuit switching is a method of communication where a dedicated communication path is established between two endpoints for the duration of the transmission.

Packet switching is a method of data transmission where data is broken into packets that are sent independently over the network and reassembled at the destination.

Sources of Packet Delay include factors like transmission delay, propagation delay, queuing delay, and processing delay that affect the time it takes for packets to travel across a network.

Coaxial cable consists of two concentric copper conductors that allow bidirectional communication and support broadband by providing multiple channels.

A bottleneck link is the point in a network where the capacity is limited, causing a restriction on the overall throughput of data transmission, often represented as R_c in scenarios with multiple connections.

Packet Switching is a method of data transmission where data is broken into packets that are sent over a network independently and can take different paths to the destination.

The Internet structure is a network of networks that connects end systems via access Internet Service Providers (ISPs), allowing any two hosts to send packets to each other.

A virus is a type of self-replicating malware that infects a host by receiving and executing an object, such as an email attachment.

Transmission delay (d trans) is the time taken to push all the packet's bits into the link, calculated as d trans = L/R, where L is the packet length in bits and R is the link bandwidth in bits per second.

3G and 4G are mobile communication technologies, with 4G often referred to as LTE, providing wireless access to the Internet.

Online social networks, such as Facebook, have significantly increased user engagement on the Internet, with Facebook approaching one billion users.

Shared access networks allow multiple users to share the same bandwidth, while dedicated access networks provide a specific bandwidth exclusively for one user or organization.

Guided media are types of physical media where signals propagate through solid media such as copper, fiber, or coaxial cables.

ISP stands for Internet Service Provider, which is a company that provides individuals and organizations access to the Internet.

The types of networks include global ISPs, regional ISPs, home networks, and institutional networks.

Twisted pair (TP) cable consists of two insulated copper wires and is commonly used in networking.

Disadvantages include the possibility of excessive congestion, leading to packet delay and loss, necessitating protocols for reliable data transfer and congestion control.

In packet switching, if each user is active only 10% of the time, it allows more users to share the network without overwhelming it, as not all users are active simultaneously.

A firewall protects the home network by controlling incoming and outgoing network traffic based on predetermined security rules.

'border1 - rt - fa5 - 1 - 0.gw.umass.edu' is a hostname that corresponds to a router in the network path, showing the specific route taken by the packet.

Routing is the process of selecting paths in a network along which to send network traffic.

The ongoing problem is how to provide circuit-like behavior, including bandwidth guarantees, in a packet-switched network, which remains unsolved.

The planned path that an aircraft follows during its flight from departure to arrival.

FTP (File Transfer Protocol) is a protocol defined in 1985 for transferring files over a network.

Wireless devices are gadgets that connect to the home network without physical cables, often using Wi-Fi technology.

A national or global ISP is an internet service provider that offers internet access on a large scale, covering extensive geographical areas.

A local or regional ISP is an internet service provider that offers internet access within a specific locality or region.

TCP stands for Transmission Control Protocol, which is a fundamental protocol for reliable data transmission over the Internet.

A wireless access network connects an end system to a router via a base station, also known as an access point.

A refrigerator that connects to the internet, enabling features like inventory tracking and remote temperature control.

Residential access networks are the connections that provide internet access to individual homes, typically using technologies like DSL, cable, or fiber optics.

The 'Internet stack' refers to the layers of the OSI model that are not explicitly included in the Internet protocol suite, meaning that certain services must be implemented at the application level if needed.

A mathematical study of waiting lines that shows the effectiveness of packet-switching.

The attackers, often referred to as 'bad guys,' target servers and network infrastructure to disrupt services.

Transmission delay is the time taken to push all the packet's bits onto the link.

Content provider networks are specialized networks operated by companies like Google, Microsoft, or Akamai to deliver services and content efficiently to end users.

DDoS attacks, or Distributed Denial of Service attacks, are attempts to make a network service unavailable by overwhelming it with traffic from multiple sources.

End-to-end delay is calculated as 2L / R, assuming zero propagation delay.

End systems are devices such as computers, smartphones, and servers that connect to the Internet and provide services to users.

ALOHA protocol is a pioneering satellite network developed in Hawaii in 1970, which laid the groundwork for wireless communication.

The early development of packet-switching principles.

The network core is a mesh of interconnected routers that forwards packets from one router to the next across links on the path from source to destination.

Circuit switching is a method of communication where a dedicated communication path is established between two endpoints for the duration of the transmission.

Wide-area radio links, like 3G cellular, generally provide speeds of a few Mbps.

Protocol layers are a hierarchical structure used in networking to separate different functions and responsibilities of communication protocols.

Network security encompasses measures and protocols designed to protect the integrity, confidentiality, and availability of computer networks.

End systems are devices like computers and smartphones that connect to the Internet to send and receive data.

The history of the Internet traces the development of networking technologies and protocols from early ARPANET to the modern global Internet.

Circuit switching is a method of communication where a dedicated communication path is established between two endpoints for the duration of the transmission.

The process where passengers exit the aircraft and retrieve their belongings after landing.

A datacenter network is a network designed to connect servers and storage systems within a datacenter for efficient data processing and storage.

The history of the Internet details its development from early research projects to the global network it is today, highlighting key milestones and technologies.

Denial of Service (DoS) is an attack where attackers make resources, such as servers or bandwidth, unavailable to legitimate traffic by overwhelming them with bogus traffic.

The IETF, or Internet Engineering Task Force, is an organization that develops and promotes voluntary Internet standards, particularly standards that comprise the Internet protocol suite.

Access ISPs (Internet Service Providers) are providers that connect end systems, such as residential, company, and university networks, to the Internet.

The Central Office is a facility where DSL signals are processed and routed to the Internet, serving as the connection point between the local telephone network and the broader internet.

Mobile access networks are wireless networks that allow devices to connect to the internet via cellular technology, enabling mobility for users.

The evolution of the Internet structure is driven by economics and national policies.

Routing is a global action that determines the source-destination paths taken by packets, utilizing routing algorithms to make these determinations.

Service providers like Google and Microsoft create their own networks to bypass the traditional Internet, offering instantaneous access to services such as search and email.

A global ISP (Internet Service Provider) provides internet access on a worldwide scale.

Cloud services, such as Amazon EC2, allow e-commerce, universities, and enterprises to run their services online, enhancing flexibility and scalability.

The propagation environment can affect radio signals through reflection, obstruction by objects, and interference.

A protocol is a set of rules or standards that define how data is transmitted and received over a network.

The link layer facilitates data transfer between neighboring network elements, employing technologies like Ethernet, 802.11 (WiFi), and PPP.

LAN radio links, such as WiFi, typically operate at speeds of 11 Mbps to 54 Mbps.

Access Technologies refer to the various methods and technologies used to connect end-user devices to the Internet or other networks.

Throughput is the rate at which data is successfully transmitted over a network in a given amount of time.

Protocol layers are hierarchical levels in network communication that define specific functions and responsibilities for data transmission.

Packet switching is a method of data transmission where data is broken into packets and sent independently over the network, allowing for efficient use of bandwidth.

Satellite radio links typically experience an end-to-end delay of about 270 milliseconds.

Static routing is a routing technique where routes are manually configured and do not change unless manually updated.

Network delay is the time taken for a packet of data to travel from the source to the destination across a network.

Protocol layers are a hierarchical structure in networking that organizes the functions of communication protocols, allowing for modular design and interoperability.

Network security involves measures taken to protect the integrity, confidentiality, and availability of computer networks and data from unauthorized access or attacks.

Throughput is the rate at which data is successfully transmitted over a network in a given amount of time.

A frame is a data packet at the link layer that includes the data payload and control information such as source and destination MAC addresses.

A method of communication where a dedicated communication path is established between two endpoints for the duration of the transmission.

The Internet is described as a 'network of networks,' where a small number of well-connected large networks form the core, supported by various regional and access ISPs.

It refers to a technique where the entire packet must arrive at a router before it can be transmitted to the next link.

Spyware is a type of malware that can record keystrokes, track websites visited, and upload collected information to a remote site.

DSLAM stands for Digital Subscriber Line Access Multiplexer, a device that connects multiple DSL lines to a high-speed internet backbone, enabling data transmission from users to the internet.

The application layer supports network applications such as FTP, SMTP, and HTTP.

The Internet is a global network of interconnected computers that communicate using standardized protocols.

The typical upstream transmission rate for DSL is less than 2.5 Mbps, often around 1 Mbps.

Routing algorithms are methods used to determine the optimal paths for packets to travel from source to destination across a network.

An institutional network refers to a network set up within an organization, such as a school or business, to connect its devices.

A '*' indicates that there was no response from a probe, meaning the packet was lost or the router did not reply.

Airplane routing involves the planned path that an aircraft follows during its flight.

The Internet is a global network of interconnected computers that communicate using standardized protocols.

Audio and video applications require bandwidth guarantees to ensure a consistent quality of service, which is a challenge in packet switching.

The phase in which an airplane accelerates down the runway and becomes airborne.

Layering in networking refers to the organization of network protocols into layers, each serving a specific function and allowing for modular design.

The network edge refers to the part of the network where end systems, such as computers and devices, connect to access networks, which provide the means to reach the core of the network.

The Concept of Network of Networks refers to the structure of the Internet, where multiple interconnected networks operate together to form a larger network.

TCP congestion control is a mechanism introduced in 1988 to manage network traffic and prevent congestion in TCP/IP networks.

Throughput is the rate at which data is successfully transmitted over a network in a given amount of time.

Protocol layers are levels in a networking architecture that define specific functions and responsibilities for data transmission and communication.

By the late 1990s, it was estimated that there were around 50 million hosts and over 100 million users on the Internet.

Networks under attack refer to systems that are targeted by malicious activities aimed at disrupting services or compromising data.

Smartphones and tablets have contributed to the rapid increase in the number of hosts on the Internet, reaching approximately 750 million since 2005.

Packet loss occurs when packets are dropped and not delivered to their destination, often due to buffer overflow when the memory is full.

Physical media refers to the medium through which signals propagate between transmitter and receiver pairs.

Transmission delay is calculated as L / R seconds, where L is the packet size in bits and R is the transmission rate in bits per second.

Bandwidth is the transmission rate that measures the amount of data that can be transmitted over a communication link in a given time.

Voice and data are transmitted over a dedicated line to the Central Office at different frequencies, allowing for simultaneous communication without interference.

Baggage check is the process of registering luggage with an airline for transport during a flight.

Time-sharing a single communication line among multiple users by assigning each user a specific time slot.

'ms' stands for milliseconds, a unit of time equal to one thousandth of a second, commonly used to measure latency in network communications.

Terrestrial microwave is a type of radio link that can support channels up to 45 Mbps.

End systems are devices like computers and smartphones that are connected to the Internet and serve as sources or destinations of data.

The Internet is a global network of interconnected computers that communicate using standardized protocols.

Air traffic control centers manage the safe and orderly flow of air traffic in the airspace.

Types of Physical Media in Networking include the various physical means through which data is transmitted, such as copper cables, fiber optics, and wireless signals.

ATM stands for Asynchronous Transfer Mode, a networking technology that switched fixed-length packets, serving as a precursor to modern networking techniques.

Delay in networks refers to the time it takes for a packet of data to travel from the source to the destination.

Network security encompasses measures and protocols designed to protect the integrity, confidentiality, and availability of computer networks and data.

The internetworking principles include minimalism, autonomy, best-effort service model, stateless routers, and decentralized control, shaping today's Internet architecture.

The area in an airport where passengers retrieve their checked luggage after a flight.

CSNET, BITNET, NSFNET, and Minitel are examples of national networks that emerged in the 1980s, contributing to the growth of the Internet.

A routing table is used by routers to store the routes to various network destinations and the next hop for each destination.

Protocol layers are a hierarchical structure that organizes the functions of network protocols to facilitate communication across networks.

Encapsulation is the process of wrapping data with protocol information at each layer of the network model, creating a message that can be transmitted over the network.

Frequency Division Multiplexing, a technique that divides the frequency spectrum into multiple channels to allow simultaneous transmission of multiple signals.

Forwarding, also known as switching, is a local action that moves arriving packets from a router's input link to the appropriate router output link based on the local forwarding table.

The Internet protocol stack is a five-layer model that supports network applications and data transfer, consisting of the application, transport, network, link, and physical layers.

Nodal delay (d nodal) is the total delay experienced at a node, calculated as d nodal = d proc + d queue + d trans + d prop, where d proc is processing delay, d queue is queueing delay, d trans is transmission delay, and d prop is propagation delay.

Radio is a physical medium where signals are carried in the electromagnetic spectrum without a physical wire, allowing for bidirectional communication.

Gates are designated areas in an airport where passengers board and exit the aircraft.

An Access Network is a home network that connects to/from a headend or central office, typically using technologies like cable or DSL modems.

A DSL modem splitter is a device that separates the voice and data signals on a DSL line, allowing both to be used simultaneously without interference.

Circuit switching is a communication method where a dedicated communication path is established between two endpoints for the duration of the transmission.

ARPAnet was the first operational packet-switching network and the predecessor of the modern Internet, decommissioned in the early 1990s.

Proprietary architectures refer to unique networking systems developed by companies, such as DECnet, SNA, and XNA in the late 1970s.

Circuit switching is a method of communication where a dedicated communication path is established between two endpoints for the duration of the transmission.

Wired Ethernet in home networks typically supports speeds of 100 Mbps.

A home network is a local area network that connects personal devices within a residential setting.

HTML (Hypertext Markup Language) and HTTP (Hypertext Transfer Protocol) were developed by Tim Berners-Lee.

Delay refers to the time it takes for a packet of data to travel from the source to the destination across the network.

In home networking, devices such as the cable or DSL modem, router, firewall, and wireless access point are often combined in a single box.

Delay refers to the time it takes for data to travel from source to destination, loss refers to packets that fail to reach their destination, and throughput is the rate at which data is successfully transmitted over the network.

The history of the Internet involves the development of various technologies and protocols that have enabled the global interconnection of computers, evolving from ARPANET to the modern Internet.

Backbone links were running at gigabits per second (Gbps) in the 1990s, indicating a significant increase in network capacity.

The physical layer is the first layer of the OSI model, responsible for the transmission and reception of raw bitstreams over a physical medium.

Traceroute is a network diagnostic tool used to track the path that a packet takes from one computer to another, measuring the time taken for each hop along the route.

ARPAnet had 15 operational nodes.

The Internet is a global network of interconnected computers that communicate using standardized protocols.

Category 5 cable supports data rates of 100 Mbps to 1 Gbps for Ethernet connections.

Circuit switching is a method of communication where a dedicated communication path or circuit is established for the duration of the transmission, often used for voice calls.

The designated areas in an airport where passengers board and disembark from aircraft.

Network performance refers to metrics such as loss, delay, and throughput that indicate the efficiency and speed of data transmission in a network.

Baggage claim is the process where passengers retrieve their checked luggage after a flight.

DNS (Domain Name System) is a system defined in 1983 for translating human-friendly domain names into IP addresses.

Network security involves measures and protocols designed to protect the integrity, confidentiality, and availability of computer networks and data.

The procedure through which passengers express dissatisfaction regarding their ticketing experience.

The history of Internet development traces the evolution of networking technologies and protocols from early research projects to the modern Internet.

Network security involves measures taken to protect data during transfer and to safeguard networks from unauthorized access and attacks.

The TCP/IP Layers are a set of protocols that govern the Internet, typically structured into four layers: Application, Transport, Internet, and Network Interface.

Encapsulation is the process of wrapping data with protocol information at each layer of the TCP/IP model to prepare it for transmission over a network.

Routing metrics are used to determine the best path for data transmission based on various factors such as distance, speed, and reliability.

The transport layer is responsible for end-to-end communication, ensuring complete data transfer and providing error correction and flow control.

End systems include devices like smartphones, PCs, servers, and wireless laptops.

Packet switching is a method of data transmission where data is broken into packets that are sent independently over the network and reassembled at the destination.

Ethernet is a networking technology developed in 1976 at Xerox PARC, which became a standard for local area networks (LANs).

Delay in networks refers to the time it takes for a packet of data to travel from the source to the destination.

In 1991, the National Science Foundation (NSF) lifted restrictions on commercial use of NSFnet, which was decommissioned in 1995.

The Internet is a global network of interconnected computers that communicate using standardized protocols, enabling the exchange of data and access to information.

Packet Switching is a method of data transmission where data is broken into packets and sent independently, while Circuit Switching establishes a dedicated communication path for the duration of the transmission.

Circuit switching is a method of communication where a dedicated communication path is established between two endpoints for the duration of the transmission.

The two types of satellite orbits mentioned are geosynchronous and low altitude.

Dynamic routing is a routing technique that automatically adjusts routes based on current network conditions.

In the late 1990s, network security became a critical focus as the Internet grew and more users engaged with online platforms.

Interior routing protocols operate within a single autonomous system, while exterior routing protocols operate between different autonomous systems.

The history of the Internet encompasses its development from early research projects to the global network we use today, including key milestones and technologies.

Cerf and Kahn are computer scientists known for their work in 1974 on the architecture for interconnecting networks, which is foundational to the Internet.

The IP address 128.119.240.254 represents the gateway (cs-gw) in the network path from gaia.cs.umass.edu, used as the first hop in the Traceroute measurement.

Packet switching is a method of data transmission where data is broken into packets and sent independently over the network, allowing for efficient use of resources.

NAT stands for Network Address Translation, and it allows multiple devices on a local network to share a single public IP address.

A mobile network is a type of network that allows for wireless communication and connectivity for mobile devices.

The Internet is a global network of interconnected computers that communicate using standardized protocols.

The growth of ARPAnet to 200 nodes by 1979 demonstrates the expanding network of interconnected computers, which was critical in the development of the Internet.

The history of the Internet involves its development from ARPANET in the 1960s to the global network we use today, including key milestones and technological advancements.

Mosaic was one of the first widely used web browsers, released in 1994, which later evolved into Netscape.

The late 1990s saw the commercialization of the Web and the emergence of 'killer apps' such as instant messaging and P2P file sharing.

The history of the Internet encompasses its development from early ARPANET to the modern global network, highlighting key technological advancements and milestones.

Between 1980 and 1990, there was a proliferation of new protocols and networks, significantly expanding Internet connectivity and functionality.

BGP is an exterior gateway protocol used to exchange routing information between different autonomous systems on the internet.

Packet switching is a method of data transmission where data is broken into packets and sent independently over the network.

Circuit switching is a communication method that establishes a dedicated communication path between two parties for the duration of the transmission.

Delay refers to the time it takes for a packet of data to travel from the source to the destination.

Network vulnerabilities are weaknesses in a network that can be exploited by attackers to gain unauthorized access or cause harm.

Service models define the services provided by the network to applications and users, detailing how data is transmitted and received.

Protocol layers are a set of hierarchical protocols that define how data is transmitted over a network, each layer serving a specific function.

Routing protocols determine how routers communicate with each other to exchange information about network reachability.

The term 'confederation of networks' refers to the interconnected systems of networks that collectively supported 100,000 hosts during the 1980s.

Networks under attack refer to scenarios where malicious actions are taken against network systems, compromising security and integrity, often leading to data breaches or service disruptions.

A datagram is a basic transfer unit associated with a packet-switched network, containing source and destination addresses and data.

Throughput is the rate at which data is successfully transmitted over a network, while a Bottleneck is a point in the network where the flow of data is restricted, leading to reduced throughput.

The phase in which an airplane descends and touches down on the runway at the destination airport.

A content provider network is a network that delivers digital content, such as videos or applications, to end users over the internet.

A router is a networking device that forwards data packets between computer networks, directing traffic and determining the best path for data transmission.

Protocol layers are a structured approach to network communication, where each layer has specific functions and interacts with the layers above and below it to facilitate data exchange.

An autonomous system is a collection of IP networks and routers under the control of a single organization that presents a common routing policy to the internet.

The history of the Internet encompasses its development from early networking concepts in the 1960s to the vast global network we use today, involving key technological advancements and protocols.

A switch is a device that connects devices within a local area network (LAN) and uses MAC addresses to forward data to the correct destination.