Computer Networks - Chapter 1 - Part 2
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Questions and Answers

What does an Access Point (AP) primarily do?

  • Relay packets between wireless computers and the Internet (correct)
  • Provide a wired connection to the internet
  • Prevent signal interference
  • Store data locally

    • Wired LANs typically operate at lower speeds than wireless LANs.

    False

    What is the standard for wireless LANs known as?

    IEEE 802.11

    In a wired LAN, devices typically connect through a _____.

    <p>switch</p> Signup and view all the answers

    What is the maximum speed that newer LANs can achieve?

    <p>10 Gbps</p> Signup and view all the answers

    VLANs are used to manage network traffic effectively.

    <p>True</p> Signup and view all the answers

    What is the purpose of a switch in a wired LAN?

    <p>To relay packets between connected computers.</p> Signup and view all the answers

    What happens when packets collide in the classic Ethernet?

    <p>Computers wait a random time and try again</p> Signup and view all the answers

    IEEE 802.3 is popularly known as _____.

    <p>Ethernet</p> Signup and view all the answers

    Match the following network terminologies with their descriptions:

    <p>Access Point = Relays packets in a wireless LAN Switched Ethernet = Connects multiple computers through point-to-point links VLAN = Divides a physical LAN into multiple logical networks Classic Ethernet = Used a linear cable for communication</p> Signup and view all the answers

    What is the operation mode called when a packet is transmitted and received by every machine on the network?

    <p>Broadcasting</p> Signup and view all the answers

    Multicasting allows transmission to every machine on the network.

    <p>False</p> Signup and view all the answers

    Name one common example of a Personal Area Network (PAN).

    <p>Bluetooth</p> Signup and view all the answers

    A network that connects computers and devices within a single building is known as a ______.

    <p>Local Area Network (LAN)</p> Signup and view all the answers

    Match the following types of networks to their descriptions:

    <p>PAN = Connects devices within a very short range, like Bluetooth. LAN = Operates within and nearby a single building. WAN = Covers a large geographic area, often multiple cities. Internetwork = Connection of multiple networks, like the Internet.</p> Signup and view all the answers

    Which technology is primarily used for wireless Personal Area Networks?

    <p>Bluetooth</p> Signup and view all the answers

    Wireless LANs can only be used in newly constructed buildings.

    <p>False</p> Signup and view all the answers

    What is the primary purpose of a Local Area Network (LAN)?

    <p>To connect personal computers and share resources.</p> Signup and view all the answers

    The concept where a master device communicates with slave devices in a PAN is known as the ______ paradigm.

    <p>master-slave</p> Signup and view all the answers

    What is an example of a large-scale network that connects multiple networks?

    <p>Internetwork</p> Signup and view all the answers

    What is a major advantage of wireless networking compared to wired networking?

    <p>More convenience and lower installation cost</p> Signup and view all the answers

    Wired networking is better at preventing unauthorized access compared to wireless networking.

    <p>True</p> Signup and view all the answers

    What challenge do home LANs face regarding user management?

    <p>They need to be easy to manage, dependable, and secure, especially for nontechnical users.</p> Signup and view all the answers

    A MAN (Metropolitan Area Network) typically covers a __________.

    <p>city</p> Signup and view all the answers

    What did cable television networks evolve into with the advent of the Internet?

    <p>Metropolitan Area Networks</p> Signup and view all the answers

    WiMAX is a standard for Wide Area Networks (WANs).

    <p>False</p> Signup and view all the answers

    Name one of the types of networks mentioned that can provide Internet connectivity through electric wires.

    <p>Power-line networks</p> Signup and view all the answers

    Which of the following is a feature of Wide Area Networks (WANs)?

    <p>They span large geographical areas.</p> Signup and view all the answers

    The rest of the network that connects hosts in a WAN is called the __________.

    <p>communication subnet</p> Signup and view all the answers

    Match the following network types with their corresponding descriptions:

    <p>LAN = Small area, like a home or office MAN = Covers a city WAN = Spans a large geographical area Power-line Networks = Use electric wiring for internet connectivity</p> Signup and view all the answers

    Which allocation method involves a single entity determining who goes next?

    <p>Centralized allocation</p> Signup and view all the answers

    Static allocation allows machines to transmit at any time based on demand.

    <p>False</p> Signup and view all the answers

    What is one key requirement for networked devices in home networks?

    <p>Ease of installation</p> Signup and view all the answers

    In a __________ channel allocation method, each machine decides when to transmit.

    <p>decentralized</p> Signup and view all the answers

    Match the home network requirements with their descriptions:

    <p>Ease of installation = Devices should work out of the box. Foolproof operation = Minimal user intervention required. Low price = Affordable for the average consumer. Gradual expansion = Able to start small and grow the network over time.</p> Signup and view all the answers

    What is a potential development in home networks mentioned?

    <p>All appliances will be networked to communicate with each other.</p> Signup and view all the answers

    Consumers are often tolerant of networked devices requiring lengthy setups.

    <p>False</p> Signup and view all the answers

    What is a common misconception about decentralized allocation methods?

    <p>That it leads to chaos.</p> Signup and view all the answers

    When a machine is not broadcasting during its time slot in a static allocation, it __________ channel capacity.

    <p>wastes</p> Signup and view all the answers

    What does not contribute to the success of home network devices?

    <p>Complex operation</p> Signup and view all the answers

    What is a characteristic of point-to-point links?

    <p>Connect individual pairs of machines</p> Signup and view all the answers

    Broadcast networks use a dedicated communication channel for each machine.

    <p>False</p> Signup and view all the answers

    What type of communication does unicasting refer to?

    <p>Point-to-point transmission between exactly one sender and one receiver</p> Signup and view all the answers

    In a broadcast network, packets sent by any machine are received by ______ machines.

    <p>all other</p> Signup and view all the answers

    Match the following types of network transmissions with their characteristics:

    <p>Unicast = Communication between one sender and one receiver Broadcast = Communication where packets are received by all machines Point-to-point = Connection between two specific machines Wireless = Broadcast transmission over a coverage area</p> Signup and view all the answers

    Which of the following describes the primary role of the address field in a packet?

    <p>To specify the intended recipient of the packet</p> Signup and view all the answers

    Wireless networks are an example of point-to-point transmission technology.

    <p>False</p> Signup and view all the answers

    What happens when a machine receives a packet that is not intended for it?

    <p>It ignores the packet.</p> Signup and view all the answers

    What is the purpose of a protocol in communication?

    <p>To define how communication should proceed</p> Signup and view all the answers

    Violating the protocol can make communication easier.

    <p>False</p> Signup and view all the answers

    What is a protocol stack?

    <p>A list of protocols used by a system, one protocol per layer.</p> Signup and view all the answers

    Each layer in a network architecture interacts with the layer _____ it and the layer _____ it.

    <p>above, below</p> Signup and view all the answers

    Match the layers with their corresponding roles in communication:

    <p>Layer 1 = Physical medium for communication Layer 2 = Data link and protocol mappings Layer 3 = Network and routing functions Layer 4 = Transport of data and reliability</p> Signup and view all the answers

    What defines the operations and services available between adjacent layers in network architecture?

    <p>Interface</p> Signup and view all the answers

    Different hosts in a network cannot use different implementations of the same protocol.

    <p>False</p> Signup and view all the answers

    What occurs when one layer communicates with another in a network?

    <p>It passes data and control information to the layer immediately below it.</p> Signup and view all the answers

    A specific collection of well-understood functions performed by each layer is required to maintain _____ interfaces.

    <p>clean</p> Signup and view all the answers

    What is the role of a subnet operator?

    <p>To connect customers and provide internet services</p> Signup and view all the answers

    Which analogy is used to explain multilayer communication?

    <p>Two philosophers speaking different languages</p> Signup and view all the answers

    Satellite networks are designed for point-to-point communication.

    <p>False</p> Signup and view all the answers

    What does the term 'internetwork' refer to?

    <p>A collection of interconnected networks.</p> Signup and view all the answers

    In cellular networks, the first generation was ______ and for voice only.

    <p>analog</p> Signup and view all the answers

    Match the following cellular network generations with their characteristics:

    <p>1G = Analog and voice only 2G = Digital and voice only 3G = Digital for both voice and data 4G = High-speed data and voice</p> Signup and view all the answers

    Which of the following is NOT a feature of the ISP network?

    <p>Allows customer communications only among themselves</p> Signup and view all the answers

    The forwarding algorithm determines how routers choose paths in a network.

    <p>False</p> Signup and view all the answers

    What is the typical data rate of cellular networks compared to wireless LANs?

    <p>1 Mbps for cellular networks, up to 100 Mbps for wireless LANs.</p> Signup and view all the answers

    The decision-making process for which path to use in a network is called a ______ algorithm.

    <p>routing</p> Signup and view all the answers

    What is the main function of the backbone network in a cellular system?

    <p>Connects base stations</p> Signup and view all the answers

    Which layer is responsible for breaking up messages into smaller packets?

    <p>Layer 3</p> Signup and view all the answers

    Layer 4 adds a trailer to the message before passing it to Layer 3.

    <p>False</p> Signup and view all the answers

    What is the primary purpose of a header added by Layer 4?

    <p>To identify the message and include control information.</p> Signup and view all the answers

    The process of ensuring a network operates correctly despite unreliable components is known as ______.

    <p>reliability</p> Signup and view all the answers

    Match the layer with its function:

    <p>Layer 1 = Physical transmission Layer 2 = Data link control Layer 3 = Routing packets Layer 4 = Message segmentation</p> Signup and view all the answers

    What does Layer 2 add to each piece of data before passing it on to Layer 1?

    <p>Both header and trailer</p> Signup and view all the answers

    Protocols and interfaces in different layers can affect each other directly.

    <p>False</p> Signup and view all the answers

    What type of information can the processes in each layer add that is not passed to the layer above?

    <p>Control information intended for peer processes.</p> Signup and view all the answers

    The abstraction that allows breaking down the design of a network into manageable problems is called ______.

    <p>peer process abstraction</p> Signup and view all the answers

    Which layer's protocol conceptualizes communication as being 'horizontal'?

    <p>Layer 4</p> Signup and view all the answers

    What are the primary components of a subnet in a WAN?

    <p>Transmission lines and switches</p> Signup and view all the answers

    All WANs are operated by a single entity.

    <p>False</p> Signup and view all the answers

    What is the commonly used term today for a switching element that forwards data between lines?

    <p>router</p> Signup and view all the answers

    A ________ is used to create a virtual link over the Internet between different offices.

    <p>VPN</p> Signup and view all the answers

    Match the following WAN components with their functions:

    <p>Transmission lines = Move bits between machines Switching element = Connects two or more transmission lines Router = Forwards data packets to the appropriate outgoing line VPN = Creates virtual links over the Internet</p> Signup and view all the answers

    What is a key advantage of using a VPN compared to a dedicated line?

    <p>Flexible reuse of resources</p> Signup and view all the answers

    Switching elements only connect individual computers in a subnet.

    <p>False</p> Signup and view all the answers

    Name two types of transmission lines that can be used in a subnet.

    <p>copper wire and optical fiber</p> Signup and view all the answers

    The separation of communication aspects from application aspects in networking simplifies overall ________ design.

    <p>network</p> Signup and view all the answers

    Which technology might a router connect to in a WAN environment?

    <p>Switched Ethernet</p> Signup and view all the answers

    What is an internetwork formed by?

    <p>Connecting different networks together</p> Signup and view all the answers

    A gateway operates only at the lowest layer of the protocol hierarchy.

    <p>False</p> Signup and view all the answers

    What device is commonly referred to as a gateway that switches packets at the network layer?

    <p>router</p> Signup and view all the answers

    An internet is formed when distinct networks are __________.

    <p>interconnected</p> Signup and view all the answers

    Match the following network layers with their description:

    <p>Application Layer = Interacts with software applications Transport Layer = Manages end-to-end communication Network Layer = Routes packets between networks Data Link Layer = Handles node-to-node data transfer</p> Signup and view all the answers

    Which statement best describes the rules of thumb for identifying an internetwork?

    <p>Different organizations managing their own parts</p> Signup and view all the answers

    Layer n protocols involve conversations between layers on different machines.

    <p>True</p> Signup and view all the answers

    What is the main consequence of using lower-level gateways?

    <p>Inability to connect different kinds of networks</p> Signup and view all the answers

    Network software is now highly __________.

    <p>structured</p> Signup and view all the answers

    Which of the following is not a characteristic of a protocol hierarchy?

    <p>All networks have the same number of layers</p> Signup and view all the answers

    What is the primary mechanism used to recover the correct message from possibly incorrect bits?

    <p>Error correction codes</p> Signup and view all the answers

    Routing is used to identify multiple paths between a source and destination in a network.

    <p>True</p> Signup and view all the answers

    What term describes the division of the overall problem to hide implementation details in networking?

    <p>protocol layering</p> Signup and view all the answers

    The issue of keeping a fast sender from overwhelming a slow receiver is known as __________.

    <p>flow control</p> Signup and view all the answers

    Match the following design issues with their descriptions:

    <p>Routing = Finding a working path through the network Flow Control = Managing data transfer between fast and slow hosts Congestion = Overloading of the network due to high demand Statistical Multiplexing = Dynamic sharing of network resources based on demand</p> Signup and view all the answers

    Which of the following statements is true regarding error detection?

    <p>It adds redundant information to help identify errors.</p> Signup and view all the answers

    All communication channels preserve the order of messages sent on them.

    <p>False</p> Signup and view all the answers

    What term is used for sharing network bandwidth dynamically based on short-term needs?

    <p>statistical multiplexing</p> Signup and view all the answers

    The overall topic of connecting different networks and managing their limitations is called __________.

    <p>internetworking</p> Signup and view all the answers

    What happens when a network experiences congestion?

    <p>Data overflow occurs, causing delays.</p> Signup and view all the answers

    Which type of service preserves message boundaries?

    <p>Message sequence</p> Signup and view all the answers

    Unreliable connectionless service is also known as datagram service.

    <p>True</p> Signup and view all the answers

    What type of service allows the sender to transmit a message without establishing a connection?

    <p>Unreliable connectionless service</p> Signup and view all the answers

    In a ________ service, the sender receives confirmation of message delivery.

    <p>Reliable</p> Signup and view all the answers

    Match the following communication services with their characteristics:

    <p>Reliable connection-oriented = Acknowledges receipt of messages Unreliable connectionless = No acknowledgment required Acknowledged datagram = Like sending a registered letter Request-reply = Client sends a request and waits for a server response</p> Signup and view all the answers

    What kind of applications usually prefer unreliable communication methods?

    <p>Voice over IP</p> Signup and view all the answers

    All applications require a reliable communication service for effective performance.

    <p>False</p> Signup and view all the answers

    What is a common example of a service that provides acknowledged delivery?

    <p>Text messaging</p> Signup and view all the answers

    The service that allows a sender to request information and receive a reply is known as ________ service.

    <p>Request-reply</p> Signup and view all the answers

    Which of the following statements about datagram service is true?

    <p>It is suitable for real-time applications.</p> Signup and view all the answers

    What type of service is modeled after the telephone system?

    <p>Connection-oriented service</p> Signup and view all the answers

    Connectionless service guarantees that messages will arrive in the order they are sent.

    <p>False</p> Signup and view all the answers

    What is the primary mechanism to ensure confidentiality in network communications?

    <p>Cryptography</p> Signup and view all the answers

    In __________ service, acknowledgments are required to ensure messages are received correctly.

    <p>reliable connection-oriented</p> Signup and view all the answers

    Match the following types of network services with their characteristics:

    <p>Connection-oriented = Establishes a connection prior to data transfer Connectionless = Sends messages without establishing a fixed connection Reliable = Ensures data is not lost during transmission Unreliable = May lose data without notification</p> Signup and view all the answers

    Which of the following is a characteristic of connection-oriented service?

    <p>There is a consistent order of message delivery</p> Signup and view all the answers

    Connectionless service is modeled after the telephone system.

    <p>False</p> Signup and view all the answers

    What is meant by the term 'quality of service' in networking?

    <p>Mechanisms that reconcile competing demands for real-time delivery and high throughput.</p> Signup and view all the answers

    __________ switching allows the onward transmission of a message to start before it is fully received.

    <p>Cut-through</p> Signup and view all the answers

    Match the following threats with their corresponding defensive mechanisms:

    <p>Eavesdropping = Confidentiality mechanisms Impersonation = Authentication mechanisms Message alteration = Integrity mechanisms</p> Signup and view all the answers

    What is the primary function of service primitives?

    <p>To access and manage services provided by user processes</p> Signup and view all the answers

    The primitives for connection-oriented service are identical to those for connectionless service.

    <p>False</p> Signup and view all the answers

    What system call indicates that a server is prepared to accept incoming connections?

    <p>LISTEN</p> Signup and view all the answers

    The client process executes CONNECT to establish a connection with the ______.

    <p>server</p> Signup and view all the answers

    What happens to the client process after it executes the CONNECT call?

    <p>It is suspended until a connection is established.</p> Signup and view all the answers

    Match the following service primitives with their actions:

    <p>LISTEN = Prepares the server for incoming connections CONNECT = Requests to establish a connection ACKNOWLEDGE = Confirms receipt of a packet DISCONNECT = Ends the connection between client and server</p> Signup and view all the answers

    A call to the operating system to send packets is an example of a service primitive.

    <p>True</p> Signup and view all the answers

    What is typically required as a parameter when a client wants to connect to a server using the CONNECT call?

    <p>server's address</p> Signup and view all the answers

    What is the purpose of the ACCEPT call in the client-server communication process?

    <p>To establish a connection with the client process</p> Signup and view all the answers

    The DISCONNECT call is a non-blocking call that does not suspend the client process.

    <p>False</p> Signup and view all the answers

    What analogy is used to explain the client-server communication process?

    <p>A customer calling a company’s customer service manager.</p> Signup and view all the answers

    The arrival of the request packet at the server machine __________ the server so it can handle the request.

    <p>unblocks</p> Signup and view all the answers

    Match the following operations with their correct order in the client-server communication protocol:

    <ol> <li>LISTEN = Wait for client connection</li> <li>ACCEPT = Establish connection</li> <li>RECEIVE = Prepare to accept request</li> <li>SEND = Transmit the request</li> </ol> Signup and view all the answers

    Why are additional packets often required in connection-oriented communication?

    <p>To handle potential packet loss and errors</p> Signup and view all the answers

    Services and protocols are considered the same concept in network communication.

    <p>False</p> Signup and view all the answers

    What occurs when the server successfully executes the SEND operation?

    <p>The server returns an answer to the client.</p> Signup and view all the answers

    When the client has additional requests, it can __________ them after inspecting the answer.

    <p>make</p> Signup and view all the answers

    Which of the following accurately describes a service in the context of client-server communication?

    <p>A set of operations provided by a layer to its upper layer</p> Signup and view all the answers

    What is the main purpose of the transport layer in networking?

    <p>To carry data from the source to the destination</p> Signup and view all the answers

    An error-free transport channel is completely impossible to achieve.

    <p>True</p> Signup and view all the answers

    Name one service provided by the session layer.

    <p>Dialog control</p> Signup and view all the answers

    The transport layer primarily ensures that messages are delivered in the correct __________.

    <p>order</p> Signup and view all the answers

    Match the following OSI layers with their primary function:

    <p>Transport Layer = End-to-end data delivery Session Layer = Session management and control Presentation Layer = Data representation and encoding Application Layer = User-specific protocols</p> Signup and view all the answers

    Which protocol is widely used for transferring web pages?

    <p>HTTP</p> Signup and view all the answers

    The TCP/IP reference model was developed after the OSI model.

    <p>False</p> Signup and view all the answers

    What does TCP stand for in TCP/IP?

    <p>Transmission Control Protocol</p> Signup and view all the answers

    The primary design goal of the architecture underlying the TCP/IP model was to connect multiple __________ in a seamless way.

    <p>networks</p> Signup and view all the answers

    Which layer manages the abstract data structures and ensures compatible data representation?

    <p>Presentation Layer</p> Signup and view all the answers

    What is the main function of the internet layer in the TCP/IP model?

    <p>To allow independent travel of packets to their destination.</p> Signup and view all the answers

    The transport layer of the TCP/IP model is designed for connectionless communication.

    <p>False</p> Signup and view all the answers

    What is the primary concern of the physical layer?

    <p>Transmitting raw bits accurately</p> Signup and view all the answers

    What is the purpose of the IP protocol within the internet layer?

    <p>To deliver IP packets to their specified destinations.</p> Signup and view all the answers

    The network layer is responsible for detecting and correcting transmission errors.

    <p>False</p> Signup and view all the answers

    The _____ provides a reliable connection-oriented protocol for data transmission.

    <p>TCP</p> Signup and view all the answers

    What is the function of the data link layer?

    <p>To transform a raw transmission facility into an error-free line.</p> Signup and view all the answers

    Match the following TCP/IP protocols with their primary characteristics:

    <p>TCP = Reliable, connection-oriented protocol UDP = Unreliable, connectionless protocol IP = Delivers packets to their destinations ICMP = Helps in network error handling</p> Signup and view all the answers

    In the transport layer, data is split into smaller units called __________.

    <p>segments</p> Signup and view all the answers

    Why was a flexible architecture necessary for the DoD's network?

    <p>To accommodate various applications with different requirements.</p> Signup and view all the answers

    The link layer is a standard layer in the TCP/IP model.

    <p>False</p> Signup and view all the answers

    Match the following layers with their primary functions:

    <p>Physical Layer = Transmits raw bits over a medium Data Link Layer = Transmits data frames and manages errors Network Layer = Routes packets and manages congestion Transport Layer = Ensures data integrity across segments</p> Signup and view all the answers

    Which layer would handle packet routing issues between two different networks?

    <p>Network Layer</p> Signup and view all the answers

    What is the primary role of the ICMP protocol?

    <p>To assist in error handling and diagnostics in the network.</p> Signup and view all the answers

    The internet layer corresponds roughly to the _____ network layer in the OSI model.

    <p>OSI</p> Signup and view all the answers

    The transport layer isolates upper layers from hardware changes.

    <p>True</p> Signup and view all the answers

    What happens to packets traveling through the internet layer?

    <p>They may be rearranged by higher layers if out of order.</p> Signup and view all the answers

    What mechanism may be needed in the data link layer to prevent data overflow between a fast transmitter and a slow receiver?

    <p>Traffic regulation mechanism</p> Signup and view all the answers

    The __________ layer deals with the mechanical, electrical, and timing interfaces of a network.

    <p>physical</p> Signup and view all the answers

    What is a primary concern of the network layer when handling packet transfers?

    <p>Routing packets and managing different addressing schemes</p> Signup and view all the answers

    What distinguishes a service from a protocol?

    <p>A service relates to the interface between layers.</p> Signup and view all the answers

    Protocols can be changed without affecting the service they provide to users.

    <p>True</p> Signup and view all the answers

    How many layers does the OSI model consist of?

    <p>seven</p> Signup and view all the answers

    A service is akin to an abstract data type or an object in an _________ language.

    <p>object-oriented</p> Signup and view all the answers

    Which model is primarily used for TCP/IP protocols?

    <p>TCP/IP Model</p> Signup and view all the answers

    Match the following OSI model principles with their descriptions:

    <p>Different abstraction is needed = A layer should be created where a different abstraction is needed. Well-defined function = Each layer should perform a well-defined function. Standardized protocols = The function of each layer should be chosen with an eye toward defining internationally standardized protocols. Minimize information flow = The layer boundaries should be chosen to minimize the information flow across the interfaces.</p> Signup and view all the answers

    Which protocol is used for delivering real-time media such as voice or movies?

    <p>RTP</p> Signup and view all the answers

    The OSI model specifies the exact services and protocols to be used in each layer.

    <p>False</p> Signup and view all the answers

    The OSI model includes session and presentation layers, which are also essential for most applications.

    <p>False</p> Signup and view all the answers

    Name one of the higher-level protocols included in the application layer of the TCP/IP model.

    <p>DNS, HTTP, SMTP, FTP, or TELNET</p> Signup and view all the answers

    What is a key concept that any network designer should understand well regarding services and protocols?

    <p>The decoupling of services from protocols.</p> Signup and view all the answers

    The primary purpose of the __________ layer in the TCP/IP model is to ensure reliable delivery of data.

    <p>transport</p> Signup and view all the answers

    The model developed for international standardization of protocols is called the ______ model.

    <p>OSI</p> Signup and view all the answers

    Which of the following statements regarding the historical context of protocols is true?

    <p>Older protocols did not distinguish between service and protocol.</p> Signup and view all the answers

    Match the following layers of the TCP/IP model with their descriptions:

    <p>Physical = Transmits bits across different types of media Link = Sends finite-length messages between connected computers Network = Combines multiple links into internetworks Application = Contains programs that use the network</p> Signup and view all the answers

    Which of the following is NOT a feature of the TCP/IP model?

    <p>Includes session and presentation layers</p> Signup and view all the answers

    Interconnecting networks to form internetworks is primarily the task of the transport layer.

    <p>False</p> Signup and view all the answers

    What is the main responsibility of the link layer in the TCP/IP model?

    <p>Sending finite-length messages between directly connected computers</p> Signup and view all the answers

    The protocol used for fetching pages on the World Wide Web is __________.

    <p>HTTP</p> Signup and view all the answers

    Which of the following statements best describes the relationship between the OSI and TCP/IP models?

    <p>They are both based on the concept of a stack of independent protocols.</p> Signup and view all the answers

    What is one reason why older protocol implementations like TELNET are still in use today?

    <p>They are free and easily available</p> Signup and view all the answers

    The Internet is the only type of network mentioned in the text.

    <p>False</p> Signup and view all the answers

    What does IEEE 802.11 represent in the context of networking?

    <p>The standard for wireless LANs</p> Signup and view all the answers

    TELNET was originally designed for a ______ character per second mechanical Teletype terminal.

    <p>ten</p> Signup and view all the answers

    Match the following network technologies with their primary purpose:

    <p>Internet = Global computer networking Mobile phone network = Wireless communication over distances IEEE 802.11 = Wireless LAN standard RFID = Identifying and tracking objects</p> Signup and view all the answers

    Which type of network technology extends the reach of networks to include physical objects?

    <p>RFID</p> Signup and view all the answers

    What are the three central concepts of the OSI model?

    <p>Services, Interfaces, Protocols</p> Signup and view all the answers

    The TCP/IP model clearly distinguishes between services, interfaces, and protocols.

    <p>False</p> Signup and view all the answers

    What is one major benefit of layered protocols in network design?

    <p>They allow for replacement of protocols without affecting higher layer software.</p> Signup and view all the answers

    In the OSI model, a layer's _____ specifies what parameters are expected and what results will occur.

    <p>interface</p> Signup and view all the answers

    Match the following OSI model concepts with their definitions:

    <p>Services = What a layer does Interfaces = How to access a layer Protocols = How a layer works internally</p> Signup and view all the answers

    Which of the following statements is true regarding the development of the OSI and TCP/IP models?

    <p>The OSI model was created before the protocols, while TCP/IP protocols were established first.</p> Signup and view all the answers

    The OSI model was designed based on extensive experience with existing technologies.

    <p>False</p> Signup and view all the answers

    What was one challenge faced by the OSI model regarding its data link layer?

    <p>It originally dealt only with point-to-point networks and needed adaptations for broadcast networks.</p> Signup and view all the answers

    The ability to change protocols transparently is a primary purpose of _____ protocols.

    <p>layered</p> Signup and view all the answers

    What was the main concern during the design of the OSI model regarding uses of the protocols?

    <p>Each country would have one government-run network</p> Signup and view all the answers

    What is a major problem associated with the OSI model?

    <p>Complexity and inefficiency in operation</p> Signup and view all the answers

    The TCP/IP model effectively distinguishes between services, interfaces, and protocols.

    <p>False</p> Signup and view all the answers

    What initial impression did people associate with OSI due to its early implementations?

    <p>Poor quality</p> Signup and view all the answers

    The TCP/IP model does not clearly distinguish the physical layer from the ______ layer.

    <p>data link</p> Signup and view all the answers

    Match the following layers or components with their descriptions:

    <p>IP = Protocol for routing packets across networks TCP = Protocol ensuring reliable transmission of data Physical layer = Concerns transmission characteristics Data link layer = Responsible for frame delivery and error detection</p> Signup and view all the answers

    What was a significant advantage of the early implementations of TCP/IP?

    <p>Users found it easy to implement and free</p> Signup and view all the answers

    The idea that OSI was supported by government agencies positively influenced its adoption.

    <p>False</p> Signup and view all the answers

    Name one function that reappears in each layer of the OSI model.

    <p>Error control</p> Signup and view all the answers

    In the TCP/IP model, trying to describe protocols like Bluetooth is ______.

    <p>impossible</p> Signup and view all the answers

    What was a consequence of the large user community of TCP/IP?

    <p>Increased innovation and improvement</p> Signup and view all the answers

    What is a major difference between the OSI model and the TCP/IP model?

    <p>The OSI model supports connection-oriented communication only in the transport layer.</p> Signup and view all the answers

    Both the OSI and TCP/IP models have the same number of layers.

    <p>False</p> Signup and view all the answers

    What are the two layers that the OSI model has that are nearly empty?

    <p>Session and Presentation</p> Signup and view all the answers

    The TCP/IP model supports connectionless communication in the ______ layer.

    <p>network</p> Signup and view all the answers

    Match the following reasons to their respective issues with the OSI model:

    <p>Bad timing = Competing protocols in use Bad technology = Flawed model complexity Bad implementations = Lack of initial offerings Bad politics = Political choice of layer numbers</p> Signup and view all the answers

    What is David Clark's theory regarding the establishment of standards?

    <p>It should be written during the active phase of research.</p> Signup and view all the answers

    The OSI model was established after significant corporate investment had already been made in competing protocols.

    <p>True</p> Signup and view all the answers

    What was one of the criticisms against the choice of layers in the OSI model?

    <p>Political rather than technical reasons</p> Signup and view all the answers

    The OSI model is often considered overly complex due to its extensive _____ definitions and protocols.

    <p>service</p> Signup and view all the answers

    What aspect of the OSI model complicates its practical implementation?

    <p>Contains empty layers</p> Signup and view all the answers

    Study Notes

    Transmission Technology

    • Two main types: broadcast links and point-to-point links.
    • Point-to-point links connect pairs of machines, transmitting data in packets potentially through intermediate machines.
    • Unicasting refers to point-to-point transmission with one sender and one receiver.
    • Broadcast networks allow all machines to share a communication channel; each packet includes an address field to identify the intended recipient.
    • Wireless networks exemplify broadcast links, where communication is based on proximity and shared channels.
    • Broadcasting can send packets to all machines, while multicasting targets a specific subset.

    Network Scale

    • Networks can be classified based on scale: Personal Area Networks (PANs), Local Area Networks (LANs), Metropolitan Area Networks (MANs), and Wide Area Networks (WANs).
    • PANs cater to a single individual, e.g., Bluetooth connections among devices.
    • LANs typically exist within a single building, facilitating resource sharing and information exchange; enterprise networks are the commercial counterpart.
    • Wireless LANs, operating under IEEE 802.11 (WiFi), use radio modems and access points for communication.
    • Wired LANs use copper wires or optical fibers, providing superior performance in speed, delay, and error rates compared to wireless.
    • MANs connect broader areas, such as cities; initially wired for cable TV, they now encompass Internet services via infrastructure changes.
    • WANs span large geographical areas, connecting numerous branch offices, typically comprising leased lines from telecommunications companies and switching elements (routers).

    Personal Area Networks (PANs)

    • Bluetooth technology connects devices (e.g., computer peripherals) wirelessly, simplifying user interactions.
    • PANs can communicate over short ranges using various technologies, including RFID for smartcards.

    Local Area Networks (LANs)

    • LANs facilitate resource sharing among computers within a home or office.
    • Wireless LANs are increasingly popular and convenient for installation in various settings.
    • Wired LANs can achieve speeds ranging from 100 Mbps to 10 Gbps, relying mainly on Ethernet (IEEE 802.3).
    • VLANs allow logical separation of networks within the same physical system, enhancing organizational management.
    • Modern home networks are evolving, with the potential for all appliances to connect seamlessly to the Internet.

    Metropolitan Area Networks (MANs)

    • MANs typically cover city areas and include cable TV networks evolved to provide Internet services.
    • High-speed wireless access has led to new MAN standards such as WiMAX (IEEE 802.16).

    Wide Area Networks (WANs)

    • WANs connect different geographical locations, often managed by separate entities.
    • Comprised of transmission lines and switching elements, WANs enable communication across substantial distances.
    • Hosts and the subnet in a WAN are usually owned and operated by different parties, clarifying responsibility for network components.

    Future Challenges and Opportunities

    • Home network devices must be user-friendly, secure, and competitively priced to attract consumers.
    • As smart home technology grows, maintaining low operational complexity and enhancing security will be vital for user acceptance.
    • The integration of existing infrastructure, like power lines for data transmission, presents additional opportunities for network expansion.### WAN Characteristics
    • Routers connect diverse networking technologies, like switched Ethernet within offices and SONET links for long-distance transmissions.
    • Many Wide Area Networks (WANs) operate as internetworks, combining multiple networks.
    • Subnets can connect individual computers or entire Local Area Networks (LANs).

    Virtual Private Networks (VPNs)

    • VPNs allow offices to connect over the Internet as virtual links, offering flexibility but reducing control over resources.
    • Adding offices to a VPN is simpler than dedicated lines.

    Internet Service Providers (ISPs)

    • A subnet may be managed by a third-party network service provider, connecting various customers and networks.
    • ISPs provide customers with Internet connectivity, enabling them to access other networks.

    Routing Algorithms

    • Communication between routers not sharing a direct connection occurs indirectly through other routers.
    • Routing algorithms determine the paths for data transfer, while forwarding algorithms decide packet handling.

    Wireless WAN Technologies

    • Satellite networks use antennas for bidirectional data exchanges, primarily leveraging broadcast properties.
    • Cellular networks are classified into generations, evolving from analog to digital and now capable of voice and data transmission.

    Defining Internetworks

    • Internetworks consist of interconnected networks, which may differ in hardware and software.
    • Connecting distinct networks creates an internetwork, often involving a LAN and a WAN.

    Role of Gateways

    • Gateways connect different networks and translate data across varying hardware and software platforms.
    • Routers typically operate at the network layer, facilitating packet switching.

    Network Software Structure

    • Modern networks utilize structured software layers for design simplification; each layer provides specific services to higher levels.
    • Protocols establish rules for communication between peers, akin to social etiquette.

    Layering Concept

    • Each layering protocol allows for modular design, where different implementations can coexist without affecting the overall network functionality.
    • Each layer transmits data to the next lower layer until it reaches the physical medium.

    Design Considerations for Layers

    • Reliability mechanisms incorporate error detection and correction to ensure accurate data transmission.
    • Routing provides alternative paths when parts of the network fail, increasing robustness.
    • Addressing mechanisms identify message origins and destinations, while size constraints lead to message segmentation and reassembly strategies.
    • Scalability ensures that network designs remain effective as they grow larger and more complex.### Resource Allocation in Networks
    • Networks allocate resources based on the capacity of transmission lines to ensure service to hosts.
    • Mechanisms are needed to prevent one host from interfering with another's bandwidth.
    • Statistical multiplexing shares bandwidth dynamically according to demand rather than fixed allocations.
    • Flow control prevents fast senders from overwhelming slow receivers, often using feedback mechanisms.
    • Congestion occurs when network demand exceeds capacity, requiring computers to reduce traffic.
    • Real-time delivery is critical for applications like live video, which adds complexity to bandwidth management.
    • Quality of Service (QoS) mechanisms balance competing demands for real-time delivery and high throughput.

    Network Security Concepts

    • Networks face threats such as eavesdropping, requiring mechanisms for confidentiality.
    • Authentication mechanisms verify identities, crucial for banking and preventing impersonation.
    • Integrity mechanisms protect data from unauthorized alterations during transmission.
    • Cryptography underlies confidentiality, authentication, and integrity in network communications.

    Connection-Oriented vs. Connectionless Service

    • Connection-oriented service mirrors telephone systems; requires establishing a connection before data transmission.

    • Data is sent in an ordered manner, preserving the sequence.

    • Negotiations on parameters and resource allocation can occur during connection setup.

    • Circuit refers to a connection with allocated resources, akin to a fixed bandwidth in a phone call.

    • Connectionless service reflects postal systems where each message routes individually with full addressing.

    • Messages at the network layer are termed packets; can employ store-and-forward or cut-through switching.

    • Sequence of data delivery can be disrupted, unlike in connection-oriented services.

    Reliability in Network Services

    • Reliable services confirm message receipt through acknowledgments, essential for accurate data transfer like file transfers.

    • Two variations exist:

      • Message sequences preserve distinct message boundaries.
      • Byte streams treat data as a continuous flow without message boundaries.

    • Real-time applications (e.g., VoIP) may prioritize timely delivery over reliability, accepting minor errors.

    • Unreliable connectionless services, termed datagram services, allow for easier transmission without connection setup.

    • Acknowledged datagram services provide a reliability layer without full connection establishment, akin to registered mail.

    • Request-reply service enables a query-response model, widely used in client-server architectures for swift communication.

    Coexistence of Communication Types

    • Understanding the preference for unreliable communication stems from:
      • Potential unavailability of reliable communication in certain layers (e.g., Ethernet).
      • Acceptable delays for reliable services may hinder real-time applications.
    • Both reliable and unreliable communication protocols coexist to meet varied application needs.

    Service Primitives

    • A service is specified by a set of primitives (operations) for user processes to access it.
    • Primitives trigger actions or report on actions between peer entities.
    • When protocols are in the OS, primitives are typically system calls that shift control to kernel mode to send packets.
    • Primitives differ between connection-oriented and connectionless services.
    • Example primitives for a reliable byte stream are similar to the Berkeley socket interface.
    • In a client-server environment, the server uses LISTEN to accept connections; it blocks until a connection is requested.
    • The client uses CONNECT, specifying the server's address to establish a connection; it then waits for a response.
    • The server unblocks upon receiving a connection request, executes ACCEPT to confirm the connection, and sends a response.
    • After the client and server are connected, the server uses RECEIVE to accept requests, and the client uses SEND to transmit.
    • DISCONNECT is used by the client to terminate the connection, which also requires acknowledgment from the server.
    • Connection-oriented protocols are chosen to ensure reliable data delivery in real-world scenarios.

    Relationship of Services to Protocols

    • Services comprise primitives provided by layers to upper layers, while protocols define message formats exchanged by peer entities.
    • Protocol changes do not impact user-visible services, ensuring a clear distinction between the two concepts.
    • Services can be likened to abstract data types, defining operations without detailing implementation.
    • Protocols focus on how services are realized through message exchanges between systems.
    • Older protocols often collapsed service and protocol distinctions, revealing a design flaw that modern designers avoid.

    Reference Models

    • The OSI and TCP/IP reference models illustrate common network architectures.
    • OSI model emphasizes standardization of communication protocols, while TCP/IP model is practical but less formal.

    OSI Reference Model

    • Consists of seven layers each serving unique functions, not specifying exact protocols but requiring clear demarcation of roles.
    • Key principles include creating layers for different abstractions, well-defined functions, and minimal information flow between layers.

    Physical Layer

    • Handles the transmission of raw bits and ensures they are received accurately.
    • Addresses electrical signals, timing, and transmission mediums.
    • Transforms raw transmission into reliable data, masking undetected errors.
    • Utilizes data frames for transmission and manages traffic regulation and medium access control.

    Network Layer

    • Manages packet routing and addresses congestion along with service quality parameters.
    • Facilitates communication across different network protocols and standards.

    Transport Layer

    • Accepts data, segments it, and ensures it arrives correctly.
    • Provides different types of services such as error-free channels and broadcasting.

    Session Layer

    • Manages sessions allowing users to establish communication, includes dialog control and synchronization.

    Presentation Layer

    • Focuses on data interchange formats, defining how different internal representations communicate.

    Application Layer

    • Contains user-facing protocols like HTTP for web communication and protocols for other applications like file transfer and email.

    TCP/IP Reference Model

    • Developed from ARPANET protocols, it emphasizes seamless connectivity across different networks.
    • Designed to remain functional despite failures in subnet hardware and adaptable to varied application requirements.
    • Describes interface needs for transmission links, not operating as a true layer.

    Internet Layer

    • Facilitates packet injection into networks, allowing for independent travel and possible out-of-order delivery.
    • Functions similarly to a postal system, where messages may take different routes to a destination but arrive accurately.### Internet Layer
    • Letters travel through international mail gateways, though users are unaware of this process.
    • Each country has unique stamps, envelope sizes, and delivery rules, which are also hidden from users.
    • The Internet Protocol (IP) is the official packet format and protocol, accompanied by the Internet Control Message Protocol (ICMP).
    • The primary function of the Internet layer is to route IP packets to their intended destinations.
    • Packet routing and congestion management are vital concerns, although IP struggles with congestion avoidance.

    Transport Layer

    • Sits above the Internet layer in the TCP/IP model, enabling communication between source and destination hosts.
    • Two main protocols:
      • TCP (Transmission Control Protocol) ensures reliable, connection-oriented communication, segmenting byte streams into messages for delivery without error.
      • UDP (User Datagram Protocol) allows connectionless communication for applications requiring fast delivery without error correction, suitable for live transmissions like audio or video.

    Application Layer

    • Lacks dedicated session or presentation layers as applications handle these functions as needed.
    • Protocols in this layer include TELNET (virtual terminal), FTP (file transfer), SMTP (email), and others such as DNS (domain name resolution), HTTP (web page requests), and RTP (real-time media delivery).

    Reference Model in Context

    • Combines aspects of the OSI and TCP/IP models, highlighting the utility of the TCP/IP protocols.
    • The model consists of five layers: Physical, Link, Network, Transport, and Application, each serving distinct functions.
    • The physical layer focuses on transmitting bits across various media, while the link layer manages communication between directly connected computers.
    • The network layer combines multiple links into internetworks, with IP as the primary protocol.
    • The transport layer enhances delivery guarantees, notably through TCP.

    OSI vs. TCP/IP Models

    • Both models are stack-based and provide end-to-end services, but differ in structure and functionality.
    • OSI has seven layers, while TCP/IP has four, with distinctions in connection-oriented (TCP) versus connectionless (UDP) communication.
    • OSI explicitly differentiates services, interfaces, and protocols, contrary to TCP/IP's less clear categorization.

    Critique of OSI Model

    • Criticized for poor timing and complexity, leading to inefficiencies and challenges in implementation.
    • Seven layers seen as more political than technical; session and presentation layers often underutilized.
    • Addressing, flow control, and error control redundantly handled across multiple layers.

    Critique of TCP/IP Model

    • Lack of distinction between services, interfaces, and protocols limits application to new technologies.
    • The link layer conflates with data link and physical functions, failing to separate distinct roles in layered architecture.
    • Many implemented protocols are ad hoc, leading to inefficiencies and outdated design, such as TELNET’s graphical limitations.

    Example Networks

    • Overview of various networks like the Internet, mobile phone networks, IEEE 802.11 (wireless LAN), and RFID/sensor networks.
    • Highlights the diversity in goals, scales, and technologies within computer networking.

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    Description

    This quiz focuses on the technical aspects of network design, specifically examining the different types of transmission technologies used in computer networks. Key concepts include broadcast links and point-to-point links, along with considerations around scale. Test your knowledge of these foundational principles in networking.

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