Sdp9 From The Photos

When a UDP segment arrives at a host, the operating system (OS) uses the destination port number to direct the segment to the appropriate socket. The destination port number is a unique identifier that specifies which application or service on the host should receive the incoming segment. The source port number and source IP address are not used by the OS for this purpose. Therefore, the correct answer is the destination port number.

The checksum field in nmap provides simple error detection. A checksum is a value calculated from a data packet to detect errors during transmission. It is used to ensure the integrity of the data by comparing the calculated checksum with the received checksum. If they match, it indicates that the data was transmitted without errors. Therefore, the checksum field in nmap serves as a means of error detection.

Channel partitioning refers to dividing the available communication channel into separate time slots or frequency bands. This technique ensures that transmitting nodes get the same amount of bandwidth, as each node is allocated a specific time slot or frequency band for communication. Channel partitioning also eliminates collisions, as each node operates in its designated slot or band, preventing interference with other nodes. Additionally, channel partitioning does not involve a master node, meaning that all nodes have equal control over the channel. Therefore, all the characteristics mentioned in the options are true for channel partitioning.

FTP (File Transfer Protocol) is built on a client-server architecture. In this architecture, the client initiates a connection with the server and sends requests for file transfers. The server, which is always online, responds to these requests by providing access to its file system and allowing the client to upload or download files. This client-server model allows for efficient and secure file transfers, as the server manages the resources and controls access to files while the client interacts with the server to perform the desired actions.

The correct answer is Network Layer. The Network Layer is responsible for routing and forwarding data packets across different networks. It chooses the datagram approach to switching, which means that it breaks the data into small packets and sends them individually across the network. This approach allows for efficient and flexible routing of packets, as each packet can take a different path to reach its destination.

Global Routing algorithm computes the least-cost path between source and destination using complete, global knowledge about the network. This means that it takes into account the entire network topology and all available information about the network, such as link costs and congestion levels, to determine the best route. It considers the network as a whole and makes decisions based on the overall network state, rather than just local information. This allows it to find the most efficient path from the source to the destination, considering all possible options.

Telnet is the correct answer because it is a network protocol that allows a user to establish a remote connection to another site and then pass keystrokes from their local host to the remote host. Telnet provides a virtual terminal interface, enabling users to access and control remote computers as if they were directly connected to them. This makes it possible to execute commands, run programs, and perform various tasks on a remote machine from a local computer.

The TCP segment does indeed have a field in its header for RcvWindow. This field is used to specify the size of the receive window, which is the amount of data that the sender can transmit before receiving an acknowledgment. The RcvWindow field allows for flow control in TCP, ensuring that the sender does not overwhelm the receiver with too much data at once.

The correct answer is "it consisted of many interconnected networks." This explanation is supported by the fact that the Internet was originally developed as a network of interconnected computers and networks, allowing for communication and data sharing between different systems. This interconnected nature of the Internet is what eventually led to its widespread adoption and global reach. The other options provided in the question do not accurately reflect the true reason for the Internet's name.

A socket is a software interface that allows communication between a computer program and the network. It enables the program to send and receive messages over the network. Therefore, the statement that the process that sends and receives messages through a software interface is called a socket is true.

Pipelining in networking requires all of the mentioned options. It involves transmitting multiple packets before receiving acknowledgements, which helps in improving efficiency and reducing latency. Unique sequence numbers for each in-transit packet are necessary to ensure reliable delivery and maintain order. Sender-side buffering of unacknowledged packets is also essential to handle the flow of data and prevent congestion. Therefore, all of these options are required for effective pipelining in networking.

Nmap is a popular network scanning tool used to perform port scans over a range of ports at a target host. It helps in identifying open ports and services running on those ports, which can be useful for network administrators to ensure the security of their systems. By scanning a range of ports, Nmap can provide information about potential vulnerabilities and weaknesses that could be exploited by attackers. It is an essential tool for network reconnaissance and security testing purposes.

The transport layer is the correct answer because it is the layer that lies between the network layer and the application layer. The transport layer is responsible for the reliable transmission of data between two hosts and provides services such as segmentation, flow control, and error recovery. It ensures that data is delivered in the correct order and without errors, making it an essential layer in the network communication process.

The header of a datagram in IPv4 can have a variable length ranging from 20 to 60 bytes. This is because the header contains various fields such as the source and destination IP addresses, protocol information, and options. The minimum length of the header is 20 bytes, which includes the mandatory fields. However, additional options and extensions can increase the length up to a maximum of 60 bytes.

The given IP address, 93.44.123.184, falls under Class A of IP addresses. In Class A, the first octet ranges from 1 to 126, and the remaining three octets can vary. The given IP address starts with 93, which is within the range of 1 to 126, indicating that it belongs to Class A.

An IPv4 datagram can encapsulate data from several higher-level protocols such as UDP, ICMP, IGMP, and TCP protocols. This means that when using IPv4, the data can be transmitted using any of these protocols depending on the specific requirements of the application. TCP protocols are commonly used for reliable and ordered transmission of data, making them suitable for applications such as web browsing, file transfer, and email.

In a TCP connection, there is a separate connection established for each file transfer. Since there are 5 files being transferred from server A to client B, there will be 5 separate TCP connections established. Additionally, there will be an extra TCP connection for the initial session setup. Therefore, the total number of TCP connections between A and B is 6.

The physical layer is responsible for all of the mentioned tasks, including line coding, channel coding, and modulation. Line coding involves converting digital data into a specific format for transmission over a physical medium. Channel coding adds redundancy to the transmitted data to ensure error detection and correction. Modulation involves converting the digital signals into analog signals suitable for transmission over the physical medium. Therefore, all these tasks fall under the responsibility of the physical layer.

The correct answer is that the current Internet is unable to guarantee minimum throughput or maximum latency for a given connection. This means that the Internet cannot ensure that a certain level of data transfer speed or delay will be maintained consistently during voice and video transmissions. This lack of guarantee can result in poor quality and interruptions in the transmission of high-quality, interactive voice and video over the Internet.

SMTP stands for Simple Mail Transfer Protocol. It is a communication protocol used to transfer email messages from one mail server to another. It is specifically designed for this purpose and ensures the reliable and efficient delivery of email messages across different servers. SMTP is not involved in transferring messages from a mail server to a user agent, nor does it define the format of message headers. Therefore, the correct answer is "to transfer messages from one mail server to another".

The correct answer is "the destination port number." When a UDP segment arrives at a host, the operating system (OS) uses the destination port number to direct the segment to the appropriate socket. The destination port number is a part of the UDP header and helps in identifying the specific application or process that should receive the incoming data. The source port number is used by the sending host to identify the application or process on its end, but it is not used by the OS to direct the segment to the appropriate socket. The source IP address is used for routing the segment to the correct host but not for directing it to the appropriate socket.

UDP (User Datagram Protocol) does not have a regulated send rate, as it does not provide any congestion control mechanisms. It also does not maintain a connection state at the server, as it is a connectionless protocol. Additionally, UDP does not require a three-way handshake for connection establishment, unlike TCP (Transmission Control Protocol). Therefore, the correct answer is "none of the above".

A data center is a facility that houses a large number of hosts, such as servers, storage devices, and networking equipment. It is designed to provide a secure and controlled environment for these hosts, ensuring their optimal performance and availability. By consolidating multiple hosts in a single location, a data center can create a powerful virtual server infrastructure that can handle high volumes of data processing and storage. Therefore, the statement "The housing a large number of hosts is often used to create a powerful virtual server" aligns with the concept of a data center.

E-mail is the correct answer because it meets the requirements of no data loss, elastic throughput, and not being time sensitive. E-mail messages can be sent and received without any loss of data, and the throughput can be adjusted based on the network capacity. Additionally, e-mails are not time sensitive as they can be delivered and read at any time, unlike real-time audio/video or text messaging. Games may require real-time interaction and can be time sensitive, making them unsuitable for the given requirements.

HTTP persistent connection allows multiple objects to be sent over a single TCP connection between a client and a server. This means that after the initial request and response, subsequent requests and responses can be sent without the need to establish a new TCP connection each time. This helps to reduce the overhead of establishing and tearing down connections, improving the efficiency and performance of the communication between the client and server.

At the application layer, data is divided into smaller units called messages. These messages are then passed down to the lower layers for further processing and transmission. Therefore, the correct answer for the given question is "message".

The statement "Twisted-pair copper wire is no longer present in computer networks" is false. Twisted-pair copper wire is still widely used in computer networks for Ethernet connections. It is a common type of cable that consists of pairs of insulated copper wires twisted together to reduce electromagnetic interference. This type of cable is known for its reliability and cost-effectiveness, making it a popular choice for networking purposes.

The stop-and-wait protocol is highly inefficient when there is a large distance between source and destination and the transmission rate is high because it involves sending one packet at a time and waiting for an acknowledgment before sending the next packet. In a high transmission rate scenario, the time taken for the acknowledgment to reach the source becomes significant due to the large distance, resulting in a significant delay in the overall transmission process. This inefficiency can be mitigated by using other protocols like the sliding window protocol, which allows for the transmission of multiple packets before receiving an acknowledgment.

Streams are not needed in a UDP server because UDP (User Datagram Protocol) is a connectionless protocol that does not guarantee the delivery of packets or the order in which they are received. Unlike TCP (Transmission Control Protocol), UDP does not establish a connection with the client, so there is no need for continuous data streams. UDP servers simply receive and process individual datagrams as they arrive.

When a server receives a SYN segment, it generates a SYNACK with an initial sequence number that is a hash of the IP addresses and port numbers in the SYN segment, as well as other factors. This approach, known as SYN cookies, helps prevent certain types of denial-of-service (DoS) attacks, such as SYN flood attacks. By using a hash of the IP addresses and port numbers, the server can verify the legitimacy of the connection request without storing any additional state information. This allows the server to conserve resources and handle a larger number of connection requests efficiently.

The FTP client contacts the FTP server at port 21 using TCP. FTP (File Transfer Protocol) is a standard network protocol used for transferring files between a client and a server on a computer network. Port 21 is the default port for FTP connections, and it is used for establishing the initial connection between the client and the server. TCP (Transmission Control Protocol) is the protocol used for reliable and ordered delivery of data packets over a network connection.

The given IP address, 158.0.147.85, can be converted to binary by converting each octet separately. The first octet, 158, is equal to 10011110 in binary. The second octet, 0, is equal to 00000000 in binary. The third octet, 147, is equal to 10010011 in binary. And the fourth octet, 85, is equal to 01010101 in binary. Therefore, the binary representation of the IP address 158.0.147.85 is 10011110.00000000.10010011.01010101.

The Traceroute tool relies on the use of IP (Internet Protocol) and TCP (Transmission Control Protocol) protocols to function properly. ICMP (Internet Control Message Protocol) is not essential for the existence of Traceroute, as it is used for diagnostic and error reporting purposes rather than the actual functioning of the tool. Therefore, the correct answer is "I and III only."

Host B will send acknowledgements to host A even if it does not have any data to send. This is because TCP requires acknowledgements to be sent for every segment received, regardless of whether or not there is data to piggyback the acknowledgement on.

Bit stuffing is a technique used in data communication to avoid confusing data bits with control bits. It involves adding extra bits to the data stream to ensure that certain patterns, which may be misinterpreted as control bits, do not occur naturally. By inserting additional bits, the sender can ensure that the receiver can correctly distinguish between data and control bits, enhancing the reliability of the communication.

A browser generates header lines as a function of the browser type and version, the user configuration of the browser, and whether the browser has a cached version of the requested object. All of these factors contribute to the generation of header lines by the browser.

The given IP address, 160.23.244.224, falls under Class B. In Class B, the first two octets are used to identify the network, while the remaining two octets are used to identify the host. In this case, the first octet is 160, which falls within the range of 128-191, indicating a Class B network.

The transfer of an HTML file from one host to another is considered loss-intolerant because any loss or corruption of the file during the transfer could result in a broken or incomplete webpage. Additionally, it is time-insensitive because the speed of the transfer does not affect the functionality or integrity of the HTML file.

The dynamic host configuration protocol (DHCP) allows a host to be assigned an IP address automatically. DHCP is a network management protocol that dynamically assigns IP addresses to devices on a network. It eliminates the need for manual IP address configuration, as the DHCP server automatically assigns and manages IP addresses for devices connected to the network. This simplifies network administration and ensures efficient allocation of IP addresses.

A channel partitioning protocol refers to a method of dividing a communication channel among multiple transmitting nodes. In this case, the given answer "all of the above" is correct. This implies that all the characteristics mentioned in the question are true for a channel partitioning protocol. Firstly, there is no master node, meaning that there is no central authority controlling the channel. Secondly, this protocol ensures that there are no collisions, where two or more nodes transmit data simultaneously and interfere with each other. Lastly, all transmitting nodes receive an equal amount of bandwidth, ensuring fairness in the allocation of resources.

When the version field of the IPv4 header indicates that the machine is using a different version of IPv4 than expected, the datagram is rejected. This means that the receiving machine does not process or forward the datagram, as it is not compatible with the expected version of IPv4.

The data link layer enhances the data with extra data that allows the receiver to synchronize with the sender. This extra data includes control information such as sequence numbers, acknowledgments, and error detection codes. By including this additional information, the receiver can accurately receive and interpret the transmitted data, ensuring that both the sender and receiver are synchronized and can effectively communicate with each other.

An elastic application refers to a software program or system that can dynamically allocate and deallocate resources based on demand. It can scale up or down its resource usage to efficiently handle varying workloads. In the context of email, an elastic application would be able to adapt to changing email traffic, allocating more resources during peak times and reducing resources during low traffic periods. This allows for optimal resource utilization and ensures that the email system remains responsive and efficient regardless of the workload.

False. In an HTTP Web server using persistent connections, the server does not spawn a separate process for each client. Instead, it maintains a pool of worker threads or processes that handle multiple client connections concurrently. Each client connection is assigned a unique socket, but the server port number remains the same for all connections.

Queuing delay refers to the delay experienced by a packet when it waits in a queue to be transmitted onto the link. This delay occurs when there are other packets already in the queue, and the packet has to wait for its turn to be transmitted. It is a result of congestion or limited resources in the network, causing packets to wait in a queue before they can be transmitted.

The correct answer is 5. When the router receives the 4096-byte datagram from node A, it will need to fragment it into smaller packets to fit the MTUs of the subnetworks it is connecting. The largest MTU is 2048 bytes, so the router will need to divide the datagram into two fragments of 2048 bytes each. However, the next largest MTU is 1556 bytes, so the second fragment will need to be further divided into two fragments of 1556 bytes and 492 bytes. Therefore, the router will process a total of 5 IP fragments.

Dividing a network into smaller portions is known as subnetting. Subnetting allows for better management and organization of network resources, as well as improved security and performance. By creating subnets, it becomes easier to allocate IP addresses and control network traffic within specific segments. Subnetting is achieved by using a subnet mask, which determines the network and host portions of an IP address.

The correct answer is "message" because in the application layer of the OSI model, data is referred to as a message. This layer is responsible for interacting with the end user and generating or receiving data that needs to be transmitted over the network. The data is then encapsulated into segments, frames, or datagrams at lower layers of the OSI model for transmission. However, at the application layer, the data is simply referred to as a message.

The correct answer indicates that the server is using HTTP/1.1 and that everything is OK. This is because the status line in an HTTP response message provides information about the status of the request. In this case, the status line indicates that the server is using the HTTP/1.1 protocol version and that the request was successful, with no errors or issues.

When TCP probes for additional bandwidth, rate increases are additive, which means that the rate at which data is transmitted is gradually increased by adding a fixed amount of data. On the other hand, rate decreases are multiplicative, meaning that the rate at which data is transmitted is reduced by multiplying it by a fixed factor. This approach helps maintain network stability by gradually increasing the data rate and quickly reducing it when necessary.

Authentication is the process of verifying the identity of a sender or receiver on a network. This involves confirming that the individual or device claiming to be a certain user or system is indeed who they say they are. It is important for security purposes to ensure that unauthorized users cannot gain access to sensitive information or perform malicious activities. By verifying identities, network administrators can control access to resources and ensure that only authorized users are granted permission to perform certain actions.

Fast retransmit is a mechanism used by TCP to quickly retransmit a lost segment without waiting for the retransmission timer to expire. It is triggered when the sender receives three duplicate acknowledgments (ACKs) for the same segment. This indicates that the receiver has received subsequent segments correctly but is still missing the one being acknowledged. Therefore, the sender assumes that the segment was lost and immediately retransmits it to avoid unnecessary delays in the data transmission.

When an Ethernet adapter receives a frame that is addressed to a different adapter, it simply discards the frame without sending an error message to the network layer. This is because Ethernet operates at the data link layer, and it is the responsibility of the network layer to handle addressing and routing. The adapter does not need to notify the network layer about the discarded frame as it is not relevant to its operation.

Host B will not send acknowledgements to host A because host B cannot piggyback the acknowledgement on data. This statement is false. In a TCP connection, host B is expected to send acknowledgements to host A to confirm the successful receipt of data. Piggybacking the acknowledgement on data is a common practice in TCP to optimize network efficiency. However, if host B has no data to send to host A, it can still send a standalone acknowledgement packet without any data.

The correct answer is "Sever; server". In the context of computer networks, a cookie is a small piece of data that is created by the server and sent to the client's web browser. The client's web browser then stores the cookie and sends it back to the server with subsequent requests. Therefore, the cookie is made by the server (sever) and eaten (used) by the server.

The statement is false because the acknowledgement number in a TCP segment represents the next expected sequence number, not the sequence number of the last received segment. In this case, since host A sends host B a segment with sequence number 38, the acknowledgement number should be 39, indicating that host B expects the next segment to have a sequence number of 39. Therefore, the correct answer is false.

The purpose of a presentation service is to encode, transmit, and translate data from one machine-specific format to another. This means that it is responsible for converting data into a format that can be easily understood and displayed by different devices or systems. This service ensures that data can be effectively communicated and shared across various platforms and technologies.

The dynamic host configuration protocol (DHCP) allows a host to be assigned an IP address automatically. DHCP is a network protocol that enables a server to assign IP addresses to network devices dynamically. It eliminates the need for manual IP address configuration, making it easier to manage and maintain large networks. With DHCP, hosts can obtain IP addresses, subnet masks, default gateways, and other network configuration parameters automatically, simplifying the process of connecting devices to a network.

The correct answer is "sent from one host to several hosts simultaneously." Link communication refers to the transmission of data between multiple hosts, where one host sends information to multiple hosts at the same time. This type of communication allows for efficient sharing of information and can be seen in various network scenarios such as broadcasting or multicasting.

SMTP (Simple Mail Transfer Protocol) is the standard protocol used for sending email messages between servers. It operates on TCP port 25 by default. Therefore, the correct answer is 25.

Ethernet (IEEE 802.3) started as a de facto standard, meaning it was widely adopted and used in practice before being officially recognized as a de jure standard. This means that Ethernet was initially developed and implemented by various companies and organizations without any formal standardization process. However, due to its success and widespread adoption, it eventually became a recognized and formalized standard by the appropriate standards organizations.

The responsibility of recording Internet routers of IPv4, that handles datagram, lies with the "Record Route" option. This option allows the source host to record the IP addresses of the routers that the datagram passes through on its way to the destination. This information can be useful for troubleshooting network issues and analyzing the path taken by the datagram.

In computer networking, the transport layer is responsible for breaking down the data into smaller units called segments. These segments contain the necessary information to ensure reliable delivery of the data. The transport layer adds headers to the segments, including source and destination port numbers, to facilitate the communication between the sender and the receiver. Therefore, the correct answer is "segment."

The HTTP response message consists of an initial status line, followed by six header lines, and then the entity body. The initial status line provides information about the status of the request, such as the HTTP version, status code, and status message. The header lines contain additional information about the response, such as content type, content length, and server information. Finally, the entity body contains the actual content of the response, such as HTML, text, or binary data.

The FDDI protocol is based on the token ring protocol. FDDI, which stands for Fiber Distributed Data Interface, is a standard for transmitting data on optical fiber cables. It uses a token passing mechanism, similar to the token ring protocol, to control access to the network. In a token ring network, a token is passed from one device to another, allowing only the device holding the token to transmit data. This ensures fair and efficient access to the network. Therefore, the FDDI protocol is based on the token ring protocol.

Multicast communication refers to the process of sending data from one host to multiple hosts simultaneously. Unlike unicast communication, where data is sent from one host to another host, multicast allows for the efficient distribution of data to multiple recipients. This is commonly used in applications such as video streaming, online gaming, and audio conferencing, where the same data needs to be transmitted to multiple users at the same time.

The Date: header in the HTTP response message does not indicate when the object in the response was last modified. Instead, the Last-Modified header is used for this purpose. The Date: header indicates the date and time when the response message was generated by the server.

Routing paths are calculated by routing algorithms. These algorithms analyze various factors such as network topology, available bandwidth, and congestion levels to determine the most efficient path for data packets to travel from the source to the destination. By considering these factors, routing algorithms can dynamically adjust the paths based on network conditions, ensuring optimal data transmission and minimizing delays or packet loss.

In asynchronous serial communication, the physical layer provides both start and stop signaling and flow control. Start and stop signaling is used to indicate the beginning and end of a data frame, ensuring that the receiver can properly interpret the data. Flow control is used to manage the rate of data transmission between the sender and receiver, preventing data loss or overflow. Therefore, the correct answer is both start & stop signaling and flow control.

An Application Programming Interface (API) is a set of rules and protocols that govern the communication between software programs. In the context of the given question, an API ensures that the sending program follows the necessary rules for the Internet to successfully deliver data to the destination program. It provides a standardized way for different software components to interact and exchange information, enabling seamless communication and data transfer over the Internet.

To deliver a message to the correct application program running on a host, the port address must be consulted. The port address is a numerical identifier that specifies a particular process or service on a host. It helps in directing the message to the correct application program, ensuring that it reaches the intended destination. The IP address identifies the host, while the MAC address is used for identifying the network interface card. Therefore, the port address is the most relevant in this context.

Circuit-switched networks establish a dedicated communication path between the sender and receiver for the duration of the conversation. This ensures a constant and reliable bit rate, which is important for voice conversations where late arrival of a voice sample can cause unpleasant sound effects. Packet-switched networks, on the other hand, divide the data into small packets that can be sent over different paths, leading to potential delays and variations in bit rate. Message-switched and space-switched networks are not commonly used for voice communication and may not provide the necessary constant bit rate required for high-quality voice conversations.

The Time to Live (TTL) field in the IP header is designed to prevent a packet from remaining indefinitely in a routing loop. It is a counter that is decremented by each router the packet passes through. If the TTL reaches zero, the packet is discarded, preventing it from continuously circulating in the network. This mechanism ensures that packets do not consume excessive network resources and helps to avoid routing loops.

Standards developed by the Internet Engineering Task Force (IETF) are extensively critiqued and modified by individuals, without requiring them to have special membership status. This means that anyone can participate in the development of these standards, providing their expertise and insights to improve them. Unlike traditional standards organizations, the IETF allows for a more open and inclusive process, encouraging collaboration and input from a wide range of individuals. This helps to ensure that the standards are thoroughly reviewed and refined before they are finalized and implemented.

The correct answer is "None". This is because the question is asking for the terms used to describe the first line in a request message and the first line in a response message in HTTP. However, "None" is not a valid term for either of these lines. The request line and the status line are the correct terms for the first lines in a request message and a response message, respectively.

A router is a networking device that is responsible for directing data packets from one network to another. It examines the destination IP address of each packet and determines the best path for it to reach its destination. The router then forwards the packet to the appropriate output link, ensuring that it reaches the intended recipient. Therefore, the statement that the primary role of a router is to forward datagrams from input links to output links is true.

An operating system identifies the application to which data coming in from the network should be relayed by the port number carried by the transport protocol. Each application is assigned a unique port number, and when data is received, the operating system checks the port number to determine which application should receive the data. This allows for proper routing and delivery of network data to the correct application.

In a connectionless communication network, packets are sent independently and do not follow a specific route or sequence. Therefore, it is possible for the packets to arrive at the destination in any order. Additionally, since the packets can traverse different routes, there is also a possibility that they may have taken different paths before reaching the destination. Thus, the correct answer is that the packets can arrive in any order, after possibly having traversed different routes.

Transmission bandwidth refers to the amount of data that can be transmitted over a network in a given period of time. Since the advent of Ethernet technology, the transmission bandwidth has significantly increased. With advancements in technology, the capacity of Ethernet networks has improved, allowing for faster and more efficient data transmission. Therefore, the transmission bandwidth is the feature of Ethernet that has not remained constant over time.

IP (Internet Protocol) is the correct answer because it is the network-layer protocol of the Internet. IP is responsible for routing packets of data between different networks, allowing for communication and data transfer across the Internet. Ethernet is a data link layer protocol, Telnet is an application layer protocol, and HTTP is also an application layer protocol used for web communication.

In a broadcast-based network, longer propagation delays significantly decrease the benefit of sensing the carrier before transmitting. This is because longer propagation delays mean that it takes more time for a signal to reach its destination. If the carrier sensing mechanism waits for the signal to reach its destination before transmitting, it will result in a significant delay in transmitting data. Therefore, the benefit of sensing the carrier before transmitting is diminished in the presence of longer propagation delays.

The correct answer is "protocol stack" because the protocols of the various layers in a network are organized in a stack-like structure, where each layer interacts with the layers above and below it. This allows for a modular and hierarchical approach to network communication, where each layer performs specific functions and passes data to the next layer in the stack. The term "protocol stack" accurately describes this arrangement of protocols in a layered system.

The purpose of the SNMP SetRequest message is to allow a managing entity to set the values of one or more MIB objects in a managed device. This message enables the managing entity to remotely configure and control the managed device by modifying the values of the MIB objects. It provides a means for the managing entity to make changes and updates to the configuration and behavior of the managed device through SNMP.

FTP client and web browser typically transmit packets over TCP. FTP (File Transfer Protocol) is a standard network protocol used to transfer files from one host to another over a TCP-based network, making it reliable and ensuring that all packets are delivered in the correct order. Similarly, web browsers use TCP to establish a connection with web servers and transmit HTTP requests and receive HTTP responses, ensuring the reliable delivery of data packets. Audio streaming, on the other hand, can use either TCP or UDP (User Datagram Protocol) depending on the specific application or streaming service.

The given formula calculates the time needed to transmit an L-bit packet into a link. It is obtained by dividing the size of the packet (L bits) by the transmission rate (R bits/sec). This formula is used to determine the delay in transmitting a packet from the source to the destination. Therefore, the correct answer is "packet transmission delay."

The statement is false. In a non-persistent HTTP connection, only one object can be sent over a single TCP connection between the client and server. After the object is sent, the connection is closed, and a new connection needs to be established for sending another object. This is different from a persistent connection, where multiple objects can be sent over the same TCP connection without closing it.

HTTP (Hypertext Transfer Protocol) is the correct answer because it is the protocol used for communication between a web server and a web browser. It allows for the transfer of hypertext, which includes text, images, links, and other multimedia content, over the Internet. HTTP is the foundation of data communication for the World Wide Web and enables the retrieval and display of web pages. FTP (File Transfer Protocol) is used for transferring files, Telnet is used for remote access to computers, and the World Wide Web (WWW) is the collection of web pages and websites accessible through the Internet.

ADSL (Asymmetric Digital Subscriber Line) is a type of internet connection that provides unequal bandwidth for downloading and uploading data. In ADSL, the downstream bandwidth, which refers to the speed at which data is received from the internet, is higher than the upstream bandwidth, which is the speed at which data is sent to the internet. This is because most internet users tend to consume more data by downloading files, streaming videos, etc., rather than uploading large amounts of data. Therefore, the statement that each subscriber gets more downstream bandwidth than upstream bandwidth in ADSL is true.

The IP address space is organized in a hierarchy to make the routing task more scalable. This means that the IP addresses are grouped and organized in a way that allows for efficient routing of data packets across the internet. Additionally, the hierarchy allows institutions managing local-area networks to have autonomous control over the assignment of addresses to computers within their network. This gives them the flexibility and control to manage their network's addressing needs. Therefore, the correct answer is I and III only.

Connection-based protocols require establishing a connection between the sender and receiver before data transmission can occur. This process incurs high startup costs, as it involves additional overhead and resources to establish and maintain the connection. These costs can include time, processing power, and network bandwidth. Therefore, high startup costs are a disadvantage of connection-based protocols.

Link-layer packets are called frames. In computer networking, a frame is a unit of data that is transmitted over a physical link or network. It contains the source and destination addresses, error checking information, and the actual data being transmitted. Frames are used in the link layer of the OSI model to encapsulate and transmit data between network devices.

The segment refers to a unit of data that is generated at the transport layer of the OSI model. This layer is responsible for ensuring reliable communication between the source and destination systems. The transport-layer packet contains the segment along with additional information such as source and destination port numbers. This packet is then encapsulated into a network-layer packet for further transmission across the network.

Measurement A calculates the throughput based on the total amount of data received by the browser, while Measurement B calculates the throughput based on the total amount of data received by the operating system on behalf of the browser. Since the operating system may receive additional data on behalf of the browser, Measurement B will generally be larger than Measurement A. Therefore, the statement "A is smaller than B" is true.

Layers four and five of the Internet protocol stack, namely the transport layer and the session layer, are responsible for functions such as establishing and terminating connections, managing data flow, and providing error detection and correction. These layers are implemented in the end systems, such as computers and mobile devices, as they directly interact with the applications and users. On the other hand, routers in the network core are responsible for forwarding packets based on the information in the network layer (layer three) and do not need to implement layers four and five. Therefore, the statement that layers four and five are implemented in the end systems but not in the routers in the network core is true.

The correct answer is "Value is the hostname of the mail server that has the alias hostname Name." This is because MX (Mail Exchanger) records are used to specify the mail server responsible for accepting email messages on behalf of a domain. The value in the MX record is the hostname of the mail server that should handle incoming mail for the specified domain.

Upgrading to a small 10 Base-T switch to connect the existing hub would be the best suggestion. This is because the current network performance is lacking and the computers in the laboratory place a modest and constant load on the network. By using a switch, the network can handle the load more efficiently and effectively, resulting in improved network performance. Replacing the hubs with 100 Base-T hub or 10 Base-T switches might be excessive for the modest load, and a new bank of dial-up modems would not be suitable for improving network performance in this scenario.

Web documents do not require real-time transmission, as they are not time-sensitive. They also do not require elastic throughput, as the amount of data transferred is typically small. Additionally, web documents do not involve real-time audio/video or interactive gaming, so there is no risk of data loss. Therefore, the transport service requirements of no data loss, elastic throughput, and not being time-sensitive are demanded for web documents.

The Physical layer of the OSI model is responsible for converting digital data into electrical signals and transmitting them over the physical medium, such as cables. It takes the ones and zeroes of the data and encodes them into a format that can be transmitted as electrical signals. Therefore, the Physical layer is the correct answer for this question.

IEEE standard Ethernet CSMA/CD provides error detection services to the network layer. This means that it is capable of detecting errors that may occur during data transmission. However, it does not provide error correction or reliable data transfer services. Error detection is important as it allows the network layer to identify and handle any errors that may have occurred during the transmission process, ensuring the integrity of the data being transmitted.

When the application running on host cs.cmu.edu wants to send a packet to host ee.cmu.edu, the first event that will happen is a DNS lookup. This is because the application needs to resolve the domain name (ee.cmu.edu) to an IP address before it can send the packet. The DNS lookup will query the DNS server to obtain the IP address associated with the domain name, allowing the application to establish a connection and send the packet.

Store and Forward is the correct answer because it refers to a packet-switching technique where the packet switch receives the entire packet before transmitting any part of it. This means that the switch stores the entire packet in its memory and checks for errors before forwarding it to the outbound link. This technique ensures reliable data transmission as it allows for error checking and correction before forwarding the packet. It also introduces queuing delays as the switch needs to wait for the entire packet to be received before transmitting it.

A forwarding table is used to find the proper interface to which the input interface should forward a packet. It helps the router determine the next hop for a packet based on its destination IP address. The forwarding table is usually populated through routing protocol messages received by the router, which allows it to learn about the network topology and make informed forwarding decisions. The table is not configured using a centralized routing algorithm, as mentioned in option B, but rather it is dynamically updated based on the routing information received from neighboring routers.

The correct answer is the requested object itself (represented by data data data data data). This is because the entity body in an HTTP response message contains the actual content or data that was requested by the client. In this case, the entity body is represented by the text "data data data data data". The other sections of the response message, such as the status line and header lines, provide additional information about the response and the server, but the entity body is where the requested object is found.

Transmission delay refers to the amount of time it takes to push all of the packet's bits into the link. It includes the time required to transmit the packet from the sender to the receiver over the physical medium. The transmission delay is influenced by factors such as the bandwidth of the link and the size of the packet.

In the network layer, data is divided into smaller units called datagrams. These datagrams contain the necessary information to route the data across different networks. Unlike frames or segments, which are specific to the data link and transport layers respectively, datagrams are specifically used in the network layer for efficient routing and delivery of data packets.