Network_Questions
What four functions do all routers perform?
1. Connect dissimilar networks. 2. Interpret Layers 3 and 4 addressing and other information. 3. Determine the best path for data to follow. 4. Reroute traffic if a primary path is down but another path is available.
57. Which OSI layer is responsible for directing data from one LAN to another? A. Transport layer B. Network layer C. Data Link layer D. Physical layer
B) Network Layer Explanation: Network Layer (Layer 3). This layer manages the routing of data packets across multiple networks and is where routing protocols operate. Routers, which work at the Network Layer, are devices that forward data packets between different LANs or segments of a network, based on their IP addresses. This is crucial for the functionality of the internet and large enterprise networks, where data must be efficiently directed across various paths to reach its destination.
What field in a TCP segment is used to determine if an arriving data unit exactly matches the data unit sent by the source? A. Source port B. Acknowledgment number C. Data D. Checksum
D) Checksum Explanation: the Checksum field is used to determine if an arriving data unit exactly matches the data unit sent by the source. The TCP checksum is a form of redundancy check that is used for error-detection. It is calculated by the sender over the entire TCP segment, including both header and data sections. When the segment arrives at the receiver, the receiver calculates the checksum of the segment again. If the calculated checksum matches the one found in the checksum field of the received TCP segment, the receiver can be confident that the segment arrived intact and without errors.
What is the purpose of Domain Name System?
Domain Name System can map a name to an address and conversely an an address to name.
Discuss the TCP connections needed in FTP
FTP establishes two connections between the hosts. One connection is used for data transfer, the other for control information. The control connection uses very simple rules of communication. The data connection needs more complex rules due to the variety of data types transferred.
Discuss the three main division of the domain name space.
Generic domain: Define registered hosts according to their generic behavior, uses genericsuffixes. Country domain: Uses two characters to identify a country as the last suffix. Inverse domain: Finds the domain name given the IP address.
In what way is instant messaging a hybrid of client-server and P2P architecture?
Instant Messaging involves the initiator to contact a centralized server to locate the address (IP address.) of the receiver: client server model. After this, the instant messaging can be peer to peer - message between the two communicating parties are sent directly between them.
Suppose you are sending an email from your Hotmail account to your friend, who reads his/her e-mail from his/her mail server using IMAP. Briefly describe how your email travels from your host to your friend's host. Also, what are the application- layer protocols involved?
Message is sent from your host to your mail server over HTTP. Your mail server then sends the message to your friend's mail server over SMTP. Your friend then transfers the message from his/her mail server to his/her host over IMAP.
Name four factors needed for a secure network.
Privacy: The sender and the receiver expect confidentiality. Authentication: The receiver is sure of the sender's identity and that an imposter has not sent the message. Integrity: The data must arrive at the receiver exactly as it was sent. Non-Reputation: The receiver must able to prove that a received message came from a specific sender.
Why do you think DNS uses UDP, instead of TCP, for its query and response messages?
TCP involves a connection establishment phase while UDP does not. Using TCP for DNS may end up involving several TCP connections to be established since several name servers may have to be contacted to translate a name into an IP address. This imposes a high overhead in delay that is acceptable for larger transfers but not acceptable for very short messages such as DNS queries and responses. In addition, UDP affords a smaller packet size and also imposes a smaller load on name servers due to its simplicity in comparison to TCP.
What three characteristics distinguish TCP from UDP?
TCP is connection-oriented, uses sequencing and checksums, and provides flow control
What is the function of SMTP?
The TCP/IP protocol supports electronic mail on the Internet is called Simple Mail Transfer (SMTP). It is a system for sending messages to other computer users based on e-mail addresses. SMTP provides mail exchange between users on the same or different computers.
Discuss the basic model of FTP.
The client has three components: the user interface, the client control process, and the client data transfer process. The server has two components: the server control process and the server data transfer process. The control connection is made between the control processes. The data connection is made between the data transfer processes.
What process is used to establish a TCP connection?
Three-way handshake Explanation:
Why is SMTP not used for transferring e-mail messages from the recipient's mail server to the recipient's personal computer?
Whereas SMTP is a push protocol; the task of transferring e-mail messages from the recipient's mail server to the recipient's personal computer is a pull operation. It is only used for sending email messages and cannot make a server request like HTTP.
How many layers are there in the ISO OSI reference model? a) 7 b) 5 c) 4 d) 6
a) 7
Which of the following is false with respect to UDP? a) Connection-oriented b) Unreliable c) Transport layer protocol d) Low overhead
a) Connection-oriented Explanation: UDP is a standardized method for transferring data between two computers in a network. Compared to other protocols, UDP accomplishes this process in a simple fashion: it sends packets (units of data transmission) directly to a target computer, without establishing a connection first, indicating the order of said packets, or checking whether they arrived as intended. (UDP packets are referred to as 'datagrams'.)
Two broad categories of congestion control are a) Open-loop and Closed-loop b) Open-control and Closed-control c) Active control and Passive control d) Active loop and Passive loop
a) Open-loop and Closed-loop Explanation: Open loop congestion control techniques are used to prevent congestion before it even happens by enforcing certain policies. Closed loop congestion control techniques are used to treat congestion after it has happened.
Which of this is not a network edge device? a) Switch b) PC c) Smartphones d) Servers
a) Switch
Which is the correct expression for the length of UDP datagram? a) UDP length = IP length - IP header's length b) UDP length = UDP length - UDP header's length c) UDP length = IP length + IP header's length d) UDP length = UDP length + UDP header's length
a) UDP lenght = IP length - IP header's length Explanation: A user datagram is encapsulated in an IP datagram. There is a field in the IP header that defines the total length of the IP packet. There is another field in the IP header that defines the length of the header. So if we subtract the length of the IP header that is encapsulated in the IP packet, we get the length of UDP datagram.
43. Application layer data lives in the _____ section of the transport layer protocol. a) data payload b) header c) footer d) flags
a) data payload Explanation: The payload section of one layer contains the content of the layer above it.
Which one of the following is not a function of network layer? a) congestion control b) error control c) routing d) inter-networking
a) error control
How is a single channel shared by multiple signals in a computer network? a) multiplexing b) phase modulation c) analog modulation d) digital modulation
a) multiplexing
Which of the following computer networks is built on the top of another network? a) overlay network b) prime network c) prior network d) chief network
a) overlay network
1. The instantiation of an endpoint in a potential TCP connection is known as a ______. a) socket b) port c) sequence number d) TCP segment
a) socket Explanation: A socket connects the networking stack of an operating system to applications.
Which of the following networks extends a private network across public networks? a) virtual private network b) local area network c) storage area network d) enterprise private network
a) virtual private network Explanation: A virtual private network extends a private network across a public network, and enables users to send and receive data across shared or public networks as if their computing devices were directly connected to the private network.VPN provides enhanced security and online anonymity to users on the internet. It is also used to unblock websites which are unavailable in certain regions.
What port does the File Transfer Protocol (FTP) typically listen on? a) 443 b) 21 c) 25 d) 80
b) 21 Explanation: for command and control: This is the primary port used for opening the connection between the FTP client and FTP server. Through this port, commands are sent from the client to the server (e.g., login credentials, commands to change directories, list directories, etc.).
If a link transmits 4000 frames per second, and each slot has 8 bits, what is the transmission rate of the circuit using Time Division Multiplexing (TDM)? a) 500kbps b) 32kbps c) 32bps d) 500bps
b) 32kbps Explanation: Transmission rate= frame rate * number of bits in a slot.Given: Frame rate = 4000/sec and number of bits in slot = 8Thus, Transmission rate = (4000 * 8) bps= 32000bps= 32kbps
What is a computer network? a) A device used to display information on a computer screen b) A collection of interconnected computers and devices that can communicate and share resources c) A type of software used to create documents and presentations d) The physical casing that protects a computer's internal components
b) A collection of interconnected computers and devices that can communicate and share resources
What is the term for the data communication system within a building or campus? a) MAN b) LAN c) PAN d) WAN
b) LAN Explanation: LAN is an abbreviation for Local Area Network. This network interconnects computers in a small area such as schools, offices, residence etc. It is the most versatile kind of data communication system where most of the computer network concepts can be visibly used.
The checksum doesn't compute for a packet sent at the Internet Protocol (IP) level. What will happen to the data? a) The data will be sent back to the sending node with an error. b) The data will be discarded. c) The data will be resent. d) It will be sent, but may be out of order.
b) The data will be discarded Explanation: At the IP or ethernet level, if a checksum doesn't compute, all of the data is just discarded. It's up to TCP to determine when to resend this data.
How do two devices become part of a network? a) PIDs of the processes running of different devices are same b) a process in one device is able to exchange information with a process in another device c) a process is active and another is inactive d) a process is running on both devices
b) a process in one device is able to exchange information with a process in another device
Which layer provides the services to user? a) physical layer b) presentation layer c) session layer d) application layer
b) application layer Explanation: In networking, a user mainly interacts with application layer to create and send information to other computer or network. Application layer provides the interface between applications and the network. It is the top-most layer in both the TCP/IP and the OSI model.
The ______ field is used to detect errors over the entire user datagram. a) udp header b) checksum c) source port d) destination port
b) checksum Explanation: Checksum field is used to detect errors over the entire user datagram. Though it is not as efficient as CRC which is used in TCP, it gets the job done for the UDP datagram as UDP doesn't have to ensure the delivery of the packet
Which connection is necessary for a computer to join the internet? a) internet society b) internet service provider c) different computer d) internet architecture board
b) internet service provider Explanation: The ISPs (Internet Service Providers) are the main agents through which every computer is connected to the internet. They are licensed to allot public IP addresses to its customers in order to connect them to the internet.
Which topology requires a multipoint connection? a) Ring b) Bus c) Star d) Mesh
b)Bus Explanation: Bus topology is a type of network topology in which all devices are connected to a single cable called a "bus." This cable serves as a shared communication medium, allowing all devices on the network to receive the same signal simultaneously. Bus topology is commonly used in small to medium-sized local area networks (LANs), where it can be used to connect devices such as computers, printers, and other peripherals. It can also be used in industrial control systems and other specialized applications.
What is internet? a) A network of interconnected local area networks b) A collection of unrelated computers c) Interconnection of wide area networks d) A single network
c) Interconnection of wide area networks
What is the main advantage of UDP? a) More overload b) Reliable c) Low overhead d) Fast
c) Low overhead Explanation: As UDP does not provide assurance of delivery of packet, reliability and other services, the overhead taken to provide these services is reduced in UDP's operation. Thus, UDP provides low overhead, and higher speed.
At which OSI layer does IP operate? A. Application layer B. Transport layer C. Network layer D. Data Link layer
c) Network layer Explanation: operates at the Network Layer of the OSI (Open Systems Interconnection) model, which is Layer 3. The Network Layer is responsible for packet forwarding including routing through intermediate routers, as it provides the functional and procedural means of transferring variable length data sequences (packets) from one node to another connected in different networks. IP is a core protocol that defines addressing and routing to enable data packets to be delivered across networks.
What number does a host use to identify the application involved in a transmission? A. IP address B. MAC address C. Port number D. Sequence number
c) Port number Explanation: Port numbers are part of the transport layer protocols like TCP (Transmission Control Protocol) and UDP (User Datagram Protocol). They serve as communication endpoints for each application or process running on a host. When data is sent from one computer to another over the internet or a local network, the port number tells the receiving computer which application should receive the message.
What type of transmission is involved in communication between a computer and a keyboard? a) Half-duplex b) Full-duplex c) Simplex d) Automatic
c) Simplex Explanation: In simplex transmission, data flows in single direction which in this case refers to the data flowing from the keyboard to the computer. Another example would be of the mouse where the data flows from the mouse to the computer only.
Which network topology requires a central controller or hub? a) Ring b) Bus c) Star d) Mesh
c) Star Explanation: In star topology, no computer is connected to another computer directly but all the computers are connected to a central hub. Every message sent from a source computer goes through the hub and the hub then forwards the message only to the intended destination computer.
42. HTTP is an example of a(n) ______ layer protocol. a) transport b) data-link c) application d) network
c) application Explanation: There are lots of application layer protocols, but HTTP is one of the most common ones.
1. Which of the following maintains the Domain Name System? a) a single server b) a single computer c) distributed database system d) none of the mentioned'
c) distributed database system Explanation: The Domain Name System (DNS) is a distributed database system that translates domain names to numerical Internet Protocol (IP) addresses. It is an essential part of Internet infrastructure.
Which layer does the data link layer take packets from and encapsulate them into frames for transmission? a) transport layer b) application layer c) network layer d) physical layer
c) network layer Explanation: The network layer is responsible for receiving frames from the data link layer, and delivering them to their intended destinations among based on the addresses contained inside the frame. The network layer finds the destination by using logical addresses, such as IP (internet protocol). At this layer, routers are a crucial component used to quite literally route information where it needs to go between networks.
What is the term for an endpoint of an inter-process communication flow across a computer network? a) port b) machine c) socket d) pipe
c) socket
Which layer is responsible for process to process delivery in a general network model? a) session layer b) data link layer c) transport layer d) network layer
c) transport layer Explanation: The role of Transport layer (Layer 4) is to establish a logical end to end connection between two systems in a network. The protocols used in Transport layer is TCP and UDP. The transport layer is responsible for segmentation of the data. It uses ports for the implementation of process-to-process delivery.
Which of the following are Gigabit Ethernets? a) 1000 BASE-LX b) 1000 BASE-CX c) 1000 BASE-SX d) All of the mentioned
d) All of the mentioned
When discussing IDS/IPS, what is a signature? a) It refers to "normal," baseline network behavior b) It is used to authorize the users on a network c) An electronic signature used to authenticate the identity of a user on the network d) Attack-definition file
d) Attack-definition file Explanation: Signature-based detection compares signatures against observed events to identify possible incidents. This is the simplest detection method because it compares only the current unit of activity (such as a packet or a log entry to a list of signatures) using string comparison operations.
Beyond IP, UDP provides additional services such as _______ a) Routing and switching b) Sending and receiving of packets c) Multiplexing and demultiplexing d) Demultiplexing and error checking
d) Demultiplexing and error checking Explanation: De-multiplexing is the delivering of received segments to the correct application layer processes at the recipients end using UDP. Error checking is done through checksum in UDP.
Retransmission of packets must not be done when _______ a) Packet is lost b) Packet is corrupted c) Packet is needed d) Packet is error-free
d) Packet is error-free Explanation: not retransmitting error-free packets is a deliberate strategy to make the best use of network resources, reduce communication delays, and ensure reliable data transfer without unnecessarily burdening the network.
The transport layer handles multiplexing and demultiplexing through what type of device? a) Hubs b) Switches c) Routers d) Ports
d) Ports Explanation: The transport layer handles multiplexing and demultiplexing through ports.
Which of the following allows you to connect and login to a remote computer? a) SMTP b) HTTP c) FTP d) Telnet
d) Telnet Explanation: It is a type of protocol that enables one computer to connect to the local computer. It is used as a standard TCP/IP protocol for virtual terminal service which is provided by ISO. The computer which starts the connection is known as the local computer.
In which scenario should you use the User Datagram Protocol (UDP)? a) When you are using instant messaging with a co-worker b) When you are sending an email c) When you are streaming a video d) When you make a phone call
d) When you make a phone call
What are nodes in a computer network? a) the computer that routes the data b) the computer that terminates the data c) the computer that originates the data d) all of the mentioned
d) all of the mentioned
Which of the following is used in an attempt to render a computer resource unavailable to its intended users? a) botnet process b) worms attack c) virus attack d) denial-of-service attack
d) denial-of-service attack Explanation: In a Denial of Service attack, the attacker won't let the victims access the network by using a certain method that ensures that an essential network resource is unavailable to the victim. The methods that the attacker can use are vulnerability attack, bandwidth flooding and connection flooding
When a collection of various computers appears as a single coherent system to its clients, what is this called? a) mail system b) networking system c) computer network d) distributed system
d) distributed system
Which of the following is the network layer protocol for the internet? a) hypertext transfer protocol b) file transfer protocol c) ethernet d) internet protocol
d) internet protocol Explanation: There are several protocols used in Network layer. Some of them are IP, ICMP, CLNP, ARP, IPX, HRSP etc. Hypertext transfer protocol is for application layer and ethernet protocol is for data link layer.
Which of the following is an example of Bluetooth? a) wide area network b) virtual private network c) local area network d) personal area network
d) personal area network
Which of the following devices forwards packets between networks by processing the routing information included in the packet?a) firewall b) bridge c) hub d) router
d) router
What database does a router consult before determining the most efficient path for delivering a message?
its routing table
