Chapter 10: Data Communication and Internet Services (Set-1)
In a basic data communication system, which component creates and sends the data toward the destination
A Receiver device
B Medium channel
C Protocol rules
D Sender device
The sender is the source that generates the message (data) and transmits it using a communication medium, following agreed rules so the receiver can understand it correctly.
Which component in data communication actually carries signals between devices
A Transmission medium
B Message content
C Receiver system
D Data protocol
The transmission medium is the path used for carrying signals, such as copper cable, fiber optic, or wireless radio waves, between the sender and receiver.
In data communication, what does the term “protocol” mainly mean
A Data size limit
B Network speed
C Communication rules
D Cable type
A protocol is a set of rules that defines how data is formatted, sent, received, checked for errors, and acknowledged so different devices can communicate reliably.
Which mode allows data to travel in only one direction at a time, permanently
A Half-duplex mode
B Simplex mode
C Full-duplex mode
D Packet mode
Simplex communication is one-way only. The receiver cannot send back data on the same channel, like a TV broadcast where information flows only from station to viewer.
Which communication mode supports two-way data, but not at the same time
A Half-duplex mode
B Simplex mode
C Full-duplex mode
D Circuit mode
Half-duplex supports both directions, but only one side transmits at a time. Walkie-talkies use this mode where one person speaks while the other listens.
Which mode allows simultaneous sending and receiving between two devices
A Simplex mode
B Half-duplex mode
C Full-duplex mode
D Batch mode
Full-duplex communication allows both sides to transmit and receive at the same time, like modern phone calls where both people can speak and listen simultaneously.
Bandwidth in networking is best described as
A Channel capacity
B Message length
C IP address range
D Device memory
Bandwidth means the maximum data-carrying capacity of a communication channel. Higher bandwidth generally allows more data to be transmitted per second under good conditions.
Transmission speed is usually measured in
A Bytes per file
B Pixels per inch
C Bits per second
D Frames per second
Network transmission speed commonly uses bps (bits per second) like Kbps, Mbps, or Gbps, describing how fast data can be sent over a connection.
In communication signals, noise mainly causes
A Better encryption
B More bandwidth
C Faster routing
D Signal distortion
Noise is unwanted electrical or radio interference that can corrupt data signals, leading to errors, retransmissions, slower performance, or loss of clarity in communication.
Attenuation in a transmission medium refers to
A Signal weakening
B Data compression
C Address mapping
D Packet switching
Attenuation is the gradual loss of signal strength over distance. Repeaters or amplifiers may be used to restore signal power so data remains readable.
Modulation is mainly used to
A Delete packets
B Change signal form
C Store cookies
D Assign IPs
Modulation changes a carrier signal to carry data, like varying amplitude, frequency, or phase. It helps transmit data effectively over wireless links and many wired systems.
Which model has exactly seven layers
A OSI model
B TCP/IP model
C Peer model
D Client model
The OSI reference model divides network functions into seven layers, helping standardize how data moves from applications down to physical transmission and back up again.
In the OSI model, the layer responsible for routing packets is
A Session layer
B Physical layer
C Presentation layer
D Network layer
The Network layer handles logical addressing and routing so packets can travel across multiple networks, selecting paths and forwarding packets toward the destination.
In OSI, which layer deals with frames and MAC addressing
A Network layer
B Transport layer
C Data Link layer
D Application layer
The Data Link layer provides node-to-node delivery on the same network segment, uses frames, and typically relies on MAC addresses for local delivery.
In OSI, which layer handles end-to-end delivery and reliability
A Transport layer
B Physical layer
C Presentation layer
D Data Link layer
The Transport layer provides end-to-end communication services like segmentation and reliability. Protocols like TCP operate here, ensuring ordered delivery and retransmission if needed.
In OSI, which layer is closest to the transmission medium
A Network layer
B Session layer
C Physical layer
D Application layer
The Physical layer transmits raw bits over the medium using electrical, optical, or radio signals. It defines connectors, voltages, frequencies, and physical data rates.
The TCP/IP model is commonly described using
A Four layers
B Seven layers
C Five layers
D Two layers
TCP/IP is often explained as four layers: Link, Internet, Transport, and Application. It matches real internet protocols and how data is handled in modern networks.
Encapsulation in networking means
A Removing headers
B Adding headers
C Deleting DNS
D Blocking ports
Encapsulation is the process of wrapping data with protocol information (headers, sometimes trailers) at each layer so it can be correctly delivered, routed, and interpreted.
Which protocol provides reliable, connection-oriented delivery
A UDP
B IP
C DNS
D TCP
TCP establishes a connection and uses acknowledgments, sequencing, and retransmissions to provide reliable ordered delivery, which is important for web pages, email, and file transfers.
Which protocol is connectionless and faster but not reliable by default
A TCP
B FTP
C UDP
D SMTP
UDP sends data without establishing a connection, reducing overhead. It is used where speed matters, like streaming or voice, while applications may handle loss if needed.
IP mainly provides
A Logical addressing
B User authentication
C Email formatting
D File compression
IP is responsible for logical addressing and routing across networks. It helps move packets from a source IP to a destination IP through routers on the internet.
Which protocol is mainly used to load web pages in browsers
A FTP
B SMTP
C HTTP
D POP3
HTTP is the web communication protocol used by browsers and web servers. It works with requests and responses to fetch pages, images, and other resources.
Which protocol is used for sending emails from a client to a mail server
A DNS
B SMTP
C DHCP
D IMAP
SMTP (Simple Mail Transfer Protocol) is used to send outgoing mail to a mail server and between mail servers. Receiving is usually handled by POP3 or IMAP.
DNS is mainly used to
A Map names to IPs
B Encrypt webpages
C Store cookies
D Boost bandwidth
DNS translates a human-friendly domain name (like a website name) into an IP address so computers can locate the correct server on a network.
A domain name is best described as
A Device serial number
B MAC identifier
C Router password
D Human-readable address
A domain name is an easy-to-remember text name used on the internet. DNS resolves it into an IP address so the correct server can be reached.
DNS caching mainly helps by
A Slowing browsing
B Blocking trackers
C Reducing lookups
D Increasing noise
Caching stores recently resolved DNS results, so repeated visits can reuse stored mappings. This reduces query time and load on DNS servers, improving browsing speed.
A DNS resolver is typically a
A Client-side query service
B Fiber cable type
C Physical router port
D Email storage
A DNS resolver is the component that asks DNS servers for name-to-IP mappings. It may be in your OS, router, or ISP, and often supports caching.
DHCP is mainly used to
A Create web pages
B Assign IP addresses
C Encrypt FTP
D Send emails
DHCP automatically assigns network settings like IP address, subnet mask, gateway, and DNS servers to devices, reducing manual configuration errors.
A DHCP lease refers to
A Permanent IP
B MAC address
C Temporary assignment
D VPN tunnel
A DHCP lease is a time-limited allocation of an IP address to a device. The device must renew the lease or get a new one when it expires.
A static IP address is
A Manually fixed
B Always changing
C Randomly generated
D Cache-only address
A static IP is typically set manually or reserved, and it stays the same. It is useful for servers, printers, or services that need a consistent reachable address.
The default gateway is usually the
A DNS server address
B MAC address value
C File server name
D Local router address
The default gateway is the router IP that forwards traffic to other networks. If the destination is outside the local network, devices send packets to the gateway.
A subnet mask is used to
A Identify network part
B Hide passwords
C Compress packets
D Assign MACs
The subnet mask helps determine which portion of an IP address is the network and which is the host. This controls local delivery and routing decisions.
HTTPS is different from HTTP because it
A Removes headers
B Blocks DNS
C Adds encryption
D Changes IP format
HTTPS uses SSL/TLS to encrypt data between browser and server, helping protect logins and sensitive information from eavesdropping and tampering during transmission.
The browser padlock generally indicates
A Higher bandwidth
B Faster DNS
C Smaller cookies
D Encrypted connection
A padlock usually means the site is using HTTPS with a valid certificate and traffic is encrypted, making it harder for attackers to intercept or modify data in transit.
SSL/TLS is mainly used to
A Route packets
B Secure communication
C Assign IP leases
D Format emails
SSL/TLS provides encryption, integrity, and server identity verification for network connections. It is widely used with HTTPS and other secure services.
A URL typically contains
A Protocol and host
B Only MAC address
C Only subnet mask
D Only port number
A URL commonly includes a scheme (like http/https), a host (domain), and often a path. It may also include a port, query string, and fragments.
In HTTP, a GET request is mainly used to
A Upload a file
B Assign an IP
C Fetch a resource
D Encrypt data
GET is used to request data from a server, like a webpage. It typically does not change server data, and parameters may appear in the URL query string.
In HTTP, a POST request is commonly used to
A Send form data
B Resolve DNS
C Set subnet mask
D Run traceroute
POST sends data in the request body, often used for form submission or uploading content. It can change server-side data and is not limited by URL length.
HTTP status code 404 generally means
A Server accepted request
B Redirect success
C Access granted
D Resource not found
A 404 response indicates the server could not find the requested page or resource at the given URL. The server is reachable, but the content is missing.
HTTP status code 301 indicates
A Permanent redirect
B Temporary error
C Unauthorized access
D Bad request
301 means the resource has permanently moved to a new URL. Browsers and search engines may update stored links to the new address automatically.
Cookies in web browsing are mainly used to
A Increase bandwidth
B Replace DNS
C Store small data
D Hide IP address
Cookies store small pieces of data in the browser, such as session IDs or preferences. They help websites remember users, maintain logins, and personalize settings.
A web session is typically maintained using
A MAC address only
B Session ID cookie
C Subnet mask value
D DHCP lease time
Many sites use a session ID stored in a cookie to link your browser to server-side session data, enabling login persistence and tracking actions during a visit.
FTP is mainly used for
A File transfer
B Web page display
C Name resolution
D IP assignment
FTP transfers files between a client and server, supporting uploading and downloading. It often requires authentication and is used for website file management and backups.
The standard control port for FTP is
A 25
B 80
C 443
D 21
FTP commonly uses port 21 for the control connection where commands and responses are exchanged. Data transfer uses separate connections, depending on active or passive mode.
Port 80 is commonly used for
A HTTPS
B SMTP
C HTTP
D DNS
Port 80 is the default for HTTP web traffic. Secure web traffic typically uses port 443 for HTTPS, while email and DNS use different standard ports.
Port 443 is commonly used for
A HTTPS
B FTP
C POP3
D DHCP
Port 443 is the standard port for HTTPS, where SSL/TLS secures the connection. Browsers use it to load secure websites; it is widely used for logins and payments.
SFTP is best understood as
A FTP without login
B Web browsing tool
C DNS caching method
D Secure file transfer
SFTP provides secure file transfer over an encrypted connection (commonly over SSH). It protects data and credentials, unlike basic FTP which may transmit them insecurely.
The command “ping” is mainly used to
A Send an email
B Assign IP addresses
C Test connectivity
D Encrypt traffic
Ping checks whether a host is reachable and measures round-trip time using ICMP messages. It helps diagnose network connectivity issues between your device and a server.
Traceroute is mainly used to
A Find routing path
B Set DNS records
C Download files
D Increase bandwidth
Traceroute shows the path packets take across routers to a destination. It helps identify where delays or failures occur by listing each hop and its response times.
NAT in home networks mainly helps by
A Assigning MAC addresses
B Sharing one public IP
C Creating DNS zones
D Blocking all traffic
NAT lets many private devices share a single public IP address by translating internal addresses to the router’s public address. It conserves IPv4 addresses and adds basic isolation.