Chapter 10: Data Communication and Internet Services (Set-3)
A communication channel with higher bandwidth can generally carry
A More data per second
B More IP addresses
C More MAC entries
D More DNS records
Bandwidth is the channel’s capacity. Higher bandwidth usually allows more bits to be transmitted each second, so large files, video, and multiple users can be handled more smoothly.
When a signal is regenerated to overcome attenuation on long links, the device used is often a
A DNS resolver
B Proxy server
C Repeater device
D DHCP client
A repeater receives a weak or distorted signal and regenerates it to restore strength and shape. This helps data travel longer distances without errors caused by attenuation.
Which statement correctly describes full-duplex communication on a network link
A One-way only
B Alternate directions only
C Only broadcast traffic
D Both transmit simultaneously
Full-duplex allows sending and receiving at the same time. This improves performance because both ends can communicate without waiting, unlike half-duplex which alternates directions.
In half-duplex communication, two devices can
A Talk one at time
B Talk both same time
C Only receive data
D Only send data
Half-duplex supports two-way communication but not simultaneously. Devices must take turns transmitting, which can reduce efficiency compared to full-duplex in busy communication.
In data communication, which factor most directly reduces signal quality by adding random disturbances
A Static IP use
B DNS caching
C Noise presence
D Port numbering
Noise is unwanted interference that changes the signal’s shape. It increases bit errors, causes retransmissions, and reduces effective data rate, especially on long or poorly shielded links.
Modulation is commonly required in wireless communication because it
A Carries data on carrier
B Removes all noise
C Changes MAC addresses
D Assigns IP leases
Modulation places digital information onto a carrier wave by varying amplitude, frequency, or phase. This makes efficient radio transmission possible and supports different data rates and ranges.
In the OSI model, error detection at the frame level is mainly handled by
A Session layer
B Application layer
C Data Link layer
D Presentation layer
The Data Link layer provides reliable delivery over a single link using frames. It often uses error detection methods like CRC and controls access to the physical medium.
Which OSI layer is responsible for breaking large data into smaller segments and reassembling them
A Network layer
B Transport layer
C Physical layer
D Data Link layer
The Transport layer segments data for transmission and reassembles it at the destination. With TCP, it also ensures reliability using acknowledgments, sequencing, and retransmissions.
Which OSI layer is most associated with IP addressing and routing decisions
A Physical layer
B Session layer
C Presentation layer
D Network layer
The Network layer uses logical addressing and routing. It selects paths across networks and forwards packets through routers so data reaches the correct destination network.
In the TCP/IP model, TCP and UDP belong to the
A Internet layer
B Link layer
C Transport layer
D Physical layer
TCP and UDP operate at the Transport layer in TCP/IP. They provide process-to-process communication using port numbers and define how data is delivered between applications.
Which protocol is best suited when an application needs fast delivery and can tolerate some loss
A UDP protocol
B TCP protocol
C DNS protocol
D SMTP protocol
UDP has low overhead because it doesn’t establish a connection or guarantee delivery. It is widely used for streaming, voice, and quick queries where speed is important.
A key feature of TCP that improves reliability is
A No headers used
B No port numbers
C No segmentation
D Retransmission and ACK
TCP confirms received data using acknowledgments (ACKs). If data is missing, TCP retransmits it. This ensures accurate, ordered delivery, which is important for downloads and web pages.
IP is considered “connectionless” because it
A Encrypts every message
B Needs login credentials
C Forwards each packet independently
D Uses only one port
IP sends packets without establishing a dedicated connection. Each packet can take different routes, and delivery is not guaranteed by IP itself; reliability is usually provided by higher layers.
DNS uses caching mainly to reduce
A IP address length
B Repeated lookup delays
C Packet header size
D Router power usage
Caching stores recently resolved domain results. This reduces repeated queries to DNS servers and speeds up access to frequently visited sites, improving performance and lowering DNS traffic.
Which statement correctly describes a DNS resolver in a typical network
A It assigns IP leases
B It encrypts FTP traffic
C It queries DNS servers
D It forwards NAT tables
A DNS resolver performs name lookups by asking DNS servers and returning the final IP address to the client. It may also cache results to speed up future requests.
A DHCP server can provide all of the following to a client except
A MAC address label
B Subnet mask value
C Default gateway
D DNS server address
DHCP assigns network configuration like IP address, subnet mask, gateway, and DNS. A MAC address is a hardware identifier already assigned to the network interface, not given by DHCP.
In DHCP, what is the main purpose of the “lease time” value
A Encrypt IP traffic
B Store DNS records
C Increase link bandwidth
D Limit IP usage duration
Lease time controls how long a client can use an assigned IP before renewal is needed. This helps reuse addresses efficiently and prevents long-term conflicts in dynamic networks.
A device using a dynamic IP address can receive a different IP because
A DNS uses caching
B TCP uses ACK
C Lease can expire
D HTTP uses cookies
Dynamic IP addresses come from DHCP pools. When the lease expires or the device reconnects, the DHCP server may assign a different available address depending on network conditions.
A static IP is preferred for servers mainly because it
A Stays predictable
B Blocks all attacks
C Makes DNS useless
D Removes encryption need
Servers often need stable addressing so users, DNS records, and services can reliably reach them. A static IP avoids frequent changes that could break access or configuration.
Which term best describes the device that forwards traffic from a local LAN to the internet
A DNS cache
B FTP server
C Default gateway
D Session cookie
The default gateway is usually the router. When a destination is outside the local subnet, devices send packets to the gateway, which forwards them toward external networks.
In an HTTPS connection, encryption is provided mainly by
A DHCP protocol
B DNS protocol
C FTP protocol
D TLS protocol
HTTPS uses TLS to encrypt data between browser and server. TLS also provides integrity checks and supports server identity verification using certificates, improving safety during logins and payments.
Which item is used by browsers to verify a website’s identity in HTTPS
A Subnet mask
B DHCP lease
C Digital certificate
D MAC address
A certificate binds a domain name to a public key and is issued by a trusted authority. The browser verifies it to reduce impersonation and then uses it to set up encryption.
HTTP uses which basic pattern for communication between browser and server
A Request and response
B Broadcast and reply
C Lease and renew
D Ping and trace
HTTP works by clients sending requests for resources and servers replying with status codes and data. This simple model supports web pages, APIs, and many modern internet services.
Which HTTP method is generally used to submit form data to a server
A GET method
B TRACE method
C POST method
D HEAD method
POST sends data in the request body, making it suitable for form submissions and updates. It can carry larger data than GET and is used when the request changes server-side data.
Which HTTP method is mainly used to fetch a page or resource without changing server data
A POST method
B GET method
C PUT method
D CONNECT method
GET requests retrieve data such as pages or images. Parameters can appear in the URL, and servers typically treat GET as a read-only request, though caching can apply.
A web cookie is stored primarily on the
A DNS server
B DHCP server
C Router firmware
D User’s browser
Cookies are small pieces of data saved in the browser and sent back to the site on future requests. They often store session IDs or preferences to remember user state.
A session on a website is often tracked by
A MAC address only
B Subnet mask value
C Session ID cookie
D FTP port number
Many sites store session data on the server and use a session ID in a cookie to identify the user. This helps maintain login status and user actions across page requests.
In HTTP, caching is mainly useful to
A Speed repeated loading
B Increase signal noise
C Change IP mapping
D Shorten MAC address
Caching stores previously fetched content, like images or pages. Reusing cached copies reduces server requests, saves bandwidth, and improves browsing speed, especially on slower connections.
The standard port used for FTP control connection is
A Port 22
B Port 80
C Port 21
D Port 443
FTP uses port 21 for control commands like login and directory operations. Data transfer may use separate ports depending on active or passive FTP modes.
Which statement correctly distinguishes SFTP from FTP
A SFTP uses port 80
B SFTP is encrypted
C FTP is always secure
D FTP needs certificates
SFTP transfers files through an encrypted channel, commonly over SSH, protecting credentials and data. Traditional FTP may send credentials in plain text unless additional security is used.
In FTP, “passive mode” is often used to
A Remove user login
B Change IP address
C Work with firewalls
D Block all ports
Passive FTP helps clients behind NAT/firewalls by letting the client initiate data connections. This reduces incoming connection issues compared to active mode, improving compatibility.
In FTP, “active mode” generally means the server
A Connects back to client
B Uses only port 443
C Disables data transfer
D Encrypts with TLS only
In active mode, the client tells the server a port to connect back for data transfer. Firewalls may block this incoming server connection, which is why passive mode is common.
Which protocol is best matched with receiving email while keeping messages on the server for sync
A POP3 protocol
B SMTP protocol
C IMAP protocol
D FTP protocol
IMAP synchronizes email across devices by keeping messages on the server. It supports folders and flags, allowing users to read and manage the same mailbox from multiple devices.
POP3 is generally best described as
A Sync email folders
B Send outgoing mail
C Resolve website names
D Download email locally
POP3 mainly downloads messages from the mail server to the client. It is simpler than IMAP and may remove mail from the server depending on client settings.
SMTP is used primarily when you
A Send outgoing email
B Download mail inbox
C Map domain to IP
D Assign dynamic IP
SMTP handles sending mail from a client to a server and between mail servers. It is the standard protocol for email delivery, while reading is usually done through POP3 or IMAP.
A proxy server in an office network can help by
A Assigning MAC addresses
B Increasing attenuation
C Filtering user access
D Changing cable type
Proxies can enforce policies, block unwanted sites, log activity, and sometimes cache content to speed browsing. They sit between clients and the internet as an intermediary.
A VPN improves privacy mainly by
A Increasing DNS TTL
B Encrypting data tunnel
C Removing packet headers
D Disabling NAT tables
A VPN creates an encrypted tunnel between your device and a VPN server. This protects traffic on public Wi-Fi and can allow secure access to private resources over the internet.
NAT is important in many IPv4 networks mainly because it
A Replaces DNS servers
B Disables routing tables
C Saves public IPv4
D Increases cable length
NAT allows multiple private devices to share one public IPv4 address. The router translates internal addresses to the public one, reducing the number of public IPv4 addresses required.
A MAC address is used mainly for communication within
A Global internet routing
B DNS root servers
C HTTP web sessions
D Local network segment
MAC addresses work at the Data Link layer for local delivery on the same LAN. Routers use IP addresses to move data across networks, while MAC addresses change per local hop.
The “ping” command is based on
A SMTP commands
B TCP handshakes
C ICMP messages
D DNS records
Ping uses ICMP echo request and reply messages to test reachability and measure delay. It is a basic troubleshooting tool to check whether a host responds over the network.
Traceroute helps identify
A DNS record types
B Path of routers
C DHCP lease time
D HTTPS certificate chain
Traceroute reveals the sequence of network hops to a destination. It helps find where packets slow down or fail, which is useful for diagnosing routing or ISP issues.
Which term best describes a company that provides internet connectivity to users
A DNS resolver
B FTP client
C ISP provider
D Proxy cache
An ISP provides access to the internet through technologies like fiber, mobile data, or cable. ISPs often also provide DNS servers, modems/routers, and sometimes email or hosting services.
Web hosting typically includes
A Server space and access
B Only DNS caching
C Only IP leasing
D Only port scanning
Hosting services store website files on servers connected to the internet. They provide resources like storage, bandwidth, uptime, and web server software so users can access the site reliably.
VoIP calls are transmitted mainly as
A Analog cable signals
B DNS cached records
C Digital data packets
D DHCP lease files
VoIP converts voice into digital packets and sends them over IP networks. It needs low delay and stable connectivity; packet loss or jitter can reduce call quality.
Which feature is most directly related to “encapsulation” of data on a network
A Removing IP address
B Blocking HTTP cookies
C Reducing bandwidth usage
D Adding layer headers
Encapsulation wraps data with headers at each layer, such as TCP/UDP headers and IP headers. These headers help with addressing, routing, reliability, and correct interpretation at the receiver.
In networking, “protocol suite” is best understood as
A One physical cable
B Group of protocols
C A router function
D A browser feature
A protocol suite is a set of protocols designed to work together, such as the TCP/IP suite. It includes transport, internet, and application protocols used for modern networking.
A common real-life example of simplex communication is
A Phone conversation
B Walkie-talkie talk
C TV broadcast signal
D Video call chat
Simplex is one-way communication only. TV broadcasting sends signals from the station to viewers; viewers cannot transmit back on the same channel in that communication direction.
A common real-life example of half-duplex communication is
A Walkie-talkie talk
B Web browsing session
C Email sending
D Fiber optic link
Walkie-talkies operate half-duplex: both ends can speak, but only one at a time. The “push-to-talk” style shows how transmission alternates rather than happening simultaneously.
A common real-life example of full-duplex communication is
A TV broadcast
B One-way radio
C Telephone call
D Simple sensor output
Telephone calls are full-duplex because both parties can speak and listen at the same time. Modern networks support this by using separate channels or echo-cancellation techniques.
Transmission speed and bandwidth are related because
A Bandwidth means IP address
B Speed means DNS record
C Both mean MAC address
D Higher bandwidth supports higher speed
Bandwidth is the channel capacity, while speed is the rate data is transmitted. A higher bandwidth link can support higher speeds, though real speed also depends on noise and congestion.