Computer Knowledge

Computer Networks

2,461 Questions

Computer networks involve the architecture, protocols, and security measures used for digital communication. This collection covers OSI model layers, IP addressing, data transmission, and cryptographic standards. These concepts are vital for the computer knowledge sections of banking and government exams.

OSI model layersNetwork protocolsIP subnet maskingData encryption standardsServer configurationsNetwork commands

Computer Networks Questions

Multiple choice

Which three layers of the OSI Model make up the upper layers?

  1. Application, Presentation, Session

  2. Presentation, Session, Transport,

  3. Session, Transport, Network

  4. Transport, Network, Data Link
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The OSI model is divided into upper layers (Application, Presentation, Session) which deal with user-facing data, and lower layers (Transport, Network, Data Link, Physical) which deal with data transmission.

Multiple choice

Which description about IPv6 is not correct?

  1. IPv6 supports a hop limit of 255

  2. IPv6 interfaces must have a link-local address

  3. IPv6 natively incorporates IPSec

  4. IPv6 supports broadcasting
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

IPv6 does not support broadcasting; instead, it uses multicasting and anycasting to send data to specific groups or the nearest interface.

Multiple choice

Select the incorrect statement about higher level OSI layers

  1. Session - maintains the state of the ongoing connection

  2. Presentation - Encryption & Translation can occur at layer 6

  3. Application - resource sharing, remote file access and other

  4. Transport - transmission of packets
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The Transport layer is considered a lower layer, not a higher layer. The higher layers are Session, Presentation, and Application.

Multiple choice

What statement about IPv6 packet fragmentation is true?

  1. IPv6 fragmentation occurs at the routers

  2. IPv6 packet size is pre-determined on the sending host

  3. IPv6 MTU is hard set to 1500

  4. IPv6 fragmentation occurs at switches
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

In IPv6, routers do not perform fragmentation. Fragmentation is the responsibility of the source host, which determines the MTU and fragments the packet accordingly.

Multiple choice

Which layer - PDU match is incorrect?

  1. Network - Datagram

  2. Physical - bits

  3. Data Link - Frame

  4. Transport - Segment
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The PDU for the Network layer is a Packet, not a Datagram (though sometimes used interchangeably, Packet is the standard OSI term). However, in many contexts, Datagram is associated with Transport (UDP). Actually, the Network layer PDU is a Packet, so the match 'Network - Datagram' is technically incorrect in strict OSI terminology.

Multiple choice

Two common layer three protocols are:

  1. Ethernet and TCP

  2. ICMP and IPv6

  3. UDP and TCP

  4. IPv4 and STP
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

ICMP and IPv6 are both protocols that operate at the Network layer (Layer 3).

Multiple choice

What statements are true about VLAN tagging (best answer)?

  1. Located after the destination MAC and Tag is always 0x0800

  2. It is located after the Ether Type

  3. Located after the source MAC and Tag is always 0x8100

  4. Located after the destination MAC and Tag is always 0x8100
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The 802.1Q VLAN tag is inserted after the source MAC address, and the Tag Protocol Identifier (TPID) is 0x8100.

Multiple choice

Which is true for Next Header field in an IPv6 header.

  1. 1 byte field that uses same protocol numbers as IPv4

  2. 1 byte field that uses different protocol numbers than IPv4

  3. 2 byte field that uses same protocol numbers as IPv4

  4. 2 byte field that uses different protocol numbers than IPv4
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The Next Header field in IPv6 is 1 byte and uses the same protocol numbers as the Protocol field in IPv4.

Multiple choice

Which OSI layer and PDU are not correctly matched?

  1. Data Link - Frames

  2. Network - Packets

  3. Transport - Segments/Datagrams

  4. Session - Bits
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The OSI model defines PDUs for different layers: bits for Physical, frames for Data Link, packets for Network, and segments for Transport. The Session layer does not use bits as its PDU; bits are the PDU for the Physical layer.

Multiple choice

Which protocol would NOT use UDP?

  1. TFTP

  2. DNS

  3. DHCP

  4. SSH
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

SSH (Secure Shell) requires a reliable, connection-oriented transport to ensure data integrity and order, which is provided by TCP. TFTP, DNS, and DHCP are typically connectionless and use UDP.

Multiple choice

Which address is NOT an RFC 1918 address?

  1. 192.168.255.254

  2. 10.9.1.12

  3. 172.17.22.9

  4. 172.32.255.254
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

RFC 1918 defines private address ranges as 10.0.0.0/8, 172.16.0.0/12, and 192.168.0.0/16. 172.32.x.x falls outside the 172.16.0.0/12 range (which ends at 172.31.255.255).