Computer Knowledge

Computer Networks

2,614 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

Refer to the exhibit. The network administrator wants to minimize the number of entries in Router1's routing table. What should the administrator implement on the network?

  1. VLSM

  2. CIDR

  3. Private IP addresses

  4. Classful routing
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

CIDR (Classless Inter-Domain Routing) allows route aggregation by using variable-length subnet masking. This enables network administrators to combine multiple contiguous subnets into single routing table entries, significantly reducing table size. Classful routing maintains separate entries for each network boundary.

Multiple choice

Refer to the exhibit. All routers have been configured with the interface priorities that are shown. All routers were restarted simultaneously. The results of the DR/BDR election are shown. What can be concluded about this network?

  1. Router C cannot win a DR election under any circumstances.

  2. If the link for interface 192.168.1.4 goes down, router B will become the new DR.

  3. The highest router ID was most likely determined via an OSPF router-id statement or statements.

  4. If a new router is added with a higher router ID than router D, it will become the DR.
Reveal answer Fill a bubble to check yourself
C Correct answer
Multiple choice

Refer to the exhibit. This is the debug output from 2 directly connected EIGRP routers. They are not forming an adjacency. What is the cause?

  1. One router is a non-cisco router

  2. They have different autonomous-system numbers

  3. They are using difference sequence numbers

  4. They are sending incorrect hello types
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

EIGRP routers form adjacencies only with neighbors in the same autonomous system (AS). Different AS numbers will cause routers to ignore each other's hello packets, preventing adjacency formation. The debug output shows mismatched AS values, which is a definitive adjacency failure cause.

Multiple choice

Which parameter is used to uniquely identify one wireless network from another?

  1. SSID

  2. OFDM

  3. WEP

  4. DSSS
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The SSID (Service Set Identifier) is a unique name that identifies a specific wireless network. It allows wireless clients to distinguish between multiple available networks in range. Other options (OFDM, WEP, DSSS) are transmission techniques or security protocols, not network identifiers.

Multiple choice

Why is flow control used for TCP data transfer?

  1. To synchronize equipment speed for sent data

  2. To synchronize and order sequence numbers so data is sent in complete numerical order

  3. To prevent the receiver from being overwhelmed by incoming data

  4. To synchronize window size on the server

  5. To simplify data transfer to multiple hosts
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

TCP flow control prevents a fast sender from overwhelming a slower receiver. The receiver advertises its available buffer space in the TCP header (window size), and the sender limits transmission accordingly. This prevents packet loss and ensures reliable delivery.

Multiple choice

Which of the following statements describes the bounded updates used by EIGRP?

  1. Bounded updates are sent to all routers within an autonomous system.

  2. Partial updates are sent only to routers that need the information.

  3. The updates are sent to all routers in the routing table.

  4. Updates are bounded by the routers in the topology table.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

EIGRP sends bounded (partial) updates only to routers affected by a topology change, not to all routers in the autonomous system. This conserves bandwidth and speeds convergence by limiting unnecessary processing. Updates propagate only where needed through the EIGRP topology table.

Multiple choice

Which hierarchical design model layer controls the flow of network traffic using policies and delineates broadcast domains by performing routing functions between virtual LANs (VLANs)?

  1. Application

  2. Access

  3. Distribution

  4. Network

  5. Core
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The distribution layer is the hierarchical layer that implements policies, performs routing between VLANs, and controls traffic flow between access and core layers. It aggregates access layer connections and applies ACLs, QoS policies, and broadcast domain segmentation through inter-VLAN routing.

Multiple choice

Refer to the exhibit. What can be concluded about the function of the Serial 0/0/0 interface on the router after the commands are entered?

  1. All username and password information that is sent will be encrypted.

  2. All authentication on the serial link will be accomplished using a two-way handshake.

  3. The Predictor algorithm will be used to compress all packets that are sent and received on the serial link.

  4. The serial link will be closed if the number of received packets at the destination node falls below 90 percent of the packets that are sent.
Reveal answer Fill a bubble to check yourself
D Correct answer
Multiple choice

Why is it advisable that a network administrator use SSH instead of Telnet when managing switches?

  1. SSH uses TCP whereas Telnet does not.

  2. SSH encrypts only the username and password when logging in.

  3. SSH encrypts all remote management communications whereas Telnet does not.

  4. SSH sends a clear text message steam which reduces the bandwidth use for management.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

SSH encrypts the entire management session including all commands, output, and authentication credentials. Telnet transmits everything in clear text, making passwords and configuration visible to packet sniffers. SSH provides confidentiality and integrity for remote device management.

Multiple choice

Refer to the exhibit. Branch A has a non-Cisco router that is using IETF encapsulation and Branch B has a Cisco router. After the commands that are shown are entered, R1 and R2 fail to establish the PVC. The R2 LMI is Cisco, and the R1 LMI is ANSI. The LMI is successfully established at both locations. Why is the PVC failing?

  1. The PVC to R1 must be point-to-point.

  2. LMI types must match on each end of a PVC.

  3. The frame relay PVCs cannot be established between Cisco and non-Cisco routers.

  4. The IETF parameter is missing from the frame-relay map ip 10.10.10.1 201 command.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

When connecting Cisco to non-Cisco routers over Frame Relay, IETF encapsulation must be specified explicitly in the frame-relay map statement on the Cisco side. The default Cisco encapsulation is incompatible with IETF-only peers, causing PVC establishment failure despite successful LMI.

Multiple choice

Which method is most effective in protecting the routing information that is propagated between routers on the network?

  1. Disable IP source routing.

  2. Configure passive interfaces.

  3. Configure routing protocol authentication.

  4. Secure administrative lines with Secure Shell.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Routing protocol authentication (such as MD5 authentication for OSPF, EIGRP, or BGP) cryptographically verifies routing updates between routers, preventing unauthorized or malicious route injection. Disabling IP source routing and using SSH for administrative access are good security practices but don't protect routing information itself. Passive interfaces prevent routing updates on specified interfaces but don't authenticate the updates that are sent.

Multiple choice

UDP is not used for which of the following protocols?

  1. Domain Name System

  2. Network Time Protocol

  3. Remote Procedure Call

  4. File Transfer Protocol

  5. Real Time Streaming Protocol
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

File Transfer Protocol (FTP) is a standard network protocol used to transfer files from one host to another host over a TCP-based network, such as the Internet.

Multiple choice

Which of the following protocols allows location independent routing of IP datagrams on the Internet?

  1. Open shortest path first

  2. Vertical handover

  3. Roaming

  4. Locator/Identifier separation protocol

  5. Mobile IP
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

The Mobile IP protocol allows location-independent routing of IP datagrams on the Internet. Each mobile node is identified by its home address disregarding its current location in the Internet. While away from its home network, a mobile node is associated with a care-of address which identifies its current location and its home address is associated with the local endpoint of a tunnel to its home agent. Mobile IP specifies how a mobile node registers with its home agent and how the home agent routes datagrams to the mobile node through the tunnel.