CCNA Certification Preparation Quiz: Networking Concepts and Protocols

1. At which OSI layer are frames checked for errors?

Application

Network

Physical

The data-link layer is responsible for checking each frame received for errors. Every Ethernet frame includes the frame check sequence (FCS) or cyclic redundancy check (CRC) value that is calculated by the host which sent the frame. The receiving host generates its own FCS value for every frame received and then compares it with the FCS included in the frame. If the FCS values match, the frame has arrived without any error. If the FCS values do not match, then it is assumed that the frame has an error or is corrupt and, therefore, is discarded.

Explanation

The data-link layer is responsible for checking each frame received for errors. Every Ethernet frame includes the frame check sequence (FCS) or cyclic redundancy check (CRC) value that is calculated by the host which sent the frame. The receiving host generates its own FCS value for every frame received and then compares it with the FCS included in the frame. If the FCS values match, the frame has arrived without any error. If the FCS values do not match, then it is assumed that the frame has an error or is corrupt and, therefore, is discarded.

2. Identify which of the services below use both TCP and UDP ports:FTPTFTPDNSSSHTELNET.

SSH

FTP

TELNET

DNS is the only service that uses both TCP and UDP ports, while FTP, SSH, and Telnet primarily use only TCP ports for communication.

Explanation

DNS is the only service that uses both TCP and UDP ports, while FTP, SSH, and Telnet primarily use only TCP ports for communication.

3. After carefully examining the network diagram above, select the correct statement regarding broadcast and collision domains:

There is one broadcast domain and seven collision domains.

There are two broadcast domains and 12 collision domains.

There is one broadcast domain and 12 collision domains.

Each link to a switch (switch port) is a separate collision domain in the given diagram. Hubs do not create separate collision domains. Routers create separate broadcast domains.

Explanation

Each link to a switch (switch port) is a separate collision domain in the given diagram. Hubs do not create separate collision domains. Routers create separate broadcast domains.

4. Your manager has requested you indicate which of the above ports will be Spanning Tree Protocol (STP)-designated ports: Switch V1, Port Fa0/0; Switch V3, Port Fa0/0; Switch V3, Port Fa0/24 Switch V1, Port Fa0/24; Switch V2, Port Fa0/0; Switch V2, Port Fa0/24.

Switch V3, Port Fa0/0; Switch V3, Port Fa0/24; Switch V1, Port Fa0/0

Switch V1, Port Fa0/0; Switch V2, Port Fa0/0; Switch V3, Port Fa0/0

Switch V2, Port Fa0/24; Switch V3, Port Fa0/24; Switch V1, Port Fa0/24

The incorrect answers provided do not follow the correct understanding and logic of how Spanning Tree Protocol (STP) works in designating ports. Each incorrect answer violates the principles of STP and would lead to network inefficiencies or potential loops.

Explanation

The incorrect answers provided do not follow the correct understanding and logic of how Spanning Tree Protocol (STP) works in designating ports. Each incorrect answer violates the principles of STP and would lead to network inefficiencies or potential loops.