If a switch receives a frame and the source MAC address is not in the MAC address table but the destination address is, what will the switch do with the frame?
Options
A. Discard it and send an error message back to the originating host
B. Flood the network with the frame
C. Add the source address and port to the MAC address table and forward the frame out the destination port
D. Add the destination to the MAC address table and then forward the frame
Correct Answer
Add the source address and port to the MAC address table and forward the frame out the destination port
Explanation
Since the source MAC address is not in the MAC address table, the switch will add the source address and the port it is connected to into the MAC address table and then forward the frame to the outgoing port.
Spanning Tree Protocol problems
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1. What is the result of segmenting a network with a bridge (switch)?
Switches, unlike bridges, are hardware based. Cisco says its switches are wire speed and provide low latency, and I guess they are low cost compared to their prices in the 1990s.
3. You have two switches connected together with two crossover cables for redundancy, and STP is disabled. Which of the following will happen between the switches?
Options
A. The routing tables on the switches will not update.
B. The MAC forward/filter table will not update on the switch.
C. Broadcast storms will occur on the switched network.
D. The switches will automatically load-balance between the two links.
Although answer D almost seems right, it is not; the mask is the mask used on the remote network, not the source network. Since there is no number at the end of the static route, it is using the default administrative distance of 1.
6. Which of the following statement is true?
Options
A. A switch creates a single collision domain and a single broadcast domain. A router creates a single collision domain.
B. A switch creates separate collision domains but one broadcast domain. A router provides a separate broadcast domain.
C. A switch creates a single collision domain and separate broadcast domains. A router provides a separate broadcast domain as well.
D. A switch creates separate collision domains and separate broadcast domains. A router provides separate collision domains.
Correct Answer: In an improperly implemented redundant topology
Explanation:
If the Spanning Tree Protocol is not running on your switches and you connect them together with redundant links, you will have broadcast storms and multiple frame copies.
9. Which of the following is a layer 2 protocol used to maintain a loop-free network?
The Spanning Tree Protocol is used to stop switching loops in a switched network with redundant paths.
10. You need to allow one host to be permitted to attach dynamically to each switch interface. Which two commands must you configure on your catalyst switch to meet this policy?
Switch(config-if)# ip access-group 10
Switch(config-if)# switchport port-security maximum 1
The
switchport port-security is an important command, and it's super easy with the CNA; however, from the CLI, you can set the maximum number of MAC addresses allowed into the port, and then set the penalty if this maximum has been passed.