Three switch functions
Address learning
forward/filter decisions
loop avoidance
The main purpose of the Spanning Tree Protocol in a switched LAN
The main purpose of STP is to prevent switching loops in a network with redundant switched paths.
The states of STP
The purpose of the blocking state is to prevent the use of looped paths.
A port in the listening state prepares to forward data frames without populating the MAC address table.
A port in the learning state populates the MAC address table but doesn't forward data frames.
A port in the forwarding state sends and receives all data frames on the bridged port.
Last, a port in the disabled state is virtually nonoperational.
VLANs break up ________ domains in a Layer 2 switched network.
Broadcast
Switches, by default, only break up ________ domains.
Collisioin
What does trunking provide?
Trunking allows you to make a single port part of multiple VLANs at the same time
You need to power a device, such as an access point or IP phone. What protocol can provide power to these devices over an Ethernet cable?
Power over Ethernet (PoE)
If a frame is received on a switch port and the source MAC address is not in the forward/filter table, what will the switch do?
Flood the frame out all ports except the port it was received on
You plug a host into a switch port, but the user can't get to the services it needs. What is probably the problem?
The VLAN port membership is set wrong
What are the three switch functions at Layer 2?
Address learning, filtering, and loop avoidance
If a frame is received on a switch port and the source MAC address is not in the forward/filter table, what will the switch do?
It will add the source MAC address to the forward/filter table
What is used at Layer 2 to prevent switching loops?
Spanning Tree Protocol (STP)
You need to implement a separate network for contractors and guests working at your office. Which technology should you implement?
Create a VLAN for Contractor and another VLAN for guests
You want to improve network performance by increasing the bandwidth available to hosts and limiting the size of the broadcast domains. Which of the following options will achieve this goal?
Managed hubs
Bridges
Switches
Switches configured with VLANs
By creating and implementing VLANs in your switched network, you can break up broadcast domains at Layer 2. For hosts on different VLANs to communicate, you must have a router or Layer 3 switch.
The types of ports that can found on a switch are___________________ and ___________________. (Choose two.)
VLAN Trunk Protocol
Access
802.1Q
Trunk
Access
Trunk
Hosts are connected to a switch and are members of one VLAN. This is called an access port. Trunk links connect between switches and pass information about all VLANs.
Which switching technology reduces the size of a broadcast domain?
ISL
802.1Q
VLANs
STP
Virtual LANs break up broadcast domains in Layer 2 switched internetworks
Which of the following are the IEEE version of STP? (Choose 2)
802.1x
VLANs
802.1d
802.11
802.1w
802.1d
802.1w
802.1d and 802.1w are both IEEE STP versions, with 802.1w being the latest and greatest version
You connect a host to a switch port, but the new host cannot log into the server that is plugged into the same switch. What could the problem be? (Choose two.)
The router is not configured for the new host.
The STP configuration on the switch is not updated for the new host.
The host has an invalid MAC address.
The switch port the host is connected to is not configured to the correct VLAN membership.
The STP shut down the port
The switch port the host is connected to is not configured to the correct VLAN membership.
The STP shut down the port
Tthe best answers are that the VLAN membership for the port is configured incorrectly and that STP shut down the port.
Which of the following are benefits of VLANs? (Choose three.)
They increase the size of collision domains.
They allow logical grouping of users by function.
They can enhance network security.
They increase the size of broadcast domains while decreasing the number of collision domains.
They simplify switch administration.
They increase the number of broadcast domains while decreasing the size of the broadcast domains.
They allow logical grouping of users by function.
They can enhance network security.
They increase the number of broadcast domains while decreasing the size of the broadcast domains.
VLANs break up broadcast domains in a switched Layer 2 network, which means smaller broadcast domains. They allow configuration by logical function instead of physical location and can create some security if configured correctly.
Which of the following is a Layer 2 protocol used to maintain a loop‐free network?
VTP
STP
RIP
CDP
The Spanning Tree Protocol is used to stop switching loops in a switched network with redundant paths.
What is the result of segmenting a network with a bridge (switch)? (Choose two.)
It increases the number of collision domains.
It decreases the number of collision domains.
It increases the number of broadcast domains.
It decreases the number of broadcast domains.
It makes smaller collision domains.
It makes larger collision domains.
It increases the number of collision domains.
It makes smaller collision domains.
Bridges break up collision domains, which would increase the number of collision domains in a network and also make smaller collision domains.
You connect your host to a switch that is running network analyses software. However, you are not seeing any packets from the server. What do you need to implement on the switch to see all the packet information?
VLANs
STP
Port Mirroring
Authentication
In order to see all frames that pass through the switch and read the packets with a network analyzer, you need to enable port mirroring on the port your diagnostic host is plugged into.
Which of the following features of a switch will allow two switches to pass network information?
PoE
VLANs
Trunking
STP
Trunking allows switches to pass information about many or all VLANs configures on the switches.
What are the distinct functions of Layer 2 switching that increase available bandwidth on the network? (Choose three.)
Address learning
Routing
Forwarding and filtering
Creating network loops
Loop avoidance
IP addressing
Address learning
Forwarding and filtering
Loop avoidance
Layer 2 features include address learning, forwarding and filtering of the network, and loop avoidance
Which of the following statements is true?
A switch creates a single collision domain and a single broadcast domain. A router creates a single collision domain.
A switch creates separate collision domains but one broadcast domain. A router provides a separate broadcast domain.
A switch creates a single collision domain and separate broadcast domains. A router provides a separate broadcast domain as well.
A switch creates separate collision domains and separate broadcast domains. A router provides separate collision domains.
Switches break up collision domains, and routers break up broadcast domains.
What does a switch do when a frame is received on an interface and the destination hardware address is unknown or not in the filter table?
Forwards the switch to the first available link
Drops the frame
Floods the network with the frame looking for the device
Sends back a message to the originating station asking for a name resolution
Switches flood all frames that have an unknown destination address. If a device answers the frame, the switch will update the MAC address table to reflect the location of the device.
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?
Discard it and send an error message back to the originating host
Flood the network with the frame
Add the source address and port to the MAC address table and forward the frame out the destination port
Add the destination to the MAC address table and then forward the frame
Because 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.
Which of the following help isolate network traffic?
hubs
VLANs
Repeaters
Hosts
Virtual LANs help isolate network traffic by breaking up broadcast domains in a layer‐2 switched network
When is STP said to be converged? (Choose two.)
When all ports are in the forwarding state
When all ports are in the blocking state
When all ports are in the Listening state
When all ports are in the Learning state
When all ports are in the forwarding state
When all ports are in the blocking state
The sequence of steps for STP convergence is, by default, blocking, listening, learning, and forwarding. When all ports are in either the blocking or forwarding state, STP is converged.
In which two states is the MAC address table populated with addresses?
Blocked
Listening
Learning
Forwarding
Learning
Forwarding
In the blocked and listening states, the MAC address table is not learning. Only in the learning and forwarding states is the MAC address table learning MAC addresses and populating the MAC address table
You have multiple departments all connected to switches, with cross‐over cables connecting the switches together. However, response time on the network is still very slow because you have upgraded from hubs to switches. What technology should you implement to improve response time on the networks?
STP
VLANs
Convergence
OSPF
Switches break up collision domains by default, but the network is still one large broadcast domain. In order to break up broadcast domains in a Layer 2 switched network, you need to create Virtual LANs.
Why are switches better than hubs in your network by default?
Because they break up broadcast commands by default
Because each port on a switch is a broadcast domain
Because each port on a switch is a collision domain
Because all ports on a hub are broken into broadcast domains by default
Hubs create one collision domain and one broadcast domain. Switches break up collision domains but the network is one large broadcast domain by default.
What is a disadvantage of using port spanning?
It breaks up broadcast domains on all ports
It can create overhead on the switch
It makes the switch one large collision domain
It makes the switch fast between only two ports instead of all ports
Be careful when using port mirroring/spanning on a switch because it can cause a lot of overhead on the switch and possibly crash your network. So, it's a good idea to use this feature at strategic times and only for short periods if possible