Chapter 1 - Introduction To Switched Networks

1. What are the three layers of the switch hierarchial design model? (Choose three.)

Access

Data link

Core

Network access

Enterprise

Distribution

Refer to curriculum topic: 1.1.1
The access layer is the lowest layer and it provides network access to users. The distribution layer has many functions, but it aggregates data from the access layer, provides filtering, policy control, and sets Layer 3 routing boundaries. The core layer provides high speed connectivity.

Explanation

Refer to curriculum topic: 1.1.1
The access layer is the lowest layer and it provides network access to users. The distribution layer has many functions, but it aggregates data from the access layer, provides filtering, policy control, and sets Layer 3 routing boundaries. The core layer provides high speed connectivity.

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2. Refer to the exhibit. A switch receives a Layer 2 frame that contains a source MAC address of 000b.a023.c501 and a destination MAC address of 0050.0fae.75aa. Place the switch steps in the order they occur.

occurs first

occurs second

Refer to curriculum topic: 1.2.1
The first step a switch does when processing a frame is to see if the source MAC address is in the
MAC address table. If the address is not there, the switch adds it. The switch then examines the
destination MAC address and compares it to the MAC address table. If the address is in the table,
the switch forwards the frame out the corresponding port. If the address is missing from the table,
the switch will forward the frame to all ports except the port through which the frame arrived.

Explanation

Refer to curriculum topic: 1.2.1
The first step a switch does when processing a frame is to see if the source MAC address is in the
MAC address table. If the address is not there, the switch adds it. The switch then examines the
destination MAC address and compares it to the MAC address table. If the address is in the table,
the switch forwards the frame out the corresponding port. If the address is missing from the table,
the switch will forward the frame to all ports except the port through which the frame arrived.

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3. When the appropriate switch form factor for a network is being determined, what type of switch should be selected when future expansion is important and cost is not a limiting factor?

Stackable switch

1 rack unit switch

Fixed configuration switch

Modular switch

Refer to curriculum topic: 1.1.2
A modular switch provides fault tolerance and features for bandwidth availability and future expansion by using line cards but is rather costly to implement. Stackable switches provide fault tolerance and bandwidth availability by using special cables between the switches and are less costly to implement than modular switches. A non-stackable switch does not provide these features. A fixed configuration switch is a single switch that does not support features beyond those that originally came with it.

Explanation

Refer to curriculum topic: 1.1.2
A modular switch provides fault tolerance and features for bandwidth availability and future expansion by using line cards but is rather costly to implement. Stackable switches provide fault tolerance and bandwidth availability by using special cables between the switches and are less costly to implement than modular switches. A non-stackable switch does not provide these features. A fixed configuration switch is a single switch that does not support features beyond those that originally came with it.

4. Which function is supplied by the access layer in a three-layer network design?

High-speed connectivity

Routing

Application of policies

Network access

Backbone connectivity

Refer to curriculum topic: 1.1.1
The main purpose of devices in the access layer is to supply network access to end users. Distribution layer devices provide services such as routing and policy functions. The core layer provides high-speed backbone connectivity.

Explanation

Refer to curriculum topic: 1.1.1
The main purpose of devices in the access layer is to supply network access to end users. Distribution layer devices provide services such as routing and policy functions. The core layer provides high-speed backbone connectivity.

5. Which cost-effective physical network topology design is recommended when building a three-tier campus network that connects three buildings?

Bus

Mesh

Extended star

Dual ring

Refer to curriculum topic: 1.1.1
For efficiency, scalability, and cost-effectiveness, building an extended star topology from a centralized site to all other campus sites is recommended. A mesh topology is much more expensive, and bus and dual ring topologies are more difficult to troubleshoot and maintain.

Explanation

Refer to curriculum topic: 1.1.1
For efficiency, scalability, and cost-effectiveness, building an extended star topology from a centralized site to all other campus sites is recommended. A mesh topology is much more expensive, and bus and dual ring topologies are more difficult to troubleshoot and maintain.

6. Which service is provided by an automated attendant feature on a converged network?

Point-to-point video

Call routing

IT management interface

Video conferencing

Refer to curriculum topic: 1.1.1
The automated attendant feature increases the speed of voice services by routing calls directly to
individuals or departments. Pointtopoint
video and video conferencing describe video services on
a converged network. An IT management interface is part of a converged network solution that
allows IT personnel to facilitate moves, adds, and changes through a centralized application.

Explanation

Refer to curriculum topic: 1.1.1
The automated attendant feature increases the speed of voice services by routing calls directly to
individuals or departments. Pointtopoint
video and video conferencing describe video services on
a converged network. An IT management interface is part of a converged network solution that
allows IT personnel to facilitate moves, adds, and changes through a centralized application.

7. Which switching method describes a switch that transfers a frame as soon as the destination MAC address is read?

Fragment-free

Cut-through

Store-and-forward

Latency forwarding

Refer to curriculum topic: 1.2.1

Explanation

Refer to curriculum topic: 1.2.1

8. Refer to the exhibit. The PC that is attached to port Fa0/1 is sending a packet that has a destination MAC address of 0050.0fae.229c. Based on the current S1 MAC address table, what will S1 do first when the packet arrives at the switch?

Forward the data to S2

Broadcast an ARP request to all S1 ports except port Fa0/1

Add the MAC address of the PC that is attached to Fa0/1 to the MAC address table

Broadcast the data to all S1 ports and all S2 ports that have attached end devices

Broadcast the data to all S1 ports that have attached end devices, except the Fa0/1 port

Refer to curriculum topic: 1.2.1
The first step a switch does when processing a frame is to see if the source MAC address is in the
MAC address table. If the address is not there, the switch adds it. The switch then examines the
destination MAC address and compares it to the MAC address table. If the address is in the table,
the switch forwards the frame out the corresponding port. If the address is missing from the table,
the switch will broadcast the frame to all ports except the port through which the frame arrived.

Explanation

Refer to curriculum topic: 1.2.1
The first step a switch does when processing a frame is to see if the source MAC address is in the
MAC address table. If the address is not there, the switch adds it. The switch then examines the
destination MAC address and compares it to the MAC address table. If the address is in the table,
the switch forwards the frame out the corresponding port. If the address is missing from the table,
the switch will broadcast the frame to all ports except the port through which the frame arrived.

9. Which two characteristics describe a converged network? (Choose two.)

Decreased service calls

Support of voice and video both using the same switch

Separate wiring infrastructure for voice and video traffic

Affordability for small and medium businesses

Cheaper equipment cost

Refer to curriculum topic: 1.1.1
Converged networks have traditional user traffic as well as digitized voice and video traffic that once
required separate networks. Now, instead of separate groups managing separate networks, one
group of personnel can manage the network.

Explanation

Refer to curriculum topic: 1.1.1
Converged networks have traditional user traffic as well as digitized voice and video traffic that once
required separate networks. Now, instead of separate groups managing separate networks, one
group of personnel can manage the network.

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10. When an appropriate switch form factor for a network is being determined, what should be selected when fault tolerance and bandwidth availability are desired but the budget is limited?

Stackable switch

Non-stackable switch

Fixed configuration switch

Modular switch

Refer to curriculum topic: 1.1.2
Stackable switches provide fault tolerance and bandwidth availability by using special cables
between switches and are less costly to implement than modular switches. A nonstackable
switch
does not provide these features. A fixed configuration switch is a single switch that does not support
features beyond those that originally came with it. A modular switch usually provides fault tolerance
and features for bandwidth availability but is rather costly to implement.

Explanation

Refer to curriculum topic: 1.1.2
Stackable switches provide fault tolerance and bandwidth availability by using special cables
between switches and are less costly to implement than modular switches. A nonstackable
switch
does not provide these features. A fixed configuration switch is a single switch that does not support
features beyond those that originally came with it. A modular switch usually provides fault tolerance
and features for bandwidth availability but is rather costly to implement.

11. Which option correctly describes a switching method?

Cut-through: makes a forwarding decision after receiving the entire frame

Store-and-forward: forwards the frame immediately after examining its destination MAC address

Cut-through: provides the flexibility to support any mix of Ethernet speeds

Store-and-forward: ensures that the frame is free of physical and data-link errors

Refer to curriculum topic: 1.2.1
Store-and-forward switching performs an error check on an incoming frame after receiving the entire
frame on the ingress port. Switches which use this method have the flexibility to support any mix of
Ethernet speeds. The cut-through method begins the forwarding process after the destination MAC
address of an incoming frame is looked up and the egress port has been determined.

Explanation

Refer to curriculum topic: 1.2.1
Store-and-forward switching performs an error check on an incoming frame after receiving the entire
frame on the ingress port. Switches which use this method have the flexibility to support any mix of
Ethernet speeds. The cut-through method begins the forwarding process after the destination MAC
address of an incoming frame is looked up and the egress port has been determined.

12. Which statement is true about broadcast and collision domains?

Adding a router to the network will increase the size of the collision domain.

The size of the collision domain can be reduced by adding hubs to a network.

The more interfaces a router has the larger the resulting broadcast domain.

Adding a switch to a network will increase the size of the broadcast domain.

Refer to curriculum topic: 1.2.2
A switch that receives a broadcast frame will forward the frame out all other interfaces, including
interfaces that connect to other switches. These switches will also perform the same forwarding
action. By adding more switches to the network, the size of the broadcast domain increases.

Explanation

Refer to curriculum topic: 1.2.2
A switch that receives a broadcast frame will forward the frame out all other interfaces, including
interfaces that connect to other switches. These switches will also perform the same forwarding
action. By adding more switches to the network, the size of the broadcast domain increases.

13. Which two statements about Layer 2 Ethernet switches are true? (Choose two.)

Layer 2 switches prevent broadcasts.

Layer 2 switches have multiple collision domains.

Layer 2 switches route traffic between different networks.

Layer 2 switches decrease the number of broadcast domains.

Layer 2 switches can send traffic based on the destination MAC address.

Refer to curriculum topic: 1.2.2

Explanation

Refer to curriculum topic: 1.2.2

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