Written Labs

In this section, you will complete the following written labs:

• Lab 1.1: Switching Definitions

• Lab 1.2: Cisco’s Three-Layer Model

• Lab 1.3: Switching Theory

Lab 1.1: Switching Definitions

In the following table, the first column contains definitions of different types of switching. Fill in the second column with the number or numbers of the correct switching technology.

1. Layer 2 switching

2. Layer 3 switching

3. Layer 4 switching

4. Multi-layer switching

   Definition	Switching Type
   Based on “route once, switch many”
   Enables prioritization based on specific applications
   Creates security by using source or destination addresses and port numbers
   Can use NetFlow switching
   Enables you to create flatter networks
   Builds a filtering table based on application port numbers
   Communicates with peer layers in a different system with packets
   Reads the TCP and UDP port fields for filtering and forwarding information
   Uses access lists to control traffic
   Uses hardware-based routing
   Uses hardware-based bridging
   Uses an ASIC to handle frame forwarding
   Provides both layer 2 and layer 3 functions

Answers to Lab 1.1

Definition	Numbered Answer
Based on “route once, switch many”	4
Enables prioritization based on specific applications	3
Creates security by using source or destination addresses and port numbers	3
Can use NetFlow switching	2, 3
Enables you to create flatter networks	1
Builds a filtering table based on application port numbers	3
Communicates with peer layers in a different system with packets	2
Reads the TCP and UDP port fields for filtering and forwarding information	3
Uses access lists to control traffic	2, 3
Uses hardware-based routing	2
Uses hardware-based bridging	1
Uses an ASIC to handle frame forwarding	1, 2
Provides both layer 2 and layer 3 functions	4

Lab 1.2: Cisco’s Three-Layer Model

Options 1, 2, and 3 are the layers in the Cisco three-layer model. Match the functions to the correct layer.

1. Access layer

2. Distribution layer

3. Core layer

   Function	Layer
   Routes traffic between VLANs
   Uses collision domains
   Uses broadcast domains
   Uses access lists
   Provides end users with access to the network
   Communicates between the switch blocks and to the enterprise servers
   Switches traffic as quickly as possible

Answers to Lab 1.2

Function	Layer
Routes traffic between VLANs	2
Uses collision domains	1
Uses broadcast domains	2
Uses access lists	2
Provides end users with access to the network	1
Communicates between the switch blocks and to the enterprise servers	3
Switches traffic as quickly as possible	3

Lab 1.3: Switching Theory

Write the answers to the following questions:

1.	Which device is used to break up broadcast domains?
2.	Which device is used to break up collision domains?
3.	What are the units of data at the lowest four layers of the OSI model, in top-to-bottom order?
4.	Which Cisco layer is used to pass traffic as quickly as possible?
5.	What is the Protocol Data Unit (PDU) used at the Transport layer?
6.	What is the PDU used at the Network layer?
7.	Which Cisco layer is used to break up collision domains?
8.	Which OSI layer creates frames by encapsulating packets with a header and trailer?
9.	What devices provide multicast control and packet-based security?
10.	What breaks up broadcast domains in a layer 2 switched network?

Answers

1.	A layer 3 device, usually a router. Layer 2 devices do not break up broadcast domains.
2.	A layer 2 device, typically a switch. Although routers break up both collision domains and broadcast domains, layer 2 switches are primarily used to break up collision domains.
3.	Segment, packet, frame, bits. It is important to understand the question. This question asked for the units of data, which shows how data is encapsulated as user data goes from the Application layer down to the Physical layer.
4.	The core layer should have no packet manipulation, if possible.
5.	Segments are the name for the PDU used at the Transport layer.
6.	A packet or datagram is the PDU used at the Network layer.
7.	Access layer. Remember, the distribution layer is used to break up broadcast domains, and the access layer is used to break up collision domains.
8.	Data Link. Data is encapsulated with header and trailer information at the Data Link layer.
9.	Routers or layer 3 devices are the only devices that control broadcasts and multicasts, as well as providing packet filtering.
10.	Virtual LANs. These are configured on the layer 2 switches, and layer 3 devices provide a means for moving traffic between the VLANs.