1. Network Communication Overview
Purpose: This chapter reviews general networking theory and introduces students to some of Cisco’s product line.
Timing: This chapter takes approximately 1.5 hours to present.
Note: This section has a product selection tool laboratory exercise at the end.
Contents:
Objectives—This section explains what the student will be able to do at the end of this chapter.
Defining Network Components—This section displays where devices are placed in the network.
Mapping Business Needs to a Hierarchical Model—This section describes the heirarchical model used in network design.
OSI Model Overview—This section reviews the OSI model.
Communicating Between Layers—This section describes encapsulation and de-encapsulation.
Written Exercise 1—This section has a written exercise to test the students’ knowledge of the OSI model.
Physical Layer Functions—This section describes the physical layer of the OSI Model.
Data Link Layer Functions—This section describes the data link layer of the OSI Model.
Network Layer Functions—This section describes the network layer of the OSI Model.
Transport Layer Functions—This section describes the transport layer of the OSI Model.

2. Network Communication Topics
Packet delivery process
OSI model overview
Purpose: this figure states the chapter objectives.
Emphasize: Read or state each objective so each student has a clear understanding of the chapter objectives.

3. Packet Delivery Process
Data package assembled
Packet addressed
Packet placed on medium
Purpose: this figure states the chapter objectives.
Emphasize: Read or state each objective so each student has a clear understanding of the chapter objectives.

4. OSI Model Overview Application Application (Upper) Layers Presentation
Session
Layer 1 of 2:
Purpose: This figure orients the students to the OSI model.
Emphasize:
This model should be a review for students who attend this course. Gage the depth of your discussion around the knowledge of the students.
Transition: The following layer discusses the lower layers of the OSI reference model.

5. OSI Model Overview Application (Upper) Layers Presentation Session
Transport Layer
Layer 2 of 2:
Purpose: This figure orients the students to the next set of concepts.
Emphasize:
The Data Link layer of the OSI reference model is implemented by Switches and Bridges. These devices encapsulate date in “frames”.
The Network layer of the OSI reference model is implemented by Routers. These devices encapsulate data in ‘packets’.
The Transport layer of the OSI reference model is implemented by various protocols; one of which is TCP. TCP uses ports and encapsulates the data in ‘segments’.
Network Layer
Data Flow
Layers
Data Link
Physical

6. Role of Application Layers
EXAMPLES
Telnet
HTTP
Application
Network services
Slide 1 of 4:
Purpose: This figure orients the students to the application layer.
Emphasize:
This layer discusses network applications rather than computer applications. So, applications such as spreadsheets, word processors, or presentation graphics are not the applications being described here. Network applications may be applications that support, electronic mail, file transfer, remote access, network management, and so on.
Transition: The following discusses the presentation layer.

7. Role of Application Layers
EXAMPLES
Telnet
HTTP
Application
Network services
ASCII
EBCDIC
JPEG
Presentation
How data is presented
Slide 2 of 4:
Purpose: This figure orients the students to the presentation layer.
Emphasize:
This layer discusses code formatting, data presentation standards, and conversion.
Transition: The following discusses the session layer.

8. Role of Application Layers
EXAMPLES
Telnet
HTTP
Application
Network services
ASCII
EBCDIC
JPEG
Presentation
How data is presented
Keeping different applications’
data separate
Session
Slide 3 of 4:
Purpose: This figure orients the students to the session layer.
Emphasize:
This layer coordinates applications as they interact on different hosts. Examples of session-layer protocols include: NFS, SQL, RPC, and so on.
Transition: The following displays the lower layers.
Sockets

9. Role of Application Layers
EXAMPLES
Telnet
HTTP
ASCII
EBCDIC
JPEG
Sockets
Application
Network services
Presentation
How data is presented
Keeping different applications’
data separate
Session
Slide 4 of 4:
Purpose: This figure orients the students to the entire OSI model stack.
Emphasize:
The lower layers sit below the upper three layers. The remainder of this course is focused on the lower layers.
Transition: The following discusses the physical layer of the OSI reference model.
Transport Layer
Network Layer
Data Link
Physical

10. Role of Data Flow Layers
EXAMPLES
Slide 1 of 5
Purpose: This figure orients the students to the physical layer of the OSI Model.
Emphasize:
The physical layer specifies the electrical, mechanical procedural, and functional requirements for activating, maintaining, and deactivating the physical link between systems.
Certain physical standards are associated with certain data link standards. For example, is used with data link standard for Ethernet. It is not used in WAN connections. This is covered more in-depth later in the course.
Transition: The following discusses Layer 2, the Data Link layer, of the OSI reference model.
Move bits between devices
Specifies voltage, wire speed and cable pin-outs
Ethernet
cable
Physical

11. Role of Data Flow Layers
EXAMPLES
Slide 2 of 5:
Purpose: This figure orients the students to the data link layer.
Emphasize:
The data link layer provides data transport across a physical link is and physical and data link Ethernet protocol. It is used with the standard.
Transition: The following discusses Layer 3, the network layer, of the OSI reference model.
Device addressing
Media Access Control
Ethernet driver
Data Link
Move bits between devices
Specifies voltage, wire speed and cable pin-outs
Ethernet
cable
Physical

12. Role of Data Flow Layers
EXAMPLES
Logical addressing
Routing
Network IP
Slide 3 of 5:
Purpose: This figure orients the students to the network layer.
Emphasize:
Network layer is where IP occurs.
Transition: The following discusses Layer 4, the transport layer, of the OSI reference model.
Device addressing
Media Access Control
Data Link
Ethernet driver
Move bits between devices
Specifies voltage, wire speed and cable pin-outs
Physical
Ethernet
cable

13. Role of Data Flow Layers
EXAMPLES
Reliable or unreliable delivery
Segmentation
TCP
UDP
Transport
Logical addressing
Routing
Network IP
Slide 4 of 5:
Purpose: This figure orients the students to the transport layer.
Emphasize:
The Transport layer of the OSI reference model is implemented by various protocols; one of which is TCP. TCP uses ports and encapsulates the data in ‘segments’. TCP is connection oriented so it offers reliable service. The other major transport layer protocol discussed in this course is UDP. It offers speed but no reliability because it is connectionless.
Transition: The following presents the entire OSI stack again.
Device addressing
Media Access Control
Data Link
Ethernet driver
Move bits between devices
Specifies voltage, wire speed and pin-out cables
Physical
Ethernet
cable

14. Role of Data Flow Layers
Application
Presentation
EXAMPLES
Session
Reliable or unreliable delivery
Segmentation
TCP
UDP
Transport
Logical addressing
Routing
Network IP
Slide 4 of 5:
Purpose: This figure orients the students to the transport layer.
Emphasize:
The Transport layer of the OSI reference model is implemented by various protocols; one of which is TCP. TCP uses ports and encapsulates the data in ‘segments’. TCP is connection oriented so it offers reliable service. The other major transport layer protocol discussed in this course is UDP. It offers speed but no reliability because it is connectionless.
Transition: The following presents the entire OSI stack again.
Device addressing
Media Access Control
Data Link
Ethernet driver
Move bits between devices
Specifies voltage, wire speed and pin-out cables
Physical
Ethernet
cable

15. Encapsulating Data PDU Segment Transport Network Packet Data Link
Application
Presentation
PDU
Session
Upper Layer Data
Segment
Transport
TCP Header
Upper Layer Data
Network
Packet
IP Header
Data
Purpose: This figure illustrates encapsulation.
Emphasize: The protocol data units (PDUs) are the terms used in the industry and in this course to describe data at the different layers.
Encapuslation is a key concept that illustrates how data is formatted prior to being sent across a link. This example is an illustration is Ethernet (or token ring) at the data link and physical layer and TCP/IP at the network and transport layers.
Transition: The following discusses de-encalsulation.
Data Link
Frame
MAC Header
Data
FCS
Physical
Bits

16. De-encapsulating Data IP + TCP + Upper Layer Data
Application
Presentation
Session
Upper Layer Data
Transport
Upper Layer Data
TCP Header
Network
TCP+ Upper Layer Data
Purpose: This figure illustrates de-encapsulation.
Emphasize: At the destination, the headers at each layer are stripped off as the data moves back up the stack.
IP Header
IP + TCP + Upper Layer Data
Data Link
LLC/MAC Header
Physical

17. Functional Responsibilities
Written Exercise: OSI Model
OSI Model
PDU
Functional Responsibilities
Examples
Application
Presentation
Session
Transport
Purpose: This exercise is intended to re-enforce students understanding of the OSI model.
Note: Students should fill in the empty spaces to complete the table.
Answers are in the “Answers” appendix.
Network
Data Link
Physical