Communicating over the network

Communicating Over the Network

The Platform for Communications

Elements of Communication

People communicate in many different ways.
Vocal, a look, a

Elements of Communication

Devices communicate in exactly the same way.

Communicating the Messages

In theory, a network communication could be sent as one continuous stream of

Communicating the Messages

A better approach is called Segmentation.
The data stream is divided into smaller, more

Communicating the Messages

Segmentation and Reliability:
Increases the reliability of network communications.
Separate

Communicating the Messages

Segmentation Disadvantage: Added level of complexity.
The label is a

Components of the Network

End Devices

Work Stations, Servers, Laptops, Printers, VoIP Phones, Security Cameras, PDAs......
Any

End Devices

End Devices:
A host can be a client, a server or both.
The software installed

Intermediary Devices

Routers, Switches, Hubs, Wireless Access Points, Communication Servers, Security Devices.
Any

Intermediary Devices

Manage data as it flows through the network.
Some use the

Intermediary Devices

Regenerate and retransmit data signals.
Maintain information about what pathways exist

Media

The medium provides the channel over which the messages travel from

Media

The signal encoding that must occur is different for each type

Media

Different network media have different features and benefits.
Not all network media

Communicating Over the Network

LANs, WANs and Internetworks

Local Area Networks

An individual network usually spans a single geographical area,

Wide Area Networks

Networks that connect LANs in geographically separated locations. Usually

The Internet : A Network of Networks

Internet Service Providers (ISPs) connect

Network Representations

Specialized terminology is used to describe how these devices and

Network Representations

Network Interface Card (NIC):
Provides the physical connection to the network at the

Network Representations

Interface:
Specialized ports on an internetworking device that connect to individual

Communicating Over the Network

Protocols

Rules That Govern Communications

Protocols:
Are the rules that govern communications.

The format or

Protocol Suites

Protocol Suite:
A group of inter-related protocols that are necessary to

Interaction of Protocols

Technology Independent Protocols

Protocols are not dependent upon any specific technology.
They describe

Communicating Over the Network

Using Layered Models

Layered Models

Layered models separate the functions of specific protocols.

Benefits of a Layered Model

Benefits of a Layered Model:
Have defined information

Protocol and Reference Models

Protocol Model:
Closely matches the structure of a particular protocol

Protocol and Reference Models

Reference Model:
Provides a common reference for maintaining consistency within all

TCP/IP Model

Open Standard
No one company controls it.
Governed by IETF Working Groups
Standards proposed using Request for Comments

Request For Comments RFC

The Communication Process

Protocol Data Units and Encapsulation

Header

Header

Data

Header

Trailer

0010100111011001010000011111010100010101

Segmentation and Encapsulation

Protocol Data Units and Encapsulation

Header

Header

Header

Trailer

Decapsulation and Reassembly

Data

0010100111011001010000011111010100010101

Protocol Data Units and Encapsulation

Header

Header

Header

Trailer

Email Message

Data

Data

Data

Protocol Data Units

Data

Segment

Packet

Frame

Protocol Data Units and Encapsulation

Communicating Over the Network

The OSI Model

OSI Model

The International Organization for Standardization (ISO) released the Open Systems

OSI Model

Breaks network communication into smaller, more manageable parts.
Makes learning it

OSI Model - Example - FYI

Descriptive Scheme: Can be used to

OSI Model – Example - FYI

Descriptive Scheme: Can be used to

OSI Model – Example - FYI

Descriptive Scheme: Can be used to

OSI Model

OSI Model

Primary concern: Communications between applications

Primary concern: Moving raw data cross

Communicating Over the Network

Network Addressing

OSI Model

Getting Data to the End Device

Header

Header

Header

Trailer

Email Message

Data

Data

Data

Encoded Data

Process

Logical

Physical

Encapsulation Process and Addressing

1.

2.

3.

4.

5.

6.

7.

Addressing

Getting Data to the End Device

1.

2.

3.

4.

5.

6.

7.

Layer 2 Addressing

Delivery on a single

Getting Data to the End Device

Layer 2 Header

Getting Data Through The Network

1.

2.

3.

4.

5.

6.

7.

Layer 3 Addressing

Move data from one local

Getting Data Through the Network

Layer 2 Header

Layer 3 Header

Getting Data to the Right Application

1.

2.

3.

4.

5.

6.

7.

Layer 4 Addressing

Identifies the specific process

Getting Data to the Right Application

Layer 2 Header

Layer 3 Header

Layer 4

Putting It All Together

Logical

MAC

Port

MAC

Comparing the OSI and TCP/IP Models