Communicating over the Network

apprehensiveheehawNetworking and Communications

Oct 26, 2013 (3 years and 10 months ago)

163 views

思科网络技术学院理事会
.

http://www.catc.edu.cn

1

Communicating over the Network

Network Fundamentals


Chapter 2

2

思科网络技术学院理事会
.

http://www.catc.edu.cn

Modified by Ye,
Haisong
. yhs.shnu@gmail.com

Objectives


Describe the structure of a network, including the
devices and media that are necessary for successful
communications.


Explain the function of protocols in network
communications.


Explain the advantages of using a layered model to
describe network functionality.


Describe the role of each layer in two recognized
network models: The TCP/IP model and the OSI
model.


Describe the importance of addressing and naming
schemes in network communications.

3

思科网络技术学院理事会
.

http://www.catc.edu.cn

Modified by Ye,
Haisong
. yhs.shnu@gmail.com

Context Index

2.3 The Platform for Communications

2.4 LANs, WANs, and Internetworks

2.5 Protocols

2.4 Using Layered Models

2.5 Network Addressing


思科网络技术学院理事会
.

http://www.catc.edu.cn

4

2.3 The Platform for Communications

5

思科网络技术学院理事会
.

http://www.catc.edu.cn

Modified by Ye,
Haisong
. yhs.shnu@gmail.com

2.3.1 The Elements of Communication


Data or information networks capable of carrying many
different types of communications


3 common elements of communication



message source



the channel



message destination

6

思科网络技术学院理事会
.

http://www.catc.edu.cn

Modified by Ye,
Haisong
. yhs.shnu@gmail.com

2.3.2 Communicating the Messages


Segmentation
-

breaking communication into pieces.

7

思科网络技术学院理事会
.

http://www.catc.edu.cn

Modified by Ye,
Haisong
. yhs.shnu@gmail.com

2.3.2 Communicating the Messages


Multiplexing


interleaving the pieces as they traverse
the media.

8

思科网络技术学院理事会
.

http://www.catc.edu.cn

Modified by Ye,
Haisong
. yhs.shnu@gmail.com

2.3.2 Communicating the Messages


Multiple pieces are labeled for easy direction and re
-
assembly. Labeling provides for ordering and
assembling the pieces when they arrive.

9

思科网络技术学院理事会
.

http://www.catc.edu.cn

Modified by Ye,
Haisong
. yhs.shnu@gmail.com

2.3.3 Components of the Network


Devices and media
are the physical elements or
hardware of the network.


Devices


10

思科网络技术学院理事会
.

http://www.catc.edu.cn

Modified by Ye,
Haisong
. yhs.shnu@gmail.com

2.3.3 Components of the Network


Devices and media are the physical elements or
hardware of the network.


Media


11

思科网络技术学院理事会
.

http://www.catc.edu.cn

Modified by Ye,
Haisong
. yhs.shnu@gmail.com

2.3.3 Components of the Network


Services
and
processes

are the communication
programs, called software, that run on the networked
devices.

12

思科网络技术学院理事会
.

http://www.catc.edu.cn

Modified by Ye,
Haisong
. yhs.shnu@gmail.com

2.3.4 End Devices and their Role on the Network


Some examples of end devices are:


Computers (work stations, laptops, file servers, web servers)


Network printers


VoIP phones


Security cameras


Mobile handheld devices (such as wireless barcode scanners,
PDAs)

13

思科网络技术学院理事会
.

http://www.catc.edu.cn

Modified by Ye,
Haisong
. yhs.shnu@gmail.com

2.3.5 Intermediary Devices and their Role on the Network


These devices connect the individual hosts to the
network and can connect multiple individual networks to
form an internetwork. Examples of intermediary
network devices are:


Network Access Devices (Hubs, switches, and wireless
access points)


Internetworking Devices (routers)


Communication Servers and Modems


Security Devices (firewalls)

14

思科网络技术学院理事会
.

http://www.catc.edu.cn

Modified by Ye,
Haisong
. yhs.shnu@gmail.com

2.3.5 Intermediary Devices and their Role on the Network


Processes running on the intermediary network devices
perform these functions:


Regenerate and retransmit data signals


Maintain information about what pathways exist through the
network and internetwork


Notify other devices of errors and communication failures


Direct data along alternate pathways when there is a link failure


Classify and direct messages according to
QoS

priorities


Permit or deny the flow of data, based on security settings

15

思科网络技术学院理事会
.

http://www.catc.edu.cn

Modified by Ye,
Haisong
. yhs.shnu@gmail.com

2.3.6 Network Media


Modern networks primarily use three types of media to
interconnect devices and to provide the pathway over
which data can be transmitted. These media are:


Wireless transmission

16

思科网络技术学院理事会
.

http://www.catc.edu.cn

Modified by Ye,
Haisong
. yhs.shnu@gmail.com

2.3.6 Network Media


Copper and Fiber Optics


Metallic wires within cables


Glass or plastic fibers (fiber optic cable)


思科网络技术学院理事会
.

http://www.catc.edu.cn

17

2.4 LANs, WANs, and Internetworks

18

思科网络技术学院理事会
.

http://www.catc.edu.cn

Modified by Ye,
Haisong
. yhs.shnu@gmail.com

2.4.1 Local Area Networks


A network serving a home, building or campus is
considered a Local Area Network (LAN)


Networks infrastructures can vary greatly in terms of:


The size of the area covered


The number of users connected


The number and types of services available

19

思科网络技术学院理事会
.

http://www.catc.edu.cn

Modified by Ye,
Haisong
. yhs.shnu@gmail.com

2.4.2 Wide Area Networks


LANs separated by geographic distance are connected
by a network known as a Wide Area Network (WAN)



20

思科网络技术学院理事会
.

http://www.catc.edu.cn

Modified by Ye,
Haisong
. yhs.shnu@gmail.com

2.4.3 The Internet
-

A Network of Networks


The internet is defined as a global mesh of
interconnected networks.


LANs and WANs may be connected into internetworks.

21

思科网络技术学院理事会
.

http://www.catc.edu.cn

Modified by Ye,
Haisong
. yhs.shnu@gmail.com

2.4.4 Network Representations


Important terms to remember are:


Network Interface Card


Physical Port


Interface

PT
Activity 2.2.4.2

思科网络技术学院理事会
.

http://www.catc.edu.cn

22

2.5 Protocols

23

思科网络技术学院理事会
.

http://www.catc.edu.cn

Modified by Ye,
Haisong
. yhs.shnu@gmail.com

2.5.1 Rules that Govern Communications


The importance of protocols and how they are used to
facilitate communication over data networks

A protocol is a set of predetermined rules


24

思科网络技术学院理事会
.

http://www.catc.edu.cn

Modified by Ye,
Haisong
. yhs.shnu@gmail.com

2.5.2 Network Protocols


Network protocols are used to allow devices to
communicate successfully.


Protocols provide the format or structure of the message


25

思科网络技术学院理事会
.

http://www.catc.edu.cn

Modified by Ye,
Haisong
. yhs.shnu@gmail.com

2.5.2 Network Protocols


Protocols provide the
process by which
networking devices
share information about
pathways with other
networks.

26

思科网络技术学院理事会
.

http://www.catc.edu.cn

Modified by Ye,
Haisong
. yhs.shnu@gmail.com

2.5.2 Network Protocols


Protocols provide how
and when error and
system messages are
passed between
devices.

27

思科网络技术学院理事会
.

http://www.catc.edu.cn

Modified by Ye,
Haisong
. yhs.shnu@gmail.com

2.5.2 Network Protocols


Protocols provide
the setup and
termination of data
transfer sessions.

28

思科网络技术学院理事会
.

http://www.catc.edu.cn

Modified by Ye,
Haisong
. yhs.shnu@gmail.com

2.5.3 Protocol Suites and Industry Standards


A standard is a process or protocol that has been
endorsed by the networking industry and ratified by a
standards organization.


29

思科网络技术学院理事会
.

http://www.catc.edu.cn

Modified by Ye,
Haisong
. yhs.shnu@gmail.com

2.5.4 The Interaction of Protocols


An example of the use of a protocol suite in network
communications is the interaction between a web
server and a web browser.

30

思科网络技术学院理事会
.

http://www.catc.edu.cn

Modified by Ye,
Haisong
. yhs.shnu@gmail.com

2.5.5 Technology Independent Protocols


Networking protocols describe the functions that occur
during network communications.


Many diverse types of devices can communicate using
the same sets of protocols. This is because protocols
specify network functionality, not the underlying
technology to support this functionality.

思科网络技术学院理事会
.

http://www.catc.edu.cn

31

2.6 Using Layered Models

32

思科网络技术学院理事会
.

http://www.catc.edu.cn

Modified by Ye,
Haisong
. yhs.shnu@gmail.com

2.6.1 The Benefits of Using a Layered Model


Assists in protocol design


Fosters competition


Changes in one layer do not affect other layers


Provides a common language


33

思科网络技术学院理事会
.

http://www.catc.edu.cn

Modified by Ye,
Haisong
. yhs.shnu@gmail.com

2.6.2 Protocol and Reference Models


There are two basic types of networking models:
protocol models and reference models.

34

思科网络技术学院理事会
.

http://www.catc.edu.cn

Modified by Ye,
Haisong
. yhs.shnu@gmail.com

2.6.3 The TCP/IP Model

35

思科网络技术学院理事会
.

http://www.catc.edu.cn

Modified by Ye,
Haisong
. yhs.shnu@gmail.com

2.6.4 The Communication Process


A complete communication process includes
these steps:

1.
Creation of data
at the application layer of the originating source
end device

2.
Segmentation and encapsulation
of data as it passes down the
protocol stack in the source end device

3.
Generation of the data
onto the media at the network access layer
of the stack

4.
Transportation of the data
through the internetwork, which
consists of media and any intermediary devices

5.
Reception of the data
at the network access layer of the destination
end device

6.
Decapsulation

and reassembly
of the data as it passes up the
stack in the destination device

7.
Passing this data to the destination application
at the
Application layer of the destination end device

36

思科网络技术学院理事会
.

http://www.catc.edu.cn

Modified by Ye,
Haisong
. yhs.shnu@gmail.com

2.6.5 Protocol Data Units and Encapsulation


Encapsulation


37

思科网络技术学院理事会
.

http://www.catc.edu.cn

Modified by Ye,
Haisong
. yhs.shnu@gmail.com

2.6.6 The Sending and Receiving Process


The process of sending and receiving messages.

OSI Process

38

思科网络技术学院理事会
.

http://www.catc.edu.cn

Modified by Ye,
Haisong
. yhs.shnu@gmail.com

2.6.7 The OSI Model

39

思科网络技术学院理事会
.

http://www.catc.edu.cn

Modified by Ye,
Haisong
. yhs.shnu@gmail.com

2.6.8 Comparing the OSI Model with the TCP/IP Model


Compare OSI and TCP/IP model


思科网络技术学院理事会
.

http://www.catc.edu.cn

40

2.7 Network Addressing

41

思科网络技术学院理事会
.

http://www.catc.edu.cn

Modified by Ye,
Haisong
. yhs.shnu@gmail.com

2.7.1 Addressing in the Network


It is critical for each piece of data to contain enough
identifying information to get it to the correct destination.


There are various types of addresses that must be
included to successfully deliver the data from a source
application running on one host to the correct
destination application running on another.


42

思科网络技术学院理事会
.

http://www.catc.edu.cn

Modified by Ye,
Haisong
. yhs.shnu@gmail.com

2.7.2 Getting the Data to the End Device


The PDUs contain Ethernet MAC Addresses, IP
Addresses, and TCP/UDP Port numbers


43

思科网络技术学院理事会
.

http://www.catc.edu.cn

Modified by Ye,
Haisong
. yhs.shnu@gmail.com

2.7.3 Getting the Data through the Internetwork


Getting the Pieces to the Correct Network.

44

思科网络技术学院理事会
.

http://www.catc.edu.cn

Modified by Ye,
Haisong
. yhs.shnu@gmail.com

2.7.4 Getting the Data to the Right Application


Information in the encapsulation header is used to
identify the source and destination processes for data
communication


45

思科网络技术学院理事会
.

http://www.catc.edu.cn

Modified by Ye,
Haisong
. yhs.shnu@gmail.com

Summary

46

思科网络技术学院理事会
.

http://www.catc.edu.cn

Modified by Ye,
Haisong
. yhs.shnu@gmail.com