思科网络技术学院理事会. 1 OSI Physical Layer Network Fundamentals – Chapter 8

2 思科网络技术学院理事会. Objectives  Explain the role of Physical layer protocols and services in supporting communication across data networks. - Describe the role of signals used to represent bits as a frame as the frame is transported across the local media  Describe the purpose of Physical layer signaling and encoding as they are used in networks  Identify the basic characteristics of copper, fiber and wireless network media  Describe common uses of copper, fiber and wireless network media

3 思科网络技术学院理事会. Context Index  8.1 The Physical Layer – Communication Signals  8.2 Physical Signaling and Encoding: Representing Bits  8.3 Physical Media – Connecting Communication  8.4 Labs – Media Connectors

思科网络技术学院理事会 The Physical Layer – Communication Signals

5 思科网络技术学院理事会 Physical Layer - Purpose  The OSI Physical layer provides the means to transport across the network media the bits that make up a Data Link layer frame.

6 思科网络技术学院理事会 Physical Layer - Purpose  The purpose of the Physical layer is to create the electrical, optical, or microwave signal that represents the bits in each frame.

7 思科网络技术学院理事会 Physical Layer - Operation  There are three basic forms of network media on which data is represented: － Copper cable － Fiber － Wireless

8 思科网络技术学院理事会 Physical Layer - Standards  Comparison of Physical layer standards and upper layer standards

9 思科网络技术学院理事会 Physical Layer - Standards  Standards for the Physical layer specify signal, connector, and cabling requirements.

10 思科网络技术学院理事会 Physical Layer - Standards  Standards for the Physical layer specify signal, connector, and cabling requirements.

11 思科网络技术学院理事会 Physical Layer - Standards  Standards for the Physical layer specify signal, connector, and cabling requirements.

12 思科网络技术学院理事会 Physical Layer - Standards  Standards for the Physical layer specify signal, connector, and cabling requirements.

13 思科网络技术学院理事会 Physical Layer Fundamental Principles  The three fundamental functions of the Physical layer are: － The physical components － Data encoding － Signaling

思科网络技术学院理事会 Physical Signaling and Encoding: Representing Bits

15 思科网络技术学院理事会 Signaling Bits for the Media  All communication from the human network becomes binary digits, which are transported individually across the physical media.  Bits are represented on the medium by changing one or more of the following characteristics of a signal: － Amplitude － Frequency － Phase

16 思科网络技术学院理事会 Signaling Bits for the Media  Method of signaling: － Non Return to Zero (NRZ) Signaling － Manchester Encoding － 4B/5B

17 思科网络技术学院理事会 Encoding – Grouping Bits  One way to provide frame detection is to begin each frame with a pattern of signals representing bits.

18 思科网络技术学院理事会 Encoding – Grouping Bits  A code group is a consecutive sequence of code bits that are interpreted and mapped as data bit patterns.  Advantages using code groups include: － Reducing bit level error － Limiting energy transmitted － D istinguish data from control － Better media error detection

19 思科网络技术学院理事会 Data carrying Capacity  Data transfer can be measured in three ways: － Bandwidth － Throughput － Goodput  Bandwidth Digital bandwidth measures the amount of information that can flow from one place to another in a given amount of time.

20 思科网络技术学院理事会 Data carrying Capacity  Data Throughput and Goodput

思科网络技术学院理事会 Physical Media – Connecting Communication

22 思科网络技术学院理事会 Types of Physical Media  Several media characteristics defined by Physical layer standards.

23 思科网络技术学院理事会 Types of Physical Media  Several media characteristics defined by Physical layer standards.

24 思科网络技术学院理事会 Copper Media  The types of copper cabling include: － Coaxial cable － Twisted-pair cable · Unshielded Twisted-pair · Shielded Twisted-pair

25 思科网络技术学院理事会 Copper Media  External Signal Interference

26 思科网络技术学院理事会 Unshielded Twisted Pair (UTP) Cable  The basic characteristics of UTP cable

27 思科网络技术学院理事会 Unshielded Twisted Pair (UTP) Cable  UTP Cable Types － Ethernet Straight-through － Ethernet Crossover － Rollover

28 思科网络技术学院理事会 Other Copper Cable  Coaxial cable

29 思科网络技术学院理事会 Other Copper Cable  Coaxial cable

30 思科网络技术学院理事会 Other Copper Cable  Shielded Twisted-Pair (STP) Cable

31 思科网络技术学院理事会 Copper Media Safety  Types of safety issues when working with copper cabling

32 思科网络技术学院理事会 Fiber Media  Fiber Media Cable Construction

33 思科网络技术学院理事会 Fiber Media  Fiber Media Cable Construction

34 思科网络技术学院理事会 Fiber Media  Fiber provides full duplex communications with a cable dedicated to each direction.

35 思科网络技术学院理事会 Fiber Media  Fiber optic cables can be broadly classified into two types: single-mode and multimode. i

36 思科网络技术学院理事会 Wireless Media  Wireless media carry electromagnetic signals at radio and microwave frequencies that represent the binary digits of data communications.

37 思科网络技术学院理事会 Wireless Media  Types of Wireless Networks － Standard IEEE － Standard IEEE － Standard IEEE － Global System for Mobile Communications (GSM)

38 思科网络技术学院理事会 Wireless Media  The Wireless LAN In general, a wireless LAN requires the following network devices: － Wireless Access Point (AP) － Wireless NIC adapters

39 思科网络技术学院理事会 Wireless Media  WLAN Ethernet-based standards include:  IEEE a - Operates in the 5 GHz frequency band and offers speeds of up to 54 Mbps.  IEEE b - Operates in the 2.4 GHz frequency band and offers speeds of up to 11 Mbps.  IEEE g - Operates in the 2.4 GHz frequency band and offers speeds of up to 54 Mbps.  IEEE n - The proposed standard defines frequency of 2.4 GHz or 5 GHz. The typical expected data rates are 100 Mbps to 210 Mbps with a distance range of up to 70 meters.

40 思科网络技术学院理事会 Media Connectors  Common Copper Media Connectors

41 思科网络技术学院理事会 Media Connectors  Correct Connector Termination

42 思科网络技术学院理事会 Media Connectors  Common Optical Fiber Connectors

思科网络技术学院理事会 Labs – Media Connectors

44 思科网络技术学院理事会. Category 5 UTP Cable Tests  Lab 8.4.1: Media Connectors Lab ActivityMedia Connectors Lab Activity

45 思科网络技术学院理事会. Summary

46 思科网络技术学院理事会.