© 2007 Cisco Systems, Inc. All rights reserved.Cisco Public 1 Version 4.0 OSI Physical Layer Network Fundamentals – Chapter 8

2 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public What Will we Learn from chapter 8?  Physical layer protocols and services in supporting communication across data networks  The role of signals used to represent bits as a frame transported across the local media  The purpose of Physical layer signaling and encoding used in networks  Basic characteristics of copper, fiber and wireless network media

3 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Physical Layer Protocols & Services

4 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Physical Layer Protocols & Services

5 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public OSI Model – PDU– protocol - hardware  Layer 7data  Layer 6data  Layer 5data  Layer 4segmentsTCP,UDP  Layer 3packetsIProuters  Layer 2framesMAChubs, bridges, switches  Layer 1bitsamplifiers, repeaters *PDU – Protocol Data Unit (may contain control information) Layers 1 thru 4.

6 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Physical Layer Protocols & Services

7 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Physical Layer Protocols & Services

8 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Physical Layer Protocols & Services

9 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Modulation A technique for processing signals in which two waves are combined to produce a wave that possesses characteristics of both and can be decoded to separate these characteristics.  Information wave - the wave containing the signal you want to transmit.  Carrier wave - the wave that is modulated, and whose properties are constant and known to both the sender and receiver.  Guided waves - waves that are bound to a carrier wave’s frequency.

10 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Modulation  Modulator - the device that imposes the message signal on the carrier signal at the transmission end.  Demodulator - separates the message from the carrier signal at the receiving end.  Modem - a device used to convert digital into analog signals and analog into digital signals.

11 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Modulation

12 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Amplitude Modulation

13 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Amplitude Modulation t =>

14 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Frequency Modulation A method of modulation in which the frequency of the carrier signal is modified by the addition of the message signal.  Frequency shift keying (FSK) - when FM signals are converted into digital signals, the differing frequencies are conveyed as either 0s or 1s.

15 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Frequency Modulation

16 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Frequency Modulation

17 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Phase Modulation

18 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Phase Modulation

19 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Phase Modulation

20 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Pulse Code Modulation (PCM) The process of converting analog signals into digital signals  Sampling - the first step in converting analog signals to digital signals is to measure the amplitude of an analog signal at multiple instants. The higher the sampling rate, the more closely the digital signal resembles the original analog signal.

21 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Pulse Code Modulation (PCM)

22 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Physical Layer Signaling and Encoding

23 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Physical Layer Signaling and Encoding

24 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Characteristics & Uses of Network Media

25 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public 10 base 2 and 10 base 5 are terms used to describe coaxial cables. 10 is the speed 10 mbps base- signaling(baseband) 2 or 5 denotes the max length that can be used. 200 meters or base 2 – 10base 5

26 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public 10base-T – 100base-T – 1000base-T 1xxx base T used to describe twisted pair cabling 1xxx is the speed in mbps base- signaling (baseband) The T stands for twisted pair

27 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public For Gigabit Ethernet, industry offerings include these types of wiring: 1000BASE-SX (a short laser wavelength on multimode fiber optic cable for a maximum length of 550 meters) 1000BASE-LX/LH (a long wavelength for a "long haul" fiber optic cable for a maximum length of 10 kilometers) 1000BASE-ZX (an extended wavelength single-mode optical fiber for up to 100 kilometers) 1000BASE-CX (two pairs of 150-ohm shielded twisted pair cable for a maximum length of 25 meters) 1000BASE-T (four pairs of Category 5 unshielded twisted pair cable for a maximum length of 100 meters) Fiber

28 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Characteristics & Uses of Network Media

29 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Characteristics & Uses of Network Media

30 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Characteristics & Uses of Network Media

31 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Characteristics & Uses of Network Media Shielded twisted pair (two pair) Outer Jacket Braided shield Foil shield Twisted Pairs Unshielded twisted pair (four pair) Twisted Pair Plastic insulation Outer Jacket Overall shield Twisted Pair ScTP (a hybrid UTP) shielded

32 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Characteristics & Uses of Network Media

33 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Fiber Optics

34 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Fiber Optics

35 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Coaxial cable anatomy A CD B

36 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Fiber-optic cable anatomy Buffer coating Core Cladding microns microns microns microns Single-modeMultimode

37 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Single and Multimode Fiber-optical connectors ST ConnectorSC Connector MultimodeSingle-Mode

38 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Fiber Optics – Compare Single and Multi Modes

39 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Characteristics & Uses of Network Media

40 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Characteristics & Uses of Network Media

41 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Characteristics & Uses of Network Media

42 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public What Did I Learn from chapter 8?  Physical layer protocols and services in supporting communication across data networks  The role of signals used to represent bits as a frame transported across the local media  The purpose of Physical layer signaling and encoding used in networks  Basic characteristics of copper, fiber and wireless network media

43 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public OSI Physical Layer Next Ethernet