© 2008 Cisco Systems, Inc. All rights reserved.Cisco ConfidentialPresentation_ID 1 Chapter 9: Network Access Network Basics

Presentation_ID 2 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Chapter 9: Objectives Students will be able to:  Explain the role of the data link layer in supporting communications across data networks.  Compare media access control techniques and logical topologies used in networks.  Explain how physical layer protocols and services support communications across data networks.  Build a simple network using the appropriate.

Presentation_ID 3 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Chapter Data Link Layer 9.2 Media Access Control 9.3 Physical Layer 9.4 Network Media 9.5 Summary

Presentation_ID 4 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Purpose of the Data Link Layer The Data Link Layer

Presentation_ID 5 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Purpose of the Data Link Layer Data Link Sublayers Network Data Link LLC Sublayer MAC Sublayer Physical Ethernet Ethernet Wi-Fi Wi-Fi Bluetooth Bluetooth

Presentation_ID 6 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Purpose of the Data Link Layer Media Access Control

Presentation_ID 7 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Purpose of the Data Link Layer Providing Access to Media

Presentation_ID 8 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Data Link Layer Layer 2 Frame Structure

Presentation_ID 9 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Layer 2 Frame Structure Creating a Frame

Presentation_ID 10 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Data Link Layer Layer 2 Standards

Presentation_ID 11 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Layer 2 Standards Data Link Layer Standards Standard organization Networking Standards IEEE 802.2: Logical Link Control (LLC) 802.3: Ethernet 802.4: Token bus 802.5: Token passing : Wireless LAN (WLAN) & Mesh (Wi-Fi certification) : Bluetooth : WiMax ITU-T G.992: ADSL G G.8199: MPLS over Transport aspects Q.921: ISDN Q.922: Frame Relay ISO HDLC (High Level Data Link Control) ISO 9314: FDDI Media Access Control (MAC) ANSI X3T9.5 and X3T12: Fiber Distributed Data Interface (FDDI)

Presentation_ID 12 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Topologies Controlling Access to the Media

Presentation_ID 13 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Topologies Physical and Logical Topologies

Presentation_ID 14 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential WAN Topologies Common Physical WAN Topologies

Presentation_ID 15 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential WAN Topologies Point-to-Point Topology

Presentation_ID 16 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential WAN Topologies Logical Point-to-Point Topology

Presentation_ID 17 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential WAN Topologies Half and Full Duplex

Presentation_ID 18 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential LAN Topologies Physical LAN Topologies

Presentation_ID 19 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential LAN Topologies Logical Topology for Shared Media

Presentation_ID 20 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential LAN Topologies Contention-Based Access CharacteristicsContention-Based Technologies Stations can transmit at any time Collision exist There are mechanisms to resolve contention for the media CSMA/CD for Ethernet networks CSMA/CA for wireless networks

Presentation_ID 21 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential LAN Topologies Multi-Access Topology

Presentation_ID 22 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential LAN Topologies Controlled Access CharacteristicsControlled Access Technologies Only one station can transmit at a time Devices wishing to transmit must wait their turn No collisions May use a token passing method Token Ring (IEEE 802.5) Fiber Distributed Data Interface (FDDI)

Presentation_ID 23 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential LAN Topologies Ring Topology

Presentation_ID 24 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Data Link Frame The Frame

Presentation_ID 25 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Data Link Frame The Header

Presentation_ID 26 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Data Link Frame Layer 2 Address

Presentation_ID 27 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Data Link Frame The Trailer

Presentation_ID 28 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Data Link Frame LAN and WAN Frames

Presentation_ID 29 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Data Link Frame Ethernet Frame

Presentation_ID 30 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Data Link Frame Point-to-Point Protocol Frame

Presentation_ID 31 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Data Link Frame Wireless Frame

Presentation_ID 32 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Network Access Physical Layer

Presentation_ID 33 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Purpose of the Physical Layer The Physical Layer

Presentation_ID 34 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Purpose of the Physical Layer Physical Layer Media

Presentation_ID 35 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Purpose of the Physical Layer Physical Layer Standards Standard organization Networking Standards ISO ISO 8877: Officially adopted the RJ connectors (e.g., RJ-11, RJ-45) ISO 11801: Network cabling standard similar to EIA/TIA 568. EIA/TIA TIA-568-C: Telecommunications cabling standards, used by nearly all voice, video and data networks. TIA-569-B: Commercial Building Standards for Telecommunications Pathways and Spaces TIA-598-C: Fiber optic color coding TIA-942: Telecommunications Infrastructure Standard for Data Centers ANSI 568-C: RJ-45 pinouts. Co-developed with EIA/TIA ITU-T G.992: ADSL IEEE 802.3: Ethernet : Wireless LAN (WLAN) & Mesh (Wi-Fi certification) : Bluetooth

Presentation_ID 36 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Characteristics of the Physical Layer Physical Layer Functions Media Physical Components Frame Encoding Technique Signalling Method Copper cable UTP Coaxial Connectors NICs Ports Interfaces Manchester Encoding Non-Return to Zero (NRZ) techniques 4B/5B codes are used with Multi-Level Transition Level 3 (MLT-3) signaling 8B/10B PAM5 Changes in the electromagnetic field Intensity of the electromagnetic field Phase of the electromagnetic wave Fiber Optic cable Single-mode Fiber Multimode Fiber Connectors NICs Interfaces Lasers and LEDs Photoreceptors Pulses of light Wavelength multiplexing using different colors A pulse equals 1. No pulse is 0. Wireless media Access Points NICs Radio Antennae DSSS (direct-sequence spread- spectrum) OFDM (orthogonal frequency division multiplexing) Radio waves

Presentation_ID 37 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Characteristics of the Physical Layer Physical Components Gigabit Ethernet Interfaces SHDSL Interface Management Ports USB Type A Connector FastEthernet Switch ports USB Mini-B Connector

Presentation_ID 38 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Characteristics of the Physical Layer Frame Encoding Techniques  Manchester encoding  Non-Return to Zero (NRZ)

Presentation_ID 39 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Characteristics of the Physical Layer Signaling Method Asynchronous Signal Synchronous Signal Arbitrary gap of time Bursty data Data transitions align with bit time slots Bit time slot

Presentation_ID 40 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Characteristics of the Physical Layer Signaling Method Amplitude modulation Frequency modulation Phase modulation

Presentation_ID 41 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Characteristics of the Physical Layer Signaling Method

Presentation_ID 42 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Characteristics of the Physical Layer Bandwidth

Presentation_ID 43 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Characteristics of the Physical Layer Throughput

Presentation_ID 44 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Network Media Copper Cabling

Presentation_ID 45 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Copper Cabling Characteristics of Copper Media

Presentation_ID 46 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Copper Cabling Copper Media Shielded Twisted Pair (STP) cableUnshielded Twisted Pair (UTP) cable Coaxial cable

Presentation_ID 47 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Copper Cabling Unshielded Twisted-Pair (UTP) Cable

Presentation_ID 48 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Copper Cabling Shielded Twisted-Pair (STP) Cable Foil Shields Braided or Foil Shield

Presentation_ID 49 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Copper Cabling Coaxial Cable

Presentation_ID 50 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Copper Cabling Cooper Media Safety

Presentation_ID 51 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential UTP Cabling Properties of UTP Cabling

Presentation_ID 52 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential UTP Cabling UTP Cabling Standards

Presentation_ID 53 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential UTP Cabling UTP Connectors

Presentation_ID 54 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential UTP Cabling Types of UTP Cable

Presentation_ID 55 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential UTP Cabling LAN Cabling Areas

Presentation_ID 56 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential UTP Cabling Testing UTP Cables

Presentation_ID 57 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Fiber Optic Cabling Properties of Fiber Optic Cabling

Presentation_ID 58 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Fiber Optic Cabling Fiber Media Cable Design

Presentation_ID 59 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Fiber Optic Cabling Types of Fiber Media

Presentation_ID 60 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Fiber Optic Cabling Network Fiber Connectors

Presentation_ID 61 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Fiber Optic Cabling Testing Fiber Cables

Presentation_ID 62 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Fiber Optic Cabling Fiber versus Copper Implementation issuesCopper mediaFibre-optic Bandwidth supported 10 Mbps – 10 Gbps10 Mbps – 100 Gbps Distance Relatively short (1 – 100 meters) Relatively High (1 – 100,000 meters) Immunity to EMI and RFI Low High (Completely immune) Immunity to electrical hazards Low High (Completely immune) Media and connector costs LowestHighest Installation skills required LowestHighest Safety precautions LowestHighest

Presentation_ID 63 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Network Media Wireless Media

Presentation_ID 64 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Wireless Media Properties of Wireless Media

Presentation_ID 65 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential IEEE standards Commonly referred to as Wi-Fi. Uses CSMA/CA Variations include: a: 54 Mbps, 5 GHz b: 11 Mbps, 2.4 GHz g: 54 Mbps, 2.4 GHz n: 600 Mbps, 2.4 and 5 GHz ac: 1 Gbps, 5 GHz ad: 7 Gbps, 2.4 GHz, 5 GHz, and 60 GHz IEEE standard Supports speeds up to 3 Mbps Provides device pairing over distances from 1 to 100 meters. IEEE standard Provides speeds up to 1 Gbps Uses a point-to-multipoint topology to provide wireless broadband access. Wireless Media Types of Wireless Media

Presentation_ID 66 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Wireless Media Wireless LAN Cisco Linksys EA ac wireless router

Presentation_ID 67 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Wireless Media Wi-Fi Standards Standard Maximum Speed Frequency Backwards compatible a 54 Mbps5 GHzNo b 11 Mbps2.4 GHzNo g 54 Mbps2.4 GHz802.11b n 600 Mbps2.4 GHz or 5 GHz802.11b/g ac 1.3 Gbps (1300 Mbps) 2.4 GHz and 5.5 GHz b/g/n ad 7 Gbps (7000 Mbps) 2.4 GHz, 5 GHz and 60 GHz b/g/n/ac

Presentation_ID 68 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Network Access Summary In this chapter, you learned:  The TCP/IP network access layer is the equivalent of the OSI data link layer (Layer 2) and the physical layer (Layer 1).  The data link layer is responsible for the exchange of frames between nodes over a physical network media.  Among the different implementations of the data link layer protocols, there are different methods of controlling access to the media.  The actual media access control method used depends on the topology and media sharing.  LAN and WAN topologies can be physical or logical.

Presentation_ID 69 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Network Access Summary In this chapter, you learned:  It is the logical topology that influences the type of network framing and media access control used.  WANs are commonly interconnected using the point-to-point, hub and spoke, or mesh physical topologies.  In shared media LANs, end devices can be interconnected using the star, bus, ring, or extended star (hybrid) physical topologies.  All data link layer protocols encapsulate the Layer 3 PDU within the data field of the frame.

Presentation_ID 70 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Network Access Summary In this chapter, you learned:  The OSI physical layer provides the means to transport the bits that make up a data link layer frame across the network media.  Hardware components such as network adapters (NICs), interfaces and connectors, cable materials, and cable designs are all specified in standards associated with the physical layer.  The physical layer standards address three functional areas: physical components, frame encoding technique, and signaling method.

Presentation_ID 71 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Network Access Summary In this chapter, you learned:  Using the proper media is an important part of network communications.  Wired communication consists of copper media and fiber cable.  There are three main types of copper media used in networking: unshielded-twisted pair (UTP), shielded-twisted pair (STP), and coaxial cable. UTP cabling is the most common copper networking media.  Optical fiber cable has become very popular for interconnecting infrastructure network devices.

Presentation_ID 72 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Network Access Summary In this chapter, you learned:  Wireless media carry electromagnetic signals that represent the binary digits of data communications using radio or microwave frequencies.  The number of wireless enabled devices continues to increase.  Wireless has become the medium of choice for home networks and is quickly gaining in popularity in enterprise networks.

Presentation_ID 73 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential