Presentation_ID 1 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Chapter 4: Network Access

Presentation_ID 2 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential 4.1 Physical Layer Protocols

Presentation_ID 3 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Getting it Connected Connecting to the Network

Presentation_ID 4 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Getting it Connected Connecting to the Network (cont.)

Presentation_ID 5 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Getting it Connected Network Interface Cards Connecting to the Wireless LAN with a Range Extender

Presentation_ID 6 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Purpose of the Physical Layer The Physical Layer

Presentation_ID 7 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Purpose of the Physical Layer Physical Layer Media

Presentation_ID 8 © 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 9 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Fundamental Principles of Layer 1 Physical Layer Fundamental Principles 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 10 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Fundamental Principles of Layer 1 Bandwidth

Presentation_ID 11 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Fundamental Principles of Layer 1 Throughput

Presentation_ID 12 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Fundamental Principles of Layer 1 Types of Physical Media Gigabit Ethernet Interfaces SHDSL Interface Management Ports FastEthernet Switch Ports USB Mini-B Connector USB Type A Connector

Presentation_ID 13 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential 4.2 Network Media

Presentation_ID 14 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Copper Cabling Characteristics of Copper Media

Presentation_ID 15 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Copper Cabling Copper Media Shielded Twisted Pair (STP) Cable Unshielded Twisted Pair (UTP) Cable Coaxial Cable

Presentation_ID 16 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Copper Cabling UTP Cable

Presentation_ID 17 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Copper Cabling STP Cable Foil Shields Braided or Foil Shield

Presentation_ID 18 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Copper Cabling Coaxial Cable

Presentation_ID 19 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Copper Cabling Cooper Media Safety

Presentation_ID 20 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential UTP Cabling Properties of UTP Cabling UTP cable does not use shielding to counter the effects of EMI and RFI. Instead, cable designers have discovered that they can limit the negative effect of crosstalk by:  Cancellation  Varying the number of twists per wire pair

Presentation_ID 21 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential UTP Cabling UTP Cabling Standards

Presentation_ID 22 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential UTP Cabling UTP Connectors

Presentation_ID 23 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential UTP Cabling Types of UTP Cable

Presentation_ID 24 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential UTP Cabling Testing UTP Cables After installation, a UTP cable tester should be used to test for the following parameters:  Wire map  Cable length  Signal loss due to attenuation  Crosstalk

Presentation_ID 25 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Fiber Optic Cabling Properties of Fiber Optic Cabling Fiber-optic cabling is now being used in four types of industry:  Enterprise Networks  Fiber-to-the-home (FTTH) and Access Networks  Long-Haul Networks  Submarine Networks

Presentation_ID 26 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Fiber Optic Cabling Fiber Media Cable Design

Presentation_ID 27 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Fiber Optic Cabling Types of Fiber Media

Presentation_ID 28 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Fiber Optic Cabling Network Fiber Connectors

Presentation_ID 29 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Fiber Optic Cabling Testing Fiber Cables

Presentation_ID 30 © 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 31 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Wireless Media Properties of Wireless Media Wireless does have some areas of concern including:  Coverage area  Interference  Security

Presentation_ID 32 © 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 Mb/s 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 33 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Wireless Media Wireless LAN Cisco Linksys EA ac Wireless Router

Presentation_ID 34 © 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 35 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential 4.3 Data Link Layer Protocols

Presentation_ID 36 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Purpose of the Data Link Layer The Data Link Layer

Presentation_ID 37 © 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 38 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Purpose of the Data Link Layer Media Access Control The Data Link Layer

Presentation_ID 39 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Purpose of the Data Link Layer Providing Access to Media

Presentation_ID 40 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Data Link Layer Formatting Data for Transmission

Presentation_ID 41 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Layer 2 Frame Structure Creating a Frame

Presentation_ID 42 © 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 43 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Topologies Controlling Access to the Media

Presentation_ID 44 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Topologies Physical and Logical Topologies

Presentation_ID 45 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Topologies Physical and Logical Topologies (cont.)

Presentation_ID 46 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential WAN Topologies Common Physical WAN Topologies

Presentation_ID 47 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential WAN Topologies Physical Point-to-Point Topology

Presentation_ID 48 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential WAN Topologies Logical Point-to-Point Topology

Presentation_ID 49 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential WAN Topologies Half- and Full-Duplex Half-Duplex Full-Duplex

Presentation_ID 50 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential LAN Topologies Physical LAN Topologies

Presentation_ID 51 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential LAN Topologies Logical Topology for Shared Media

Presentation_ID 52 © 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 53 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential LAN Topologies Multi-Access Topology

Presentation_ID 54 © 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 wanting to transmit must wait their turn No collisions May use a token passing method Token Ring (IEEE 802.5) FDDI

Presentation_ID 55 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential LAN Topologies Ring Topology

Presentation_ID 56 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Data Link Frame The Frame

Presentation_ID 57 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Data Link Frame The Header

Presentation_ID 58 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Data Link Frame Layer 2 Address

Presentation_ID 59 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Data Link Frame The Trailer

Presentation_ID 60 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Data Link Frame LAN and WAN Frames

Presentation_ID 61 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Data Link Frame Ethernet Frame

Presentation_ID 62 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Data Link Frame Point-to-Point Protocol Frame

Presentation_ID 63 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Data Link Frame Wireless Frame

Presentation_ID 64 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Data Link Frame Wireless Frame Protocol Version field: Version of frame in use Type and Subtype fields: Identifies one of three functions and sub functions of the frame: control, data, and management To DS field: Set to 1 in data frames destined for the distribution system (devices in the wireless structure) From DS field: Set to 1 in data frames exiting the distribution system More Fragments field: Set to 1 for frames that have another fragment Retry field: Set to 1 if the frame is a retransmission of an earlier frame Power Management field: Set to 1 to indicate that a node will be in power-save mode More Data field: Set to 1 to indicate to a node in power-save mode that more frames are buffered for that node Wired Equivalent Privacy (WEP) field: Set to 1 if the frame contains WEP encrypted information for security Order field: Set to 1 in a data type frame that uses Strictly Ordered service class (does not need reordering) Duration/ID field: Depending on the type of frame, represents either the time, in microseconds, required to transmit the frame or an association identity (AID) for the station that transmitted the frame Destination Address (DA) field: MAC address of the final destination node in the network Source Address (SA) field: MAC address of the node that initiated the frame Receiver Address (RA) field: MAC address that identifies the wireless device that is the immediate recipient of the frame Fragment Number field: Indicates the number for each fragment of a frame Sequence Number field: Indicates the sequence number assigned to the frame; retransmitted frames are identified by duplicate sequence numbers Transmitter Address (TA) field: MAC address that identifies the wireless device that transmitted the frame Frame Body field: Contains the information being transported; for data frames, typically an IP packet FCS field: Contains a 32-bit cyclic redundancy check (CRC) of the frame