Unit 5: Chapter 5, Ethernet LANs NT1210 Introduction to Networking Unit 5: Chapter 5, Ethernet LANs 1

Class Agenda 4/12/16 Learning Objectives Lesson Presentation and Discussions. Midterm Exams is in the next class. Lab Activities will be performed in class. Assignments will be given in class. Break Times. 10 Minutes break in every 1 Hour. Note: Submit all Assignment and labs due today.

Objectives Define Ethernet LAN concepts. Evaluate the advantages and disadvantages of Ethernet technology in LANs. Analyze the advantages of using Layer 2 devices to segment LANs. Troubleshoot wired LANs for connectivity and performance. 3

Defining Ethernet LANs Ethernet: Originally developed as LAN technology Connect end-user devices in one site with devices relatively close by Each LAN site connects to WAN via router Ethernet standards kept growing to support faster speeds and longer cabling distances Modern Ethernet networks might be LANs or WANs Companies generally own their own LANs 4

Principles of Ethernet Ethernet was first developed by Xerox Corporation. The original intent was to create a technology to allow computers to connect with laser printers. From this humble beginnings, Ethernet rose to be used to interconnect such devices as computers, printers, wireless access points, servers, switches, routers, video-game systems, and more.

Defining Ethernet LANs Late 1970s: End of proprietary standards LAN standards all start with IEE Standard 802 6 Table 5-1

Characteristics defined by the IEEE 802 standards committee Bandwidth Access CSMA/CD technology Channel Bonding Topology Options Media Types Analogy: Imagine that you are driving around in Europe in an American made car, and suddenly you hear a really bad sound from one of the wheels. You stop at the next service station to have it checked out and are told that your brakes are worn out and need to be replaced. You can see that the service station has a lot of brake inventory so you think this is not going to take long to fix. Sadly, the owner tells you that he cannot help you because he only has metric based brake pads and they will not fit on American cars. Had you known this could happen, you might have brought some spare parts with you. Such is the need to understand the importance of standards. The reason for the existence of the IEEE is to create and ratify standards for products that consume or transmit electrical power. They do not deal with the quality of the finish product like Underwriter’s Labs do, but rather they focus on the standards used to create safe and effective usage of electricity and related technologies including signaling standards. In the world of networking these standards all begin with the number 802 and are followed by a dot and some number and letter combination. While the Net+ exam requires you to know these for answering questions, fortunately, the real world only needs you to really know a few. They are: 802.1 (especially as it relates to switching technologies) 802.3 Ethernet CSMA/CD 802.11 Wireless On a lesser level, you will want to be familiar with these: 802.5 Token Ring CSMA/CA (decreasing in importance) 802.9 Integrated Voice and Data (increasing in importance) 802.10 Network Security (increasing in importance)

Other Standards 802.1 (especially as it relates to switching technologies) 802.3 Ethernet CSMA/CD 802.11 Wireless On a lesser level, you will want to be familiar with these: 802.5 Token Ring CSMA/CA (decreasing in importance) 802.9 Integrated Voice and Data (increasing in importance) 802.10 Network Security (increasing in importance)

Defining Ethernet LANs Three Important IEEE LAN Standards Working Group Common Reference Purpose 802.2 Logical Link Control Defines features in common across Ethernet, Token Ring, and others 802.3 Ethernet Defines features specific to Ethernet 802.5 Token Ring Defines features specific to Token Ring Key Original IEEE 802 LAN Standards 9 Table 5-1

Defining Ethernet LANs: LAN vs. WAN Many Telcos today offer WAN services to customer site uses an Ethernet standard. The LANs at each site can still use Ethernet, but the WAN links also use Ethernet. Ethernet LAN vs. Ethernet WAN 10 Figure 5-1

Defining Ethernet LANs: Wired vs. Wireless Wired: 802.3 Ethernet Wireless: 802.11 Wireless LANs Comparing the Combined Hybrid LAN to a Wireless-Only LAN Edge 11 Figure 5-3

Ethernet Origins IEEE 802.3, in general this in is interchangeable with the term Ethernet. In the early days, it was called 10BASE5. 10 = 10 Mbps (10 million bits per second) BASE = Baseband, one signal on the line at a time. 5 = 500 meters of cable max The cable use was RG-6, became known as thicknet and is a coaxial cable.

Defining Ethernet LANs: Ethernet Bit Rates 10BASE-5: Standard that used thick coaxial cabling (thicknet) with bus topology 10BASE-2: Standard that used thinner coaxial cable (Thinnet) with bus topology 10BASE-T: Ethernet standard deployed in 1990 used UTP cabling with star topology Ethernet Standards Dates, Speeds, and Common Names 13 Figure 5-5

Defining Ethernet LANs: Standard Names Original IEEE IEEE Shorthand Name Informal Name(s) Speed Typical Cabling 802.3i 10BASE-T Ethernet 10 Mbps UTP 802.3u 100BASE-T Fast Ethernet (Fast E) 100 Mbps 802.3z 1000BASE-X Gigabit Ethernet (Gig E, GbE) 1000 Mbps Fiber 802.3ab 1000BASE-T 802.3ae 10GBASE-X 10 GbE 10 Gbps 802.3an 10GBASE-T 802.3ba 40GBASE-X 40GbE (40 GigE) 40 Gbps 100GBASE-X 100GbE (100 GigE) 100 Gbps Ethernet Naming Summary 14 Table 5-4

LANs: Topologies Modern Ethernet LANs use a star topology (physical topologies refers to the shape of the network). In a simple Ethernet LAN, all the devices connect to a single LAN switch. If you spread the devices out to all points on the compass, it looks a little like a star. Star Topology in an Ethernet LAN Compared to a Drawing of a Sun (Star) 15 Figure 5-7

Duplex Auto-Negotiation Duplex setting on link determines whether to use half- duplex or full-duplex Devices can negotiate duplex setting with auto- negotiation Modern LANs use full duplex, but if older hubs exist on network, links have to auto-negotiate History of Half and Full Duplex 16

Building Ethernet LANs: Distance Considerations UTP links: Maximum 100 meters Multimode links: Several hundred meters (3-6) Single mode links: Several kilometers (30-60) 17

Building Ethernet LANs: UTP Pinouts Straight-through Cables: Used to connect 2 devices (e.g., PCs and switches) Use wire pairs 1, 2 and 3, 6 100BASE-T Transmit and Receive Logic, PC to Switch, with Straight-through Cable 18 Figure 5-15

Building Ethernet LANs: UTP Pinouts Crossover Cables: How the wire pairs communicate Crossover Cable for 10BASE-T and 100BASE-T 19 Figure 5-16

Building Ethernet LANs: UTP Pinouts Crossover Cables: TIA cabling standards specify which color pair to put in each position in connectors on each end of cable T568A on one end, and T568B on the other. TIA Pinout Standards T568A and T568B to Create a Crossover Cable 20 Figure 5-17

Exploring Ethernet: MAC Address IEEE defines MAC addresses as 48-bit numbers usually written in hexadecimal (hex) Each hex digit represents 4 bits (MAC address = 12 hex digits) Examples of how MAC address expressed 00000010 00010010 00110100 01010110 01111000 10011010 02123456789A 0212.3456.789A 02.12.34.56.78.9A 21

Exploring Ethernet: MAC Address Universal MAC address: Permanent address unique across all networks Uses 2-part format: Organizationally Unique Identifier (OUI): Code registered to vendor; first half of MAC address Vendor assigned: Unique serial number chosen by vendor; second half of MAC address IEEE Organizationally Unique Identifier (OUI) and Unique MAC Addresses 22 Figure 5-20

Exploring Ethernet: MAC Address IEEE Organizationally Unique Identifier (OUI) and Unique MAC Addresses 23 Figure 5-20

Exploring Ethernet: LAN Switching Example of how a switch forwards frames Example of how a switch forwards frames using 4 PCs: A, B, C, and D PC A sends a frame destined for PC D (MAC address 0000.DDDD.DDDD) Switch's port identifiers with the switch's MAC address table find the location of PC D on the network through its MAC address Explanation of Graphic: PC A's NIC builds a frame with the destination address of 0000.DDDD.DDDD and sends the frame SW1 receives the frame, compares the destination MAC address to the MAC table where it finds an entry that lists G4 as the port for that MAC address’ device. MAC table entry on SW1 SW1 forwards the unchanged Ethernet frame out its G4 port to PC D (destination) Switch Forwarding Decision: Single Switch 24 Figure 5-21

ARP The Address Resolution Protocol (ARP) is used to resolve a logical (IP) address to a physical (MAC) address. This protocol is used often when new routes are needed or a new IP address is encountered by your network device where traffic needs to be routed.

Exploring Ethernet: Switch Learning Switches build MAC address tables two ways Entries manually typed into MAC address table Switch learns MAC addresses by reading frames that pass through it SW1 Learns the MAC Address of PC A 26

LAN Troubleshooting Ping and Traceroute Arp ping Netstat, nbtstat Ipconfig, ifconfig, Nslookup

Unit 5 Assignment Unit 5 Assignment 1: Exploring LAN Switches Unit 5 Assignment 2: Ethernet Local Area Networks Review Unit 5 Research Project 1: Chapter 6 Mind Maps (Instructor example)

Unit 5 Lab Unit 5 Lab 5.1: LAN Standards Unit 5 Lab 5.2: MAC and IP Addresses Unit 5 Lab 5.3: Finding Network Settings Unit 5 Lab 5.4: Basic Network Troubleshooting

Reading Assignment Odom, Chapter 5: Ethernet LANs Richardson, Lab Manual Chapter 5 Midterm Exams will be held in the next class