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Modern Ethernet

Modern Ethernet. Chapter 5. Objectives. Describe the varieties of 100-megabit Ethernet Discuss copper- and fiber-based Gigabit Ethernet Compare the competing varieties of 10-Gigabit Ethernet. Overview. Three Parts to Chapter 5. 100-megabit Ethernet standards Gigabit Ethernet standards

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Modern Ethernet

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  1. Modern Ethernet Chapter 5

  2. Objectives • Describe the varieties of 100-megabit Ethernet • Discuss copper- and fiber-based Gigabit Ethernet • Compare the competing varieties of 10-Gigabit Ethernet

  3. Overview

  4. Three Parts to Chapter 5 • 100-megabit Ethernet standards • Gigabit Ethernet standards • 10-Gigabit Ethernet standards

  5. Ethernet Facts • There are only four Ethernet speeds: 10 mega-bit, 100 megabit, 1 gigabit, and 10 gigabit • Every version of Ethernet uses either unshield-ed twisted pair (UTP) or fiber-optic. (With a few, rare exceptions) • Every version of Ethernet uses a hub or switch, although hubs are incredibly rare today.

  6. Ethernet Facts (continued) • Only 10- and 100-megabit Ethernet may use a hub. Gigabit and 10-Gigabit Ethernet networks must use a switch. • Every version of Ethernet has a limit of 1024 nodes. • Every UTP version of Ethernet has a maximum distance from the switch or hub to the node of 100 meters.

  7. 100-Megabit Ethernet

  8. 100BaseT • 100BaseT4 • CAT 3 or better cabling • Uses all four pair of wires • Disappeared from the market after 100BaseTX generally accepted • 100BaseTX • Dominant 100-megabit standard by the late 1990s • The term “100BaseT” now applies to this standard

  9. 100BaseTX Summary • Speed: 100 Mbps • Signal type: Baseband • Distance: 100 meters between the hub and the node • Node limit: No more than 1,024 nodes per hub • Topology: Star bus topology: physical star, logical bus • Cable type: Uses CAT5(e) or better UTP cabling with RJ-45 connectors

  10. Upgrading 10BaseT network to 100BaseT • CAT 5 cable or better • Replace all old 10BaseT NICs with 100BaseT NICs • Replace 10BaseT hubs or switches with 100BaseT hubs or switches • Multispeed, auto-sending NICs and hubs/switches ease the upgrade

  11. Multispeed, autosensing NIC • When first connected, it negotiates automatically with the hub or switch • If both do 100BaseT, they will use that mode • If the hub/switch only does 10BaseT, NIC does 10BaseT

  12. Figure 5.1 Typical 100BaseT NIC

  13. Figure 5.2 Auto-negotiation in action

  14. Distinguishing 10BaseT NIC from 100BaseT NIC • Inspect closely • Look for something indicating the card’s speed • All modern NICs are multispeed and auto-sensing

  15. Figure 5.3 Typical 100BaseT NIC in Vista

  16. 100BaseFX • UTP versus fiber-optic • UTP cannot meet the needs of every organization • 100-meter distance limit inadequate for large buildings and campuses • Lack of electrical shielding • Easy to tap • Fast Ethernet refers to all the 100-Mbps Ethernet standards

  17. 100BaseFX Summary • Speed: 100 Mbps • Signal type: Baseband • Distance: Two kilometers between hub and node • Node limit: No more than 1,024 nodes per hub • Topology: Star bus topology: physical star, logical bus • Cable type: Uses multimode fiber cabling with ST or SC connectors

  18. Full-Duplex Ethernet • Early 100BaseT NICs were half-duplex • Could both send and receive data • But not at the same time • IEEE added full-duplex to the standard • Device sends and receives at the same time • By late 1990s, most 100BaseT cards could auto-negotiate for full-duplex • NIC and hub/switch determine full-or-half duplex • Setting can be forced through the operating system

  19. Figure 5.4 Half-duplex; sending at the top, receiving at the bottom

  20. Figure 5.5 Full-duplex

  21. Figure 5.6 Forcing speed and duplex in Windows Vista

  22. Gigabit Ethernet

  23. IEEE 802.3ab called 1000BaseT • Most dominant Gigabit Ethernet • Four-pair UTP • Maximum cable length 100 meters • Connectors and ports look exactly like 10BaseT, 100BaseT

  24. IEEE 802.3z known as 1000BaseX • 1000BaseCX • Twinaxial cable • Shielded 150-Ohm • Maximum length of 25 meters • This standard made little progress

  25. Figure 5.7 Twinaxial cable

  26. IEEE 802.3z (continued) • 1000BaseSX • More common • Multimode fiber-optic cable • Maximum cable length 200 to 500 meters, depending on manufacturer • Uses 850-nm wavelength LED • Devices look exactly like 100BaseFX products • SC is the most common type of connection

  27. IEEE 802.3z (continued) • 1000BaseLX • Long distance carrier • Single-mode (laser) cables • Maximum cable length 5 kilometers • Special repeaters increase distance to 70 kilometers! • Positioned as the Ethernet backbone of the future • Connectors look like 100BaseSX connectors

  28. New Fiber Connectors • Problems with ST and SC connectors • ST connectors are large, twist-on • Installer must twist cable—danger of fracturing fibers • Techs have trouble getting fingers around closely packed connectors • SC connectors snap in and out, but are also large • Manufacturers wanted smaller connectors for more ports

  29. New Fiber Connectors (continued) • Solution: Small Form Factor (SFF) connectors • Mechanical Transfer Registered Jack (MT-RJ) • Local Connector (LC) • Very popular • Considered the predominant fiber connector • Other fiber connectors exist • Only standards are ST and SC • Manufacturers have different connectors

  30. Figure 5.8 MT-RJ connector

  31. Figure 5.9 LC-type connector

  32. Table 5.1 Gigabit Ethernet Summary Standard Cabling Cable Details Connectors Length 1000BaseCX Copper Twinax Twinax 25 m 1000BaseSX Multimode 850 nm Variable – 220 – 500 m fiber SC is common 1000BaseLX Single- 1,300 nm Variable – 5 km mode fiber LC, SC are common 1000BaseT CAT 5e/6 Four-pair / RJ-45 100 m UTP full-duplex

  33. 10-Gigabit Ethernet

  34. Introduction to 10-Gigabit Ethernet (10-GbE) • Showing up in high-level LANs • Expected to trickle down to the desktops in near future • New technology • Large number of fiber standards • Two copper standards • 10-GbE copper product available only since 2008

  35. Fiber-base 10-GbE • IEEE challenge • Maintain the integrity of Ethernet frame • How to transfer frames at high speeds • Could use traditional Ethernet Physical layer mechanisms • Already a usable ~10 GbE fiber network (SONET) used for WANs

  36. Fiber-base 10 GbE (continued) • IEEE Actions • A set of 10GbE standards using traditional LAN Physical-layer mechanisms • A set of 10 GbE standards using SONET infrastructure over WAN fiber • Recognized need for different networking situations

  37. IEEE created several standards defined by • The type of fiber used • The wavelength of the laser or lasers • The Physical layer signaling type • Maximum signal distance (defined by previous factors)

  38. Naming convention begins with 10GBasexy • x = type of fiber (usually) and the signal wavelength • y = Physical layer signaling standard • R for LAN-based signaling • W for SONET/WAN-based signaling

  39. 10GBaseSy uses a short-wavelength (850 nm) signal over multimode Fiber-based 10GBaseSy Summary

  40. Figure 5.10 A 10GBaseSR NIC (photo courtesy of Intel Corporation)

  41. 10GBaseLy uses a long-wavelength (1310 nm) signal over single-mode Fiber-based 10GBaseLy Summary

  42. 10GBaseEy uses an extra-long-wave-length (1550 nm) signal over single-mode fiber Fiber-based 10GBaseEy Summary

  43. 10 GbE connectors • Standards do not define the type of connector • Manufacturers determine connectors

  44. Copper-based 10GbE (10GBaseT) • 2006: IEEE standard for 10GbE running on UTP • Looks and works like slower versions of UTP Ethernet • Downside: 10GBaseT running on CAT 6 has maximum cable length of only 55 meters • 10GBaseT running on CAT 6a can to go to 100 meters

  45. Table 5.2 10-GbE Summary Wavelength / Standard Cabling Cable Details Connectors Length 10GBaseSR Multimode 850 nm Not defined 26 – 300 m /SW fiber 10GBaseLR Single- 1310 nm Variable – LC 10 km /LW mode fiber is common 10GBaseER Single- 1550 nm Variable – LC, 40 km mode fiber SC are common 10GBaseT CAT 6/6a Four-pair / RJ-45 55 – 100 m UTP full-duplex

  46. 10-GbE Physical Connections • Hodgepodge of 10-GbE types • Problem: single router may need to support several connector types • Solution: multisource agreement (MSA) • Modular transceiver plugs into10-GbE equipment • Converts between media types • Many competing media types recently • 10-GbE equipment exclusive domain of high-bandwidth LANs and WANs, including the Internet

  47. Figure 5.11 XENPAK MSA

  48. Backbones • Multispeed network works best for many situations • Series of high-speed switches create a backbone • No computers (except maybe servers) on the backbone • Each floor has its own switch connecting to every node on floor • Each floor switch has a separate high-speed connection to a main switch

  49. Figure 5.12 Typical network configuration showing backbone

  50. Figure 5.13 Switches with dedicated, high-speed add-on ports

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