Modern Ethernet standards include 100-megabit Ethernet, Gigabit Ethernet, and 10-Gigabit Ethernet. 100-megabit Ethernet standards include 100BaseT and 100BaseFX. Gigabit Ethernet standards include 1000BaseT, 1000BaseCX, 1000BaseSX and 1000BaseLX. 10-Gigabit Ethernet standards include 10GBaseSR, 10GBaseLR and 10GBaseER which use different fiber types and wavelengths, and 10GBaseT which uses copper cabling. Higher speeds require fiber optic cabling and support longer transmission distances.

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
Standard Fiber Type Wavelength Physical Maximum
Layer Signal
Signaling Length
10GBaseSR Multimode 850 nm LAN 26-300 m
10GBaseSW Multimode 850 nm SONET/WAN 26-300 m
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
Standard Fiber Type Wavelength Physical Maximum
Layer Signal
Signaling Length
10GBaseLR Single-mode 1310 nm LAN 10 km
10GBaseLW Single-mode 1310 nm SONET/WAN 10 km
Fiber-based 10GBaseLy Summary

42. • 10GBaseEy uses an extra-long-wave-
length (1550 nm) signal over single-
mode fiber
Standard Fiber Type Wavelength Physical Maximum
Layer Signal
Signaling Length
10GBaseER Single-mode 1550nm LAN 40 km
10GBaseEW Single-mode 1550 nm SONET/WAN 40 km
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

51. • Know Your Ethernets!
– Know details of the Ethernet versions
– Use summaries and tables
– So far in the text, only the functions of a
basic switch have been explained
– More to see in terms of capabilities of
switches