Gigabit Ethernet

1
Gigabit Ethernet

2

Networking the World TM

• Over 300,000 members in over 150 countries
• Members are individuals, not companies
• Develops voluntary, consensus-based industry
  standards
• Projects span subjects ranging from power
  distribution to programming languages
• IEEE 802 LAN/MAN Standards Committee is the
  authority on networking standards

3
Standards project objectives

• 1. Speed of 1000 Mb/s
• 2. Use 802.3/Ethernet frame format
• 3. Meet 802 Functional Requirements
• 4. Simple forwarding between 1000, 100, 10 Mb/s
• 5. Preserve min and max FrameSize of current
  802.3 Std
• 6. Full and Half Duplex operation
• 7. Support star-wired topologies
• 8. Maximum of 1 CSMA/CD repeater per collision
  domain
• 9. Support fiber media and if possible copper
  media
• 10. Use ANSI Fibre Channel as basis for physical
  layer
• 11. A family of Physical Layers supporting
• 11a. At least 25 m on copper
• 11b. At least 500 m on multimode fiber
• 11c. At least 3 km on single mode fiber
• 12. Maximum collision domain diameter of 200m
• 13. Support media selected from ISO/IEC 11801
• 14. Adopt flow control based on 802.3x
• 15. Specify an optional Media Independent
  Interface

4
Standards timeline
Close Sponsor Ballot
95
97
96
98
Standard!
Gigabit Task Force formed
Basic Concept Agreement
Close Working Group Ballot
5
Gigabit Ethernet Standard Current Status

• IEEE 802.3 Working Group ballot unanimously
  approved
• IEEE 802 LMSC Sponsor ballot unanimously
  approved
• IEEE Standards Boardunanimously approved
• In short - Its a standard!

6
Layer Diagram
Media Access Control (MAC) Full Duplex and/or
Half Duplex
Gigabit Media Independent Interface (GMII)
(Optional)
802.3z
802.3ab
1000BASE-T PCS
1000BASE-X PHY 8B/10B-AutoNegotiation
1000BASE-CX Copper Xcvr
1000BASE-SX Fiber Optic Xcvr
1000BASE-LX Fiber Optic Xcvr
1000BASE-T PMA
Multimode Fiber
Single-Mode or Multimode Fiber
Unshielded Twisted Pair
Shielded Copper Cable
7
Layer Mangement
1000BASE-X
Managed entities
802.3 MAC
MAC
Full/Half Duplex
GMII
AutoNegotiation
PHY
1000BASE-X PHY
MAU
PMD
8
Gigabit vs Fast Ethernet
100BASE-X
1000BASE-X
802.3 MAC
802.3 MAC
Full/Half Duplex
Full/Half Duplex
MII
4 bit
GMII
8 bit
100BASE-X PHY
4B/5B Code
1000BASE-X PHY
8B/10B Code
125 MBaud
1250 MBaud
PMD
PMD
Point to point
Point to point
duplex link media
duplex link media
(fiber, twisted pair)
(fiber, shielded twisted pair)
9
Media Access Control (MAC)

• 802.3z adds two new features to the MAC
• Carrier Extension
• Frame bursting
• Applicable only to half-duplex operation
• 802.3z extends full duplex (802.3x) operation to
  1000 Mb/s
• Gigabit Ethernet networks will be predominately
  full duplex

10
Gigabit Media Independent Interface (GMII)

• Provides convenient division of functions
• High speed, mixed signal circuits in PHY chip
• Complex, high density circuits in MAC chip
• Supports multi-vendor interoperabiltiy at the
  chip level
• Allows for innovation and development of new
  physical layers
• Trivially simple to implement
• Shares pins with the 10 bit interface

11
1000BASE-X PHY

• 8B/10B encode and decode
• 8 bit bytes are encoded as a 10 bit symbols
• Run-length limited (no long sequences of 1 or 0)
• Serial/Parallel conversion
• Clock recovery
• Low level framing and error checking

12
1000BASE-X PHY
GMII
8 control
8 control
GMII 125 million bytes/s
H G F E D C B A
H G F E D C B A
PCS
a b c d e i f g h j
a b c d e i f g h j
PMA
serial interface
serial interface
1250 million baud
1250 million baud
13
AutoNegotiation

• A link protocol which automatically
• Selects Full/Half duplex operation
• Enables/disables Flow Control
• Selects operating speed for 10/100/1000BASE-T
• Can be extended to select other configuration
  parameters in the future
• Takes about 1 second from power on or cable
  insertion

14
Physical Medium

• 802.3z includes support for
• horizontal runs of multi-mode fiber
  (1000BASE-SX)
• backbone runs of multi-mode fiber (1000BASE-LX)
• backbone runs of single-mode fiber (1000BASE-LX)
• short runs of shielded twisted pair
  (1000BASE-CX)
• 802.3ab includes support for horizontal runs of 4
  pair category 5 unshielded twisted pair
  (1000BASE-T)

15
Physical Medium

• 1000BASE-SX uses short wavelength optics
• 770 to 860 nm (visible, eye safe)
• Originally derived from lasers used in
  compact disc players
• Recent development of Vertical Cavity Surface
  Emitting Lasers (VCSELs) reduces component
  costs
• 1000BASE-SX operates on various grades of fiber
• 62.5 mm MMF with modal bandwidth of ³ 160 MHz.km
• 50 mm MMF with modal bandwidth of ³ 400 MHz.km

16
Physical Medium

• 1000BASE-LX uses long wavelength optics
• 1300 nm (infrared, eye safe)
• Derived from long haul telecommunications lasers
• 1000BASE-LX also operates on various grades of
  fiber
• 62.5 mm MMF with bandwidth of ³ 500 MHz.km
• 50 mm MMF with bandwidth of ³ 400 MHz.km
• single mode fiber

17
Link Distances

10u Single-Mode
1000BASE-LX
50u Multimode
62.5u Multimode

50u Multimode
1000BASE-SX
62.5u Multimode

1000BASE-T
4 pr Cat 5 UTP
Balanced Shielded Cable

1000BASE-CX
//
25m
550m
5 km
220m
100m
500m
Machine Room
Building Backbone
Campus Backbone
Horizontal Wiring
18
Optical Interface Parameters
19
1000BASE-T

• 802.3ab project spun-off from 802.3z in March,
  1997
• Takes advantages of high density, high speed
  silicon
• Transmits bi-directionally on 4 wire pairs to
  achieve full duplex communication (250 Mb/s per
  pair)
• Uses 5 level Pulse Amplitude Modulation signaling
• Employs Digital Signal Processing for
• Echo cancellation
• NEXT cancellation
• Digital adaptive equalization

20
1000BASE-T 4 pair signaling
H Y B R I D
H Y B R I D
T
T
R
R
H Y B R I D
H Y B R I D
T
T
R
R
H Y B R I D
H Y B R I D
T
T
R
R
H Y B R I D
H Y B R I D
T
T
R
R
4 Pair Category 5 UTP
21
Extended Optical LinksLong haul, long wavelength

• Gigabit Ethernet in the WAN
• 1550 nm, uncooled, unisolated DFB laser
• Receiver similar to 1000BASE-LX
• 70 km link distance on ordinary SMF
• An efficient way to light dark fiber
• Not expected to become an IEEE standard

22
GBIC Module Flexibility
SX multimode 275 meters only LX/LH multimode
/ 550 meters / singlemode 10 km
ZX singlemode 70km-100km only
Catalyst 29xx, 4xxx, 5x00, 6x00, 8500, Cisco
7500, 12000 Desktop Wiring Closet to Internet
Backbone
23
10 Gigabit Ethernet

• 802.3 formed a Higher Speed Study Group in March,
  1999
• Charted to generate a Project Authorization
  Request (PAR) for a 10 Gbps Ethernet standard
• High level of interest (100s of participants)
• Next meeting July 6 7, Montreal, PQ

24
10 Gigabit EthernetGeneral Assumptions

• Primarily a Physical Layer standard
• Minimal change to the MAC
• May define a new MII
• A family of physical layers
• 100 meters on MMF
• 10 km on SMF
• 100 km on SMF
• Full Duplex only (CSMA/CD is dead)
• 10 Gbps!

25
10 Gigabit EthernetPhysical Layer Possibilities

• Coding schemes
• Serial 8B/10B
• WDM/CWDM
• Parallel 8B/10B
• Multi-level analog

• Wavelengths
• 850 (VCSEL)
• 1300 (VCSEL, FP, DFB)
• 1550 (FP, DFB)

Lots of choices!
26
10 Gig in the LAN and WAN
27
Link Aggregation

• Leverage existing standards by using parallel
  links
• IEEE P802.3ad Link Aggregation standard in
  development

28

• Gigabit Ethernet Consortium established in July,
  1997 at the University of New Hampshire
  Interoperability Lab
• 25 member companies
• Performs testing during product development cycle
  to verify standards compliance and multi-vendor
  interoperability
• 5 test suites addressing MAC, Flow Control, PCS,
  Auto-Negotiation, interoperability

29
For More Information

• IEEE 802.3 Working Group
• http//grouper.ieee.org/groups/802/3/
• Gigabit Ethernet Alliance
• http//www.gigabit-ethernet.org/
• UNH IOL
• http//www.iol.unh.edu/