IP/Network

  

 

 

 

Ethernet : 10 GbE(Gigabit Ethernet)

 

10 Gigabit Ethernet (10GbE) is a standard that enables the transfer of Ethernet frames at speeds of up to 40 gigabits per second (Gbps).

 

10GbE fulfill the following requirements and objectives: (According to IEEE 802.3 Section 4). The most outstanding feature would be that 10Gb support Full duplex only. Half Duplex is not supported

  • Support Full Duplex Ethernet MAC

  • Provide 10 Gb Data Rate at XGMII

  • Support LAN PMDs operating at 10 Gbs and WAN PMDs operating at SONET STS-192c/SDH VC-4-64c rate
  • Support cable plants using cabled optical fiber compliant with ISO/IEC 11801:1995
  • Allow for a nominal network extent of up to 40 km
  • Support operation over a twinaxial cable assembly for wiring closet and data center applications
  • Support operation over selected copper media from ISO/IEC 11801:2002
  • Support a BER objective of 10^-12

 

Overal Phyical layer for 10GbE is structured as shown below in IEEE 802.3 Section 4.

According to 802.3 Section 4 : Figure 44–1, the overall architecture of 10 Gbps Ethernet is illustrated as follows. As shown here, 10Gbps Ethernet can be implemented over 4 different types of media W(WAN), R(LAN), X(LAN) and T(Twisted Pair).

 

 

 

 

 

Each of these four media type has a couple of sub types and all of those sub types and related section number in 802.3-section 4 is summarizied in following table in 802.3 Section 4 : Table 44–1.

 

 

In this table, you see several new letters like S,L,C,E,R and these letters indicates followings.

  • C = Copper (two axial) 

  • S = Short 

  • L = Long  

  • E = Extended  

  • Z = Ultra extended

  • T = Copper(UTP)

  • M = Multimode

  • 4 = 4 WWDM wavelengths or 4 XAUI lanes  

Applying the medium type shown in architecture diagram and the nomenclature(naming) table, you can summarize each of the 10Gb ethernet type as follows. Just write down features marked as 'M' from each row(10Gb type).

 

Type

Description

10GBASE-SR

PCS(Physical Coding Sublayer) = 64B/66B

PMA(Physical Medium Attachement) = Serial

PMD(Physical Medium Dependent) = Optical, 850 nm Serial

10GBASE-SW

PCS(Physical Coding Sublayer) = 64B/66B  

PMA(Physical Medium Attachement) = Serial

WAN Interface Sublayer (WIS)

PMD(Physical Medium Dependent) = Optical, 850 nm Serial

10GBASE-LX4

PCS(Physical Coding Sublayer) & PMA(Physical Medium Attachement) = 8B/10B

PMD(Physical Medium Dependent) = Optical, 1310 nm WDMl

10GBASE-CX4

PCS(Physical Coding Sublayer) & PMA(Physical Medium Attachement) = 8B/10B

PMD(Physical Medium Dependent) = 4 lane electrical

10GBASE-LR

PCS(Physical Coding Sublayer) = 64B/66B

PMA(Physical Medium Attachement) = Serial

PMD(Physical Medium Dependent) = Optical, 1310 nm Serial

10GBASE-LW

PCS(Physical Coding Sublayer) = 64B/66B  

PMA(Physical Medium Attachement) = Serial

WAN Interface Sublayer (WIS)

PMD(Physical Medium Dependent) = Optical, 1310 nm Serial

10GBASE-ER

PCS(Physical Coding Sublayer) = 64B/66B

PMA(Physical Medium Attachement) = Serial

PMD(Physical Medium Dependent) = Optical, 1550 nm Serial

10GBASE-EW

PCS(Physical Coding Sublayer) = 64B/66B  

PMA(Physical Medium Attachement) = Serial

WAN Interface Sublayer (WIS)

PMD(Physical Medium Dependent) = Optical, 1550 nm Serial

10GBASE-T

PCS(Physical Coding Sublayer) & PMA(Physical Medium Attachement) = Twisted Pair

10GBASE-LRM

PCS(Physical Coding Sublayer) = 64B/66B

PMA(Physical Medium Attachement) = Serial

PMD(Physical Medium Dependent) = Optical, 1310 nm Serial MMF

 

 

 

Here goes the neatly summarized comparison between 1Gb Ethernet and 10Gb Ethernet (Following table is from IEEE 802 10GBASE-T Tutorial Tutorial shared by IEEE).

 

1000 BASE-T (1Gb)

10GBASE-T
5-level coded PAM signaling (2 information bits/symbol) 10-level coded PAM signaling(3 information bits/simbol)
8-state 4D Trellis code across pairs 8-state 4D Trellis code across pairs
Full duplex echo-cancelled transmission Full duplex echo-cancelled transmission
125 Mbaud, ~80 Mhz used bandwidth 833 Mbaud, ~450 Mhz used bandwidth
No FEXT Cancellation FEXT Cancellation Required

 

Throughput : 4 (lanes) x 833 Mbaud x 3 bits/baud = 10Gb/s

 

 

 

Reference :

 

[1] 802.3-Section 4 : IEEE Standard for Ethernet

[2] Difference between 10GBASE-T,10GBASE-R,10GBASE-X and 10GBASE-W  

[3] Ethernet Tutorial - Fujitsu

[4] 1000BASE-X Physical Coding Sublayer (PCS) and Physical Medium Attachment (PMA) Tutorial

[5] 10 Gigabit Ethernet and the XAUI interface