IEEEStd802.3™-2008(RevisionofIEEEStd802.3-2005)Section4

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IEEE Standard for Information technology—

Telecommunications and information exchange between systems—

Local and metropolitan area networks—

Specific requirements

Part 3: Carrier Sense Multiple Access with

Collision Detection (CSMA/CD) access method

and Physical Layer specifications

SECTION FOUR: This section includes Clause 44 through Clause 55 and Annex 44A through

Annex 55B.

44. Introduction to 10 Gb/s baseband network

44.1 Overview

44.1.1 Scope

10 Gigabit Ethernet uses the IEEE 802.3 MAC sublayer, connected through a 10 Gigabit Media Independent

Interface (XGMII) to Physical Layer entities such as 10GBASE-SR, 10GBASE-LX4, 10GBASE-CX4,

10GBASE-LRM, 10GBASE-LR, 10GBASE-ER, 10GBASE-SW, 10GBASE-LW, 10GBASE-EW, and

10GBASE-T.

10 Gigabit Ethernet extends the IEEE 802.3 MAC beyond 1000 Mb/s to 10 Gb/s. The bit rate is faster and

the bit times are shorter—both in proportion to the change in bandwidth. The minimum packet transmission

time has been reduced by a factor of ten. A rate control mode (see 4.2.3.2.2) is added to the MAC to adapt

the average MAC data rate to the SONET/SDH data rate for WAN-compatible applications of this standard.

Achievable topologies for 10 Gb/s operation are comparable to those found in 1000BASE-X full duplex

mode and equivalent to those found in WAN applications.

10 Gigabit Ethernet is defined for full duplex mode of operation only.

44.1.2 Objectives

The following are the objectives of 10 Gigabit Ethernet:

a) Support the full duplex Ethernet MAC.

b) Provide 10 Gb/s data rate at the XGMII.

c) Support LAN PMDs operating at 10 Gb/s, and WAN PMDs operating at SONET STS-192c/SDH

VC-4-64c rate.

d) Support cable plants using optical fiber compliant with ISO/IEC 11801:1995.

e) Allow for a nominal network extent of up to 40 km.

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IEEE

Std 802.3-2008 REVISION OF IEEE Std 802.3:

f) Support operation over a twinaxial cable assembly for wiring closet and data center applications.

g) Support operation over selected copper media from ISO/IEC 11801:2002.

h) Support a BER objective of 10

–12

44.1.3 Relationship of 10 Gigabit Ethernet to the ISO OSI reference model

10 Gigabit Ethernet couples the IEEE 802.3 (CSMA/CD) MAC to a family of 10 Gb/s Physical Layers. The

relationships among 10 Gigabit Ethernet, the IEEE 802.3 (CSMA/CD) MAC, and the ISO Open System

Interconnection (OSI) reference model are shown in Figure 44–1.

It is important to note that, while this specification defines interfaces in terms of bits, octets, and frames,

implementations may choose other data-path widths for implementation convenience. The only exceptions

are as follows:

a) The XGMII, which, when implemented at an observable interconnection port, uses a four octet-wide

data path as specified in Clause 46.

b) The management interface, which, when physically implemented as the MDIO/MDC (Management

Data Input/Output and Management Data Clock) at an observable interconnection port, uses a bit-

wide data path as specified in Clause 45.

c) The PMA Service Interface, which, when physically implemented as the XSBI (10 Gigabit Sixteen

Bit Interface) at an observable interconnection port, uses a 16-bit-wide data path as specified in

Clause 51.

d) The MDI as specified in Clause 53 for 10GBASE-LX4, in Clause 54 for 10GBASE-CX4, in

Clause 55 for 10GBASE-T, in Clause 68 for 10GBASE-LRM, and in Clause 52 for other PMD

types.

Figure 44–1—Architectural positioning of 10 Gigabit Ethernet

MDI

MDI = MEDIUM DEPENDENT INTERFACE

PMD = PHYSICAL MEDIUM DEPENDENT

LAN

CSMA/CD

LAYERS

LLC (LOGICAL LINK CONTROL) OR OTHER MAC CLIENT

MAC—MEDIA ACCESS CONTROL

RECONCILIATION

HIGHER LAYERS

10GBASE-R

PMD

MAC CONTROL (OPTIONAL)

PRESENTATION

APPLICATION

SESSION

TRANSPORT

NETWORK

DATA LINK

PHYSICAL

OSI

REFERENCE

MODEL

LAYERS

MEDIUM

PMA

64B/66B PCS

10GBASE-W

PMD

MEDIUM

64B/66B PCS

PMA

WIS

XGMII

10GBASE-X

PMD

MEDIUM

PMA

8B/10B PCS

WIS = WAN INTERFACE SUBLAYER

XGMII = 10 GIGABIT MEDIA INDEPENDENT INTERFACE

PCS = PHYSICAL CODING SUBLAYER

PMA = PHYSICAL MEDIUM ATTACHMENT

PHY = PHYSICAL LAYER DEVICE

PHY

10GBASE-T

MDI

MEDIUM

XGMII

PMA

LDPC PCS

AN = AUTO-NEGOTIATION SUBLAYER

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IEEE

CSMA/CD Std 802.3-2008

44.1.4 Summary of 10 Gigabit Ethernet sublayers

44.1.4.1 Reconciliation Sublayer (RS) and 10 Gigabit Media Independent Interface (XGMII)

The 10 Gigabit Media Independent Interface (Clause 46) provides an interconnection between the Media

Access Control (MAC) sublayer and Physical Layer entities (PHY). This XGMII supports 10 Gb/s operation

through its 32-bit-wide transmit and receive data paths. The Reconciliation Sublayer provides a mapping

between the signals provided at the XGMII and the MAC/PLS service definition.

While the XGMII is an optional interface, it is used extensively in this standard as a basis for functional

specification and provides a common service interface for Clause 47, Clause 48, Clause 49, and Clause 55.

44.1.4.2 XGMII Extender Sublayer (XGXS) and 10 Gigabit Attachment Unit Interface (XAUI)

The 10 Gigabit Attachment Unit Interface (Clause 47) provides an interconnection between two XGMII

Extender sublayers to increase the reach of the XGMII. This XAUI supports 10 Gb/s operation through its

four-lane, differential-pair transmit and receive paths. The XGXS provides a mapping between the signals

provided at the XGMII and the XAUI.

44.1.4.3 Management interface (MDIO/MDC)

The MDIO/MDC management interface (Clause 45) provides an interconnection between MDIO Manage-

able Devices (MMD) and Station Management (STA) entities.

44.1.4.4 Physical Layer signaling systems

This standard specifies a family of Physical Layer implementations. The generic term 10 Gigabit Ethernet

refers to any use of the 10 Gb/s IEEE 802.3 MAC (the 10 Gigabit Ethernet MAC) coupled with any IEEE

802.3 10GBASE Physical Layer implementation. Table 44–1 specifies the correlation between nomencla-

ture and clauses. Implementations conforming to one or more nomenclatures shall meet the requirements of

the corresponding clauses.

Table 44–1—Nomenclature and clause correlation

Nomenclature

Clause

48 49 50 51 52 53 54 55 68

8B/10B

PCS &

PMA

64B/66B

PCS

WIS Serial

PMA

850 nm

Serial

PMD

1310 nm

Serial

PMD

1550 nm

Serial

PMD

1310 nm

WDM

PMD

4-Lane

electrical

PMD

Twisted-

pair PCS

& PMA

1310 nm

Serial

MMF

PMD

10GBASE-SR M

M = Mandatory

10GBASE-SW M M M M

10GBASE-LX4 M M

10GBASE-CX4 M M

10GBASE-LR M M M

10GBASE-LW M M M M

10GBASE-ER M M M

10GBASE-EW M M M M

10GBASE-T M

10GBASE-LRM M M M

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IEEE

Std 802.3-2008 REVISION OF IEEE Std 802.3:

The term 10GBASE-X, specified in Clause 48, Clause 53, and Clause 54, refers to a specific family of Phys-

ical Layer implementations based upon 8B/10B data coding method. The 10GBASE-X family of Physical

Layer implementations is composed of 10GBASE-LX4 and 10GBASE-CX4.

The term 10GBASE-R refers to a specific family of Physical Layer implementations. The 10GBASE-R

family of Physical Layer implementations based upon 64B/66B data coding method is composed of

10GBASE-SR, 10GBASE-LR, 10GBASE-ER, and 10GBASE-LRM.

The term 10GBASE-W, specified in Clause 49 through Clause 52, refers to a specific family of Physical

Layer implementations based upon STS-192c/SDH VC-4-64c encapsulation of 64B/66B encoded data. The

10GBASE-W family of Physical Layer standards has been adapted from the ANSI T1.416-1999 (SONET

STS-192c/SDH VC-4-64c) Physical Layer specifications. The 10GBASE-W family of Physical Layer

implementations is composed of 10GBASE-SW, 10GBASE-LW, and 10GBASE-EW.

All 10GBASE-R and 10GBASE-W PHY devices share a common PCS specification (see Clause 49). The

10GBASE-W PHY devices also require the use of the WAN Interface Sublayer, (WIS) (Clause 50).

The term 10GBASE-T, specified in Clause 55, refers to a specific Physical Layer implementation based

upon 64B/65B data coding placed in a low density parity check (LDPC) frame that is mapped to a 128

double-square (DSQ128) constellation for transmission on 4-pair, twisted-pair copper cabling.

Physical Layer device specifications are contained in Clause 52, Clause 53, Clause 54, Clause 55, and

Clause 68.

44.1.4.5 WAN Interface Sublayer (WIS), type 10GBASE-W

The WIS provides a 10GBASE-W device with the capability to transmit and receive IEEE 802.3 MAC

frames within the payload envelope of a SONET STS-192c/SDH VC-4-64c frame.

44.1.5 Management

Managed objects, attributes, and actions are defined for all 10 Gigabit Ethernet components. Clause 30 con-

solidates all IEEE 802.3 management specifications so that 10/100/1000 Mb/s and 10 Gb/s agents can be

managed by existing network management stations with little or no modification to the agent code.

44.2 State diagrams

State diagrams take precedence over text.

The conventions of 1.2 are adopted, along with the extensions listed in 21.5.

44.3 Delay constraints

Predictable operation of the MAC Control PAUSE operation (Clause 31, Annex 31B) demands that there be

an upper bound on the propagation delays through the network. This implies that MAC, MAC Control

sublayer, and PHY implementors must conform to certain delay maxima, and that network planners and

administrators conform to constraints regarding the cable topology and concatenation of devices. Table 44–2

contains the values of maximum sublayer round-trip (sum of transmit and receive) delay in bit time as

specified in 1.4 and pause_quanta as specified in 31B.2.

Equation (44–1) specifies the calculation of bit time per meter of fiber or electrical cable based upon the

parameter n, which represents the ratio of the speed of electromagnetic propagation in the fiber or electrical

cable to the speed of light in a vacuum. The value of n should be available from the fiber or electrical cable

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