100 Gigabit Ethernet

40 Gigabit Ethernet, or 40GbE, and 100 Gigabit Ethernet, or 100GbE, are high-speed computer network standards developed by the Institute of Electrical and Electronics Engineers (IEEE). They support sending Ethernet frames at 40 and 100 gigabits per second over multiple 10 Gb/s or 25 Gb/s lanes. Previously, the fastest published Ethernet standard was 10 Gigabit Ethernet. They were first studied in November 2007, proposed as IEEE 802.3ba in 2008, and ratified in June 2010. Another variant was added in March 2011.

History

In June 2007 a trade group called “Road to 100G” was formed after the NXTcomm trade show in Chicago. Official standards work was started by IEEE 802.3 Higher Speed Study Group. The P802.3ba Ethernet Task Force commenced on December 5, 2007 with the following project authorization request:

The purpose of this project is to extend the 802.3 protocol to operating speeds of 40 Gb/s and 100 Gb/s in order to provide a significant increase in bandwidth while maintaining maximum compatibility with the installed base of 802.3 interfaces, previous investment in research and development, and principles of network operation and management. The project is to provide for the interconnection of equipment satisfying the distance requirements of the intended applications.

Physical Standards

The 40/100 Gigabit Ethernet standards encompass a number of different Ethernet physical layer (PHY) specifications. A networking device may support different PHY types by means of pluggable modules. Optical modules are not standardized by any official standards body but are in multi-source agreements (MSAs). One agreement that supports 40 and 100 Gigabit Ethernet is the C Form-factor Pluggable (CFP) MSA which was adopted for distances of 100+ meters. QSFP and CXP connector modules support shorter distances.

The standard supported only full-duplex operation. Other electrical objectives include:

• Preserve the 802.3 / Ethernet frame format utilizing the 802.3 MAC
• Preserve minimum and maximum FrameSize of current 802.3 standard
• Support a bit error ratio (BER) better than or equal to 10 ^{− 12} at the MAC/PLS service interface
• Provide appropriate support for OTN
• Support MAC data rates of 40 and 100 Gbit/s
• Provide Physical Layer specifications (PHY) for operation over single-mode optical fiber (SMF), laser optimized multi-mode optical fiber (MMF) OM3 and OM4, copper cable assembly, and backplane.

The following nomenclature was used for the physical layers:

Physical layer	40 Gigabit Ethernet	100 Gigabit Ethernet
at least 1 m over a backplane	40GBASE-KR4
approximately 7 m over copper cable	40GBASE-CR4	100GBASE-CR10
at least 100 m over OM3 MMF	40GBASE-SR4	100GBASE-SR10
at least 125 m over OM4 MMF
at least 10 km over SMF	40GBASE-LR4	100GBASE-LR4
at least 40 km over SMF		100GBASE-ER4
serial SMF over 2 km	40GBASE-FR

The 100 m laser optimized multi-mode fiber (OM3) objective was met by parallel ribbon cable with 850 nm wavelength 10GBASE-SR like optics (40GBASE-SR4 and 100GBASE-SR10). The 1 m backplane objective with 4 lanes of 10GBASE-KR type PHYs (40GBASE-KR4). The 10 m copper cable objective is met with 4 or 10 differential lanes using SFF-8642 and SFF-8436 connectors. The 10 and 40 km 100G objectives with four wavelengths (around 1310 nm) of 25G optics (100GBASE-LR4 and 100GBASE-ER4) and the 10 km 40G objective with four wavelengths (around 1310 nm) of 10G optics (40GBASE-LR4).

In January 2010 another IEEE project authorization started a task force to define a 40 gigabit per second serial single-mode optical fiber standard (40GBASE-FR). This was approved as standard 802.3bg in March 2011. It used 1550 nm optics, had a reach of 2 km and was capable of receiving 1550 nm and 1310 nm wavelengths of light. The capability to receive 1310 nm light allows it to inter-operate with a longer reach 1310 nm PHY should one ever be developed. 1550 nm was chosen as the wavelength for 802.3bg transmission to make it compatible with existing test equipment and infrastructure.

In December 2010, a 10×10 Multi Source Agreement (10×10 MSA) began to define an optical Physical Medium Dependent (PMD) sublayer and establish compatible sources of low-cost, low-power, pluggable optical transceivers based on 10 optical lanes at 10 gigabits/second each. The 10×10 MSA was intended as an lower cost alternative to 100GBASE-LR4 for applications which do not require a link length longer than 2 km. It was intended for use with standard single mode G.652.C/D type low water peak cable with ten wavelengths ranging from 1523 to 1595 nm. The founding members were Google, Brocade Communications, JDSU and Santur. Other member companies of the 10×10 MSA included MRV, Enablence, Cyoptics, AFOP, OPLINK, Hitachi Cable America, AMS-IX, EXFO, Huawei, Kotura, Facebook and Effdon when the 2 km specification was anounced in March 2011. The 10X10 MSA modules were intended to be the same size as the C Form-factor Pluggable specifications.

Backplane

NetLogic Microsystems announced backplane modules in October 2010. This industry trend is important because standards-based 100GE interconnects may allow building optical backplanes at a fraction of price currently required by VCSEL based implementations – such as those in found in multichassis systems from Cisco (CRS) and Juniper Networks (T-series).

Copper cables

Quellan announced a test board, but no module is available.

Multimode fiber

In 2009, Mellanox and Reflex Photonics announced modules based on the CFP agreement.

Single Mode fiber

Finisar, Sumitomo Electric Industries, and OpNext  all demonstrated singlemode 40 or 100 Gigabit Ethernet modules based on the C Form-factor Pluggable agreement at the European Conference and Exhibition on Optical Communication in 2009.

Compatibility

• Optical domain IEEE 802.3ba implementations were not compatible with the numerous 40G and 100G line rate transport systems which feature different optical layer and modulation formats.
• In particular, existing 40 Gigabit transport solutions that used dense wavelength-division multiplexing to pack four 10 Gigabit signals into one optical medium were not compatible with the IEEE 802.3ba standard, which used either coarse WDM in 1310 nm wavelength region with four 25 Gigabit or four 10 Gigabit channels, or parallel optics with four or ten optical fibers per direction

Test and Measurement

• Ixia developed Physical Coding Sublayer Lanes and announced test equipment in 2009.
• JDS Uniphase introduced test and measurement products for 40 and 100 Gigabit Ethernet in 2009. Discovery Semiconductors introduced optoelectronics converters for 100 gigabit testing of the 10 km and 40 km Ethernet standards.
• Spirent Communications introduced test and measurement products in 2009 and 2010. Xena Networks demonstrated test equipment at the Technical University of Denmark in January 2011. EXFO demonstrated interoperability in January 2010.
• These products verify Ethernet protocol implementation but do not test physical layer compliance to IEEE PMD specifications.

 

Standardization Time Line

IEEE standardization project history:

• Call for interest at IEEE 802.3 plenary meeting in San Diego — July 18, 2006
• First HSSG study group meeting — September 2006
• Last study group meeting — November 2007
• Task Force formally approved as P802.3ba by IEEE LMSC — December 5, 2007
• First P802.3ba task force meeting — January 2008
• IEEE 802.3 working group ballot — March 2009
• IEEE LMSC sponsor ballot — November 2009
• First 40 Gbit/s Ethernet Single-mode Fiber PMD study group meeting — January 2010.
• P802.3bg task force approved for 40 Gbit/s serial SMF PMD— March 25, 2010
• IEEE 802.3ba standard approved — June 17, 2010
• IEEE 802.3bg standard approved — March 2011
• IEEE 802.3bj 100 Gb/s Backplane and Copper Cable Task Force PAR approval due — September 2011

P802.3ba Task Force draft release dates:

• Draft 1.0 — October 1, 2008
• Draft 1.1 — December 9, 2008
• Draft 1.2 — February 10, 2009
• Draft 2.0 — March 12, 2009 (for working group ballot)
• Draft 2.1 — May 29, 2009
• Draft 2.2 — August 15, 2009
• Draft 2.3 — October 14, 2009
• Draft 3.0 — November 18, 2009 (for sponsor group ballot)
• Draft 3.1 — February 10, 2010
• Draft 3.2 — March 24, 2010
• Final — June 17, 2010

System Diagrams for different standards of Ethernet

IEEE 802.3 Communication Standards’ Chart

Ethernet Standard	Date	Description
Experimental Ethernet	1973	2.94 Mbit/s (367 kB/s) over coaxial cable (coax) cable bus
Ethernet II (DIX v2.0)	1982	10 Mbit/s (1.25 MB/s) over thick coax. Frames have a Type field. This frame format is used on all forms of Ethernet by protocols in the Internet protocol suite.
IEEE 802.3	1983	10BASE5 10 Mbit/s (1.25 MB/s) over thick coax. Same as Ethernet II (above) except Type field is replaced by Length, and an 802.2 LLC header follows the 802.3 header
802.3a	1985	10BASE2 10 Mbit/s (1.25 MB/s) over thin Coax (a.k.a. thinnet or cheapernet)
802.3b	1985	10BROAD36
802.3c	1985	10 Mbit/s (1.25 MB/s) repeater specs
802.3d	1987	Fiber-optic inter-repeater link
802.3e	1987	1BASE5 or StarLAN
802.3i	1990	10BASE-T 10 Mbit/s (1.25 MB/s) over twisted pair
802.3j	1993	10BASE-F 10 Mbit/s (1.25 MB/s) over Fiber-Optic
802.3u	1995	100BASE-TX, 100BASE-T4, 100BASE-FX Fast Ethernet at 100 Mbit/s (12.5 MB/s) w/autonegotiation
802.3x	1997	Full Duplex and flow control; also incorporates DIX framing, so there’s no longer a DIX/802.3 split
802.3y	1998	100BASE-T2 100 Mbit/s (12.5 MB/s) over low quality twisted pair
802.3z	1998	1000BASE-X Gbit/s Ethernet over Fiber-Optic at 1 Gbit/s (125 MB/s)
802.3-1998	1998	A revision of base standard incorporating the above amendments and errata
802.3ab	1999	1000BASE-T Gbit/s Ethernet over twisted pair at 1 Gbit/s (125 MB/s)
802.3ac	1998	Max frame size extended to 1522 bytes (to allow “Q-tag”) The Q-tag includes 802.1Q VLAN information and 802.1p priority information.
802.3ad	2000	Link aggregation for parallel links, since moved to IEEE 802.1AX
802.3-2002	2002	A revision of base standard incorporating the three prior amendments and errata
802.3ae	2003	10 Gbit/s (1,250 MB/s) Ethernet over fiber; 10GBASE-SR, 10GBASE-LR, 10GBASE-ER, 10GBASE-SW, 10GBASE-LW, 10GBASE-EW
802.3af	2003	Power over Ethernet (12.95 W)
802.3ah	2004	Ethernet in the First Mile
802.3ak	2004	10GBASE-CX4 10 Gbit/s (1,250 MB/s) Ethernet over twin-axial cable
802.3-2005	2005	A revision of base standard incorporating the four prior amendments and errata.
802.3an	2006	10GBASE-T 10 Gbit/s (1,250 MB/s) Ethernet over unshielded twisted pair (UTP)
802.3ap	2007	Backplane Ethernet (1 and 10 Gbit/s (125 and 1,250 MB/s) over printed circuit boards)
802.3aq	2006	10GBASE-LRM 10 Gbit/s (1,250 MB/s) Ethernet over multimode fiber
P802.3ar	Cancelled	Congestion management (withdrawn)
802.3as	2006	Frame expansion
802.3at	2009	Power over Ethernet enhancements (25.5 W)
802.3au	2006	Isolation requirements for Power Over Ethernet (802.3-2005/Cor 1)
802.3av	2009	10 Gbit/s EPON
802.3aw	2007	Fixed an equation in the publication of 10GBASE-T (released as 802.3-2005/Cor 2)
802.3-2008	2008	A revision of base standard incorporating the 802.3an/ap/aq/as amendments, two corrigenda and errata. Link aggregation was moved to 802.1AX.
802.3az	2010	Energy Efficient Ethernet
802.3ba	2010	40 Gbit/s and 100 Gbit/s Ethernet. 40 Gbit/s over 1m backplane, 10m Cu cable assembly (4×25 Gbit or 10×10 Gbit lanes) and 100 m of MMF and 100 Gbit/s up to 10 m of Cu cable assembly, 100 m of MMF or 40 km of SMF respectively
802.3-2008/Cor 1	2009	Increase Pause Reaction Delay timings which are insufficient for 10G/sec (workgroup name was 802.3bb)
802.3bc	2009	Move and update Ethernet related TLVs (type, length, values), previously specified in Annex F of IEEE 802.1AB (LLDP) to 802.3.
802.3bd	2010	Priority-based Flow Control. A amendment by the IEEE 802.1 Data Center Bridging Task Group (802.1Qbb) to develop an amendment to IEEE Std 802.3 to add a MAC Control Frame to support IEEE 802.1Qbb Priority-based Flow Control.
802.3.1	2011	MIB definitions for Ethernet. It consolidates the Ethernet related MIBs present in Annex 30A&B, various IETF RFCs, and 802.1AB annex F into one master document with a machine readable extract. (workgroup name was P802.3be)
802.3bf	2011	Provide an accurate indication of the transmission and reception initiation times of certain packets as required to support IEEE P802.1AS.
802.3bg	2011	Provide a 40 Gbit/s PMD which is optically compatible with existing carrier SMF 40 Gbit/s client interfaces (OTU3/STM-256/OC-768/40G POS).
P802.3ah	~Mar 2012	A revision of base standard incorporating the 802.3at/av/az/ba/bc/bd/bf/bg amendments, a corrigenda and errata. (Expected to be published as 802.3-2012)

10 GBASE-T

• 10 GE, 10GbE, 10GigE
• Uses unshielded twisted-pair wiring
• 100 m
• Cat 6a
• Full duplex echo cancelled transmission
• 833 Mbaud, ~450MHz used BW
• FEXTcancellation required
• FEC codes
• LDPC block codes
• RJ45 connectors
• 10 level PAM coded signaling (3 information bits / symbol)
• 8 state 4D Trellis code across pairs

Physical Coding Sublayer (PCS)

The interface between the PCS and the RS is the XGMII. The 10GBASE-X PCS provides services to the XGMII in a manner analogous to how the 1000BASE-X PCS provides services to the 1000 Mb/s GMII. The 10GBASE-X PCS provides all services required by the XGMII and in support of the 10GBASE-X PMA, including:

a) Encoding of 32 XGMII data bits and 4 XGMII control bits to four parallel lanes conveying 10-bit code-groups each, for communication with the underlying PMA.

b) Decoding of four PMA parallel lanes, conveying 10-bit code-groups each, to 32 XGMII data bits and 4 XGMII control bits.

c) Synchronization of code-groups on each lane to determine code-group boundaries.

d) Deskew of received code-groups from all lanes to an alignment pattern.

e) Support of the MDIO interface and register set as specified in Clause 45 to report status and enable control of the PCS.

f) Conversion of XGMII Idle control characters to (from) a randomized sequence of code-groups to enable serial lane synchronization, clock rate compensation and lane-to-lane alignment.

g) Clock rate compensation protocol.

h) Link Initialization based on the transmission and reception of the Idle sequence.

i) Link status reporting for fault conditions.

Physical Medium Attachment (PMA) sublayer

The PMA provides a medium-independent means for the PCS to support the use of a range of serial-bit-oriented physical media. The 10GBASE-X PMA performs the following functions:

a) Mapping of transmit and receive code-groups between the PCS and PMA via the PMA service interface.

b) Serialization (deserialization) of code-groups for transmission (reception) on the underlying serial PMD.

c) Clock recovery from the code-groups supplied by the PMD.

d) Mapping of transmit and receive bits between the PMA and PMD via the PMD service interface.

e) Direct passing of signal_detect from the PMD to the PCS through the PMA via the PMD and PMA service interfaces.

Physical Medium Dependent (PMD) sublayer

10GBASE-X uses the PMD sublayer and MDI. The 10GBASE-CX4, 10GBASE-KX4, and 10GBASE-LX4 perform the following functions:

a) Transmission of quad serial bit streams on the underlying medium.

b) Reception of quad serial bit streams on the underlying medium.

Allocation of functions

PCS and PMA functions directly map onto the 10GBASE-X PMD, MDI and medium which attach, in turn, to another 10GBASE-X PHY.

The longer interconnect distances afforded through the specification of self-clocked serial architecture enable significant implementation flexibility while imposing a requirement on those implementations to ensure sufficient signal fidelity over the link.

Inter-sublayer interfaces

There are a number of interfaces employed by 10GBASE-X. Some (such as the PMA service interface) use an abstract service model to define the operation of the interface. Multiple optional physical instantiations of the PCS
service interface have been defined.

Blocks

I. Reconciliation

II. XGMII

III. PCS

IV. FEC

V. PMA

VI. PMD

VII. AUTONEG

VIII. MDI

Actual connector

Protocol Structure – 10 Gigabit Ethernet: The Ethernet Protocol IEEE 802.3ae for LAN, WAN and MAN 10 Gigabit Ethernet uses the same MAC frame as the Ethernet

7	1	6	6	2	46=<1500< b>	4
Pre	SFD	DA	SA	Length Type	Data unit + pad	FCS

• Preamble (PRE)– 7 bytes. The PRE is an alternating pattern of ones and zeros that tells receiving stations that a frame is coming, and that provides a means to synchronize the frame-reception portions of receiving physical layers with the incoming bit stream.
• Start-of-frame delimiter (SFD)– 1 byte. The SOF is an alternating pattern of ones and zeros, ending with two consecutive 1-bits indicating that the next bit is the left-most bit in the left-most byte of the destination address.
• Destination address (DA)– 6 bytes. The DA field identifies which station(s) should receive the frame..
• Source addresses (SA)– 6 bytes. The SA field identifies the sending station.
• Length/Type– 2 bytes. This field indicates either the number of MAC-client data bytes that are contained in the data field of the frame, or the frame type ID if the frame is assembled using an optional format.
• Data– Is a sequence of nbytes (46=< n =<1500) of any value. (The total frame minimum is 64bytes.)
• Frame check sequence (FCS)– 4 bytes. This sequence contains a 32-bit cyclic redundancy check (CRC) value, which is created by the sending MAC and is recalculated by the receiving MAC to check for damaged frames.

1000 BASE-T

• PAM-5 coded signaling (2 information bits /symbol)
• 8 state 4D Trelis code across pairs
• Full duplex echo cancelled transmission
• 125 Mbaud, ~80MHz used BW
• No FEXT cancellation
• At least Category 5 cable, with Category 5estrongly recommended copper cabling with four twisted pairs. Each pair is used in both directions simultaneously
• Gigabit Ethernet access methods include half-duplex using traditional CSMA/CD (not common) and full-duplex (most popular method)
• The Gigabit Ethernet reconciliation sublayer is responsible for sending 8-bit parallel data to the PHY sublayer via a GMII interface.
• The Gigabit Ethernet GMII defines how the reconciliation sublayer is to be connected to the PHY sublayer.
• The Gigabit Ethernet PHY sublayer is responsible for encoding and decoding.
• MAC Frame with Gigabit Ethernet Carrier Extension (IEEE 803.3z)
• 1000Base-X has a minimum frame size of 416bytes, and 1000Base-T has a minimum frame size of 520bytes. The Extension is a non-data variable extension field to frames that are shorter than the minimum length.

7	1	6	6	2	Variable	4	Variable
Pre	SFD	DA	SA	Length Type	Data unit + pad	FCS	Ext

Repeater

• A repeater set is an integral part of any Gigabit
• Ethernet network with more than two DTEs in a collision domain
• A repeater set extends the physical system topology by coupling two or more segments. Only one repeater is permitted within a single collision domain

Auto-Negotiation, type 1000BASE-T

• Auto-Negotiation is used by 1000BASE-T devices to detect the abilities (modes of operation) supported by the device at the other end of a link segment, determine common abilities, and configure for joint operation.
• Auto-Negotiation is performed upon link startup through the use of a special sequence of fast link pulses.

Management

Managed objects, attributes, and actions are defined for all Gigabit Ethernet components.

Physical Coding Sublayer (PCS)

The PCS interface is the Gigabit Media Independent Interface (GMII) that provides a uniform interface to the Reconciliation sublayer for all 1000 Mb/s PHY implementations. The 1000BASE-X PCS provides all services required by the GMII, including

a) Encoding (decoding) of GMII data octets to (from) ten-bit code-groups (8B/10B) for communication with the underlying PMA

b) Generating Carrier Sense and Collision Detect indications for use by PHY’s half duplex clients

c) Managing the Auto-Negotiation process, and informing the management entity via the GMII when the PHY is ready for use

Physical Medium Attachment (PMA) sublayer

The PMA provides a medium-independent means for the PCS to support the use of a range of serial-bit-oriented physical media. The 1000BASE-X PMA performs the following functions:

a) Mapping of transmit and receive code-groups between the PCS and PMA via the PMA Service Interface

b) Serialization (deserialization) of code-groups for transmission (reception) on the underlying serial PMD

c) Recovery of clock from the 8B/10B-coded data supplied by the PMD

d) Mapping of transmit and receive bits between the PMA and PMD via the PMD Service Interface

e) Data loopback at the PMD Service Interface

Physical Medium Dependent (PMD) sublayer

1000BASE-X adapts these basic Physical Layer specifications for use with the PMD sublayer and mediums. The MDI, logically
subsumed within each PMD subclause, is the actual medium attachment, including connectors, for the various supported media.

Inter-sublayer interfaces

There are a number of interfaces employed by 1000BASE-X.
Some (such as the PMA Service Interface) use an abstract service model to define the operation of the interface. An optional physical instantiation of the PCS Interface has been defined. It is called the GMII (Gigabit Media Independent Interface). An optional physical instantiation of the PMA Service Interface has also been defined.

Blocks

I. Reconciliation

II. GMII

III. PCS

IV. PMA

V. PMD

VI. AUTONEG

VII. MDI

Actual Connector

Carrier Extension is a simple solution, but it wastes bandwidth. Packet Bursting is “Carrier Extension plus a burst of packets”. Burst mode is a feature that allows a MAC to send a short sequence (a burst) of frames equal to approximately 5.4 maximum length frames without having to relinquish control of the medium.

The Gigabit Ethernet standards are fully compatible with Ethernet and Fast Ethernet installations. It retains Carrier Sense Multiple Access/ Collision Detection (CSMA/CD) as the access method. It supports full-duplex as well as half duplex modes of operation. Single-mode and multi mode fiber and short-haul coaxial cable, and twisted pair cables are supported.

Protocol Structure – Gigabit (1000 Mbps) Ethernet: IEEE 802.3z (1000Base-X) and 802.3ab (1000Base-T) and GBIC

1000Base-X has a minimum frame size of 416bytes, and 1000Base-T has a minimum frame size of 520bytes. An extension field is used to fill the frames that are shorter than the minimum length.

7	1	6	6	2	46=< n =<1500	4	Variable
Pre	SFD	DA	SA	Length Type	Data unit + pad	FCS	Ext

• Preamble (PRE)– 7 bytes. The PRE is an alternating pattern of ones and zeros that tells receiving stations that a
  frame is coming, and that provides a means to synchronize the frame-reception portions of receiving physical layers with the incoming bit stream.
• Start-of-frame delimiter (SFD)– 1 byte. The SOF is an alternating pattern of ones and zeros, ending with two consecutive 1-bits indicating that the next bit is the left-most bit in the left-most byte of the destination address.
• Destination address (DA)– 6 bytes. The DA field identifies which station(s) should receive the frame..
• Source addresses (SA)– 6 bytes. The SA field identifies the sending station.
• Length/Type– 2 bytes. This field indicates either the number of MAC-client data bytes that are contained in the data field of the frame, or the frame type ID if the frame is assembled using an optional format.
• Data– Is a sequence of n bytes (46=< n =<1500) of any value. The total frame minimum is 64bytes.
• Frame check sequence (FCS)– 4 bytes. This sequence contains a 32-bit cyclic redundancy check (CRC) value, which is created by the sending MAC and is recalculated by the receiving MAC to check for damaged frames.
•  Ext – extension, which is an non-data variable extension field for frames that are shorter than the minimum length

100 BASE-T

• autonegotiation allows two devices to negotiate the mode or data rate of operation
• Fast Ethernet reconciliation sub layer is responsible for the passing of data in 4-bit format to the MII
• The Fast Ethernet MII is an interface that can be used with both a 10- and a 100-Mbps interface
• Fast Ethernet PHY sub layer is responsible for encoding and decoding.
• 4B5B mLT- coded signaling, CAT5 copper cabling with two twisted pairs
• 100 m
• Cat 5

Repeater

• Repeater sets are an integral part of any 100BASE-T network with more than two DTEs in a collision domain.
• They extend the physical system topology by coupling two or more segments.
• Multiple repeaters are permitted within a single collision domain to provide the maximum path length.
• Auto-Negotiation provides a linked device with the capability to detect the abilities (modes of operation) supported by the device at the other end of the link, determine common abilities, and configure for joint operation.

Auto-Negotiation

• Auto-Negotiation is performed out-of-band using a pulse code sequence

Management

• Managed objects, attributes, and actions are defined for all 100BASE-T components.

Physical Coding Sublayer (PCS)

The PCS interface is the Media Independent Interface (MII) that provides a uniform interface to the Reconciliation sublayer for all 100BASE-T PHY implementation. 100BASE-X, as other 100BASE-T PHYs, is modeled as providing services to the MII. The 100BASE-X PCS realizes all services required by the MII, including:

a) Encoding (decoding) of MII data nibbles to (from) five-bit code-groups (4B/5B);

b) Generating Carrier Sense and Collision Detect indications;

c) Serialization (deserialization) of code-groups for transmission (reception) on the underlying serial PMA, and

d) Mapping of Transmit, Receive, Carrier Sense and Collision Detection between the MII and the underlying PMA

Physical Medium Attachment (PMA) sublayer

The PMA provides a medium-independent means for the PCS and other bit-oriented clients (e.g., repeaters) to support the use of a range of physical media. The 100BASE-X PMA performs the following functions:

a) Mapping of transmit and receive code-bits between the PMA’s client and the underlying PMD;

b) Generating a control signal indicating the availability of the PMD to a PCS or other client, also synchronizing with Auto-Negotiation when implemented;

c) Optionally, generating indications of activity (carrier) and carrier errors from the underlying PMD;

d) Optionally, sensing receive channel failures and transmitting the Far-End Fault Indication; and detecting the Far-End Fault Indication; and

e) Recovery of clock from the NRZI data supplied by the PMD.

Physical Medium Dependent (PMD) sublayer

100BASE-X uses the FDDI signaling standards ISO/IEC 9314-3:1990 and ANSI X3.263-1995 (TP-PMD). These signaling standards, called PMD sublayers, define 125 Mb/s, full duplex signaling systems that accommodate multimode optical fiber, STP and UTP wiring.

Inter-sublayer interfaces

There are a number of interfaces employed by 100BASE-X. Some (such as the PMA and PMD interfaces) use an abstract service model to define the operation of the interface. The PCS Interface is defined as a set of physical signals, in a medium-independent manner (MII).

Blocks

I. Reconciliation

II. MII

III. PCS & PMA

IV. PMD

V. AUTONEG

optional

VI. MDI

Actual connector

The Fast Ethernet specifications include mechanisms for Auto-Negotiation of the media speed. This makes it possible for vendors to provide dual-speed Ethernet interfaces that can be installed and run at either 10-Mbps or 100-Mbps automatically.

Protocol Structure – Fast Ethernet: 100Mbps Ethernet (IEEE 802.3u)The basic IEEE 802.3 Ethernet MAC Data Frame for 10/100Mbps Ethernet:

7	1	6	6	2	46 =< n =< 1500	4bytes
Pre	SFD	DA	SA	Length Type	Data unit + pad	FCS

• Preamble (PRE)– 7 bytes. The PRE is an alternating pattern of ones and zeros that tells receiving stations that a
  frame is coming, and that provides a means to synchronize the frame-reception portions of receiving physical layers with the incoming bit stream.
• Start-of-frame delimiter (SFD)– 1 byte. The SOF is an alternating pattern of ones and zeros, ending with two
  consecutive 1-bits indicating that the next bit is the left-most bit in the left-most byte of the destination address.
• Destination address (DA)– 6 bytes. The DA field identifies which station(s) should receive the frame..
• Source addresses (SA)– 6 bytes. The SA field identifies the sending station.
• Length/Type– 2 bytes. This field indicates either the number of MAC-client data bytes that are contained in the
  data field of the frame, or the frame type ID if the frame is assembled using an optional format.
• Data– Is a sequence of n bytes (46=< n =<1500) of any value. (The total frame minimum is 64bytes.)
• Frame check sequence (FCS)– 4 bytes. This sequence contains a 32-bit cyclic redundancy check (CRC) value, which is created by the sending MAC and is recalculated by the receiving MAC to check for damaged frames.

10BASE-T

• Manchester coded signaling
• copper twisted pair cabling
• star topology
• full duplex
• 100 m
• RJ 45 connectors
• Cat 3, 4, 5, 53, 4 wire (2 twisted pairs)

 

Blocks
I. Reconciliation
Optional her, must on 100Base T
II. MII
optional
III. PLS
Provides logical and functional coupling b/w MAU and data link layer
IV. AUI
V. PMA
VI. MDI
Actual Connector
Protocol Structure – Ethernet: IEEE 802.3 Local Area Network protocols.The basic IEEE 802.3 Ethernet MAC Data Frame for 10/100Mbps Ethernet:

7	1	6	6	2	46-1500bytes	4
Pre	SFD	DA	SA	Length Type	Data unit + pad	FCS

• Preamble (PRE)- 7 bytes. The PRE is an alternating pattern of ones and zeros that tells receiving stations that a frame is coming, and that provides a means to synchronize the frame-reception portions of receiving physical layers with the incoming bit stream.
• Start-of-frame delimiter (SFD)- 1 byte. The SOF is an alternating pattern of ones and zeros, ending with two consecutive 1-bits indicating that the next bit is the left-most bit in the left-most byte of the destination address.
• Destination address (DA)- 6 bytes. The DA field identifies which station(s) should receive the frame..
• Source addresses (SA)- 6 bytes. The SA field identifies the sending station.
• Length/Type– 2 bytes. This field indicates either the number of MAC-client data bytes that are contained in the data field of the frame, or the frame type ID if the frame is assembled using an optional format.
• Data– Is a sequence of n bytes (46=< n =<1500) of any value. (The total frame minimum is 64bytes.)
• Frame check sequence (FCS)- 4 bytes. This sequence contains a 32-bit cyclic redundancy check (CRC) value, which is created by the sending MAC and is recalculated by the receiving MAC to check for damaged frames.