Trung tâm đào tạo thiết kế vi mạch Semicon

 

    Gigabit Ethernet Description

      The Ethernet standard uses Manchester Encoding and Decoding. Access control is gained via Carrier Sense, Multiple Access with Collision Detect (CSMA_CD). However 10 Gigabit Ethernet [10GE] only uses Full-duplex, so CSMA/CD is not required. Preamble Field:

A 56 bit pattern of alternating ones and zeros which are used to synchronize the receiver clock to the incoming data packet. SFD Field: Start Frame Delimiter Field, indicates the beginning of the frame; [10101011].

Ethernet Packet

1000Base-T. [Gigabit Ethernet] operates up to 100 meters on EIA568, 4-pair [CAT-5] UTP [Un-Shielded Twisted Pair] 100 ohm copper wiring. This is backwards compatible with 100Base-T. Also uses Fibre Channel as the physical layer, and runs at 1000Mbps, using 8B/10B encoding [10 bits = 1 byte].

10Gb Attachment Unit Interface [Gigabit Ethernet XAUI] is used as an interface extender for 10-gigabit media-independent interface [XGMII]. The XAUI interface is a backplane interface, Chip-to-Chip interface, or board interface. XAUI uses four full-duplex serial links operating at 3.125 Gbps in each direction. In aggregate, a total of 12.5 Gbps can be transferred in each direction.

The Gigabit Media Independent Interface [GMII] is the interface between the Media Access Controller [MAC] layer and Physical Layer and is divided into three sublayers : PCS, PMA and PMD. The MII [Media Independent Interface] was developed for Fast Ethernet.
Physical Coding Sublayer [PCS] is the GMII sub-layer responsible for the interface to the Reconciliation layer. The PCS layer uses 8B/10B encoding.
Physical Medium Attachment [PMA] is the GMII sub-layer responsible for providing a medium-independent for the PCS to support serial bit-oriented physical media. This layer serializes code groups for transmission and deserializes bits received from the medium into code groups. The Gigabit Ethernet PMA interface is identical to the PMA interface used in FiberChannel, but the difference is FiberChannel utilizes 1.062-gigabaud signaling while Gigabit Ethernet utilizes 1.25-gigabaud signaling. Encoding is 8B/10B.
Physical Medium Dependent [PMD] is the GMII sub-layer responsible for mapping the physical medium to the PCS. The Medium Dependent Interface [MDI] is the physical layer interface, and is part of the PMD.

10Gb Sixteen-Bit Interface [XSBI], WAN Interface Sublayer [WIS], XAUI Extender Sublayer [XGXS],

The frame check sequence is derived from a Cyclic Redundancy Code (CRC); the coefficients are generated modulo-2:
X31 + X26 + X23 + X22 + X16 + X12 + X11 + X10 + X8 + X7 + X5 + X4 +X2 + X + 1

10Base Ethernet is listed on the Ethernet Bus page, which contains a description and additional links

{Gigabit Ethernet Interface Bus Index}

---

Ethernet Bus 1000BaseT RJ45 Pin Out

Ethernet 1000BaseT (Twisted Pair Pinout)

Pin #	Signal Name	Function
1	BI_DA+	Bi-directional pair +A
2	BI_DA-	Bi-directional pair -A
3	BI_DB+	Bi-directional pair +B
4	BI_DC+	Bi-directional pair +C
5	BI_DC-	Bi-directional pair -C
6	BI_DB-	Bi-directional pair -B
7	BI_DD+	Bi-directional pair +D
8	BI_DD-	Bi-directional pair -D

The pinout table above describes what some call the CAT-5 pinout as found on an RJ-45 connector. The CAT-5 pinout pairs 1/2, 3/6, 4/5, and 7/8 pins together. Another version of the pinout is called the Standard pinout and also uses an RJ45 connector. The standard pin out pairs pins 1/2, 3/4, 5/6, and 7/8 together.

The MII interface pinout is listed on it's own page [Media-independent interface].
Refer to the AUI Pinout page for the pin out of the AUI connector, used with older Ethernet interfaces.

{Gigabit Ethernet Interface Index}

---