At the physical layer (Layer 1), an Ethernet physical layer device (PHY) connects the
optical or copper media to the MAC layer through a connectivity technology.
Ethernet architecture further divides the physical layer into three sublayers: Physical
Medium Dependent (PMD), Physical Medium Attachment (PMA), and Physical
Coding Sublayer (PCS). PMDs provide the physical connection and signaling to the
medium. The PCS performs encoding and decoding (e.g., 8B/10B) of the data streams
to and from the MAC layer .The PMA serializes multi-bit code groups into a single
bit stream and vice versa. The IEEE 802.3ae standard defines two PHY types: the
LAN PHY and the WAN PHY. They provide the same functionality, except the
WAN PHY has an extended feature in the PCS, that enables the SONET connection.
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APPLICATION
RECONCILIATION
XGMII
NETWORK
PHYSICAL
LAN
GSMAfCQ
LAYERS
HIGHER LAYERS
LUC—LOGICAL LINK CONTROL
MAC C O NTROL (OPTIONAL)
MAC
E
RECONCILIATION j
W
— M— A W W — A M M
XGMII— ► g a
XAUI ■
X G X S
H
X G X S
XGMII-
P C S
PMA
MDI •
PMD
Ed
O ptional XGMII
Extendar*
PHY
MAC — MEDIA A C C E SS CONTROL
MDI = MEDIUM DEPENDENT INTERFACE
P C S = PHYSICAL CODING SUBLAYER
PH Y = PHYSICAL LAYER DEVICE
j
M E D IU M -^ -
P M A - PHYSICAL MEDIUM ATTACHMENT
PM D = PHYSICAL MEDIUM DEPENDENT
XAUI = 1 0 GIGABIT ATTACHMENT UNIT INTERFACE
XGMII = 1 0 GIGABIT MEDIA INDEPENDENT INTERFACE
X G X S = XGMII EXTENDER SUBLAYER
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