Altera 40-Gbps Ethernet MAC and PHY MegaCore Function - Manual (Page 67)

40-100GbE IP Core RX Datapath
The 40-100GbE RX MAC receives Ethernet frames from the PHY and forwards the payload with relevant
header bytes to the client after performing some MAC functions on header bytes.
Figure 3-18: Flow of Frame Through the MAC RX Without Preamble Pass-Through
Illustrates the typical flow of frame through the MAC RX when the preamble pass-through feature is
turned off. In this figure, <p> is payload size (0–1500 bytes), and <s> is the number of pad bytes (0–46
bytes).
Client - MAC Rx Interface
Client Frame
MAC Frame
Destination
Addr[47:0] Source
Addr[47:0]
Type/
Length[15:0]
Payload
[<p-1>:0]
Destination
Addr[47:0]
SFD[7:0]
Preamble
[47:0]
CRC32
[31:0]
PAD [<s>-1:0]
Source
Addr[47:0]
Start[7:0] EFD[7:0]
Figure 3-19: Flow of Frame Through the MAC RX With Preamble Pass-Through Turned On
Illustrates the typical flow of frame through the MAC RX when the preamble pass-through feature is
turned on. In this figure, <p> is payload size (0–1500 bytes), and <s> is the number of pad bytes (0–46
bytes).
Client - MAC Rx Interface
Client Frame
MAC Frame
Destination
Addr[47:0] Source
Addr[47:0]
Type/
Length[15:0]
Payload
[<p-1>:0]
Destination
Addr[47:0]
SFD[7:0]
Preamble
[47:0]
CRC32
[31:0]
PAD [<s>-1:0]
Source
Addr[47:0]
Start[7:0]
SFD[7:0]
Preamble
[47:0]
Start[7:0]
EFD[7:0]
The following sections describe the functions performed by the RX MAC:
40-100GbE IP Core RX Filtering on page 3-21
40-100GbE IP Core Preamble Processing on page 3-21
40-100GbE IP Core FCS (CRC-32) Removal on page 3-22
40-100GbE IP Core CRC Checking on page 3-22
RX CRC Forwarding on page 3-22
RX Automatic Pad Removal Control on page 3-22
Address Checking on page 3-24
Inter-Packet Gap on page 3-24
Pause Ignore on page 3-24
3-20 40-100GbE IP Core RX Datapath
UG-01088
2014.12.15
Altera Corporation Functional Description
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