400GE FEC Encode/Decode Processing€¦ · is mandatory. See how a 400GBASE-R Reed-Solomon RS-544...
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© Keysight Technologies 2018. All rights reserved. 5992-3405EN. October 11, 2018 400GE FEC Encode/Decode Processing The IEEE 802.3bs Task Group defines specifications for 400 Gigabit per second (Gb/s) Ethernet, where forward error correction (FEC) is mandatory. See how a 400GBASE-R Reed-Solomon RS-544 (KP4 FEC) encode/decode works in operation. Note that FEC encoding/decoding takes place at the binary level before the physical layer. Stay informed about Keysight Data Center Infrastructure Solutions. www.keysight.com/find/DCIS TRANSMIT PATH RECEIVE PATH Transmit Transcoder Reduces line encoding overhead Gearboxing facilitates FEC symbol boundaries IEEE 802.3bs specifies 16 PCS lanes across both 400GAUI-16 & 400GAUI-8 electrical interfaces 256b/257b scrambled 256b/257b Pre-FEC Symbol Distributor Symbol = 10 bits PCS Lane Transmit MAC Scrambler Self-synchronizes, ensures no long runs of 1s & 0s Different markers are created for each of the 16 PCS lanes 64/66 64/66 64/66 64/66 64/66 bit Codewords ... Alignment Marker Group Insertion ... ... ... 257 320 FEC a KP4 FEC Encoding 30 check symbols are calculated & inserted per FEC codeword FEC Codeword Interleaving & Distribution FEC b 0 1 2 ... 14 13 12 ... ... ... ... ... ... 3 ... 15 ... Gray Encoder 0 1 7 8 8 PAM4 Lanes at 53 Gb/s to PHY Transmitter LEARN MORE 0 1 7 8 Receive Transcoder Expands bit stream to original 64/66b format Self-synchronizing, reconstitutes original bit stream Descrambler 256b/257b scrambled 256b/257b 0 1 2 ... 15 14 13 PCS Lane ... ... ... ... ... ... 64/66 bit Codewords Alignment Marker Group Removal Corrects up to 15 symbol errors per FEC codeword KP4 FEC Decoding PCS Alignment Marker Lock, Deskew, and Reorder process ... 257 320 FEC De-interleaving Corrected FEC Codeword Interleaving FEC a FEC b Alignment Lock State Machine Deskew FIFO Alignment Lock State Machine Reorder MUX Receive MAC Deskew FIFO 0 1 2 ... 14 13 12 ... ... ... ... ... 3 ... 15 ... Inverse Gray Encoder 8 PAM4 Lanes at 53 Gb/s LEARN MORE PHY Receiver
Transcript of 400GE FEC Encode/Decode Processing€¦ · is mandatory. See how a 400GBASE-R Reed-Solomon RS-544...
© Keysight Technologies 2018. All rights reserved. 5992-3405EN. October 11, 2018
400GE FEC Encode/Decode ProcessingThe IEEE 802.3bs Task Group defines specifications for 400 Gigabit per second (Gb/s) Ethernet, where forward error correction (FEC) is mandatory. See how a 400GBASE-R Reed-Solomon RS-544 (KP4 FEC) encode/decode works in operation. Note that FEC encoding/decoding takes place at the binary level before the physical layer.
Stay informed about Keysight Data Center Infrastructure Solutions. www.keysight.com/find/DCIS
TRANSMIT PATH
RECEIVE PATH
Transmit Transcoder
Reduces line encoding overhead
Gearboxing facilitates FEC symbol boundaries
IEEE 802.3bs specifies 16 PCSlanes across both 400GAUI-16
& 400GAUI-8 electrical interfaces
256b/257b scrambled 256b/257b
Pre-FECSymbol Distributor
Symbol = 10 bits
PCS Lane
TransmitMAC
Scrambler
Self-synchronizes, ensures no long runs of 1s & 0s
Different markers are created for eachof the 16 PCS lanes
64/66
64/66
64/66
64/66
64/66 bit Codewords...
Alignment Marker Group Insertion
......
...
257
320 FEC a
KP4 FEC Encoding
30 check symbols are calculated & inserted
per FEC codeword
FEC CodewordInterleaving
& Distribution
FEC b
012
...
14
13
12.........
...
...
...
3...
15...
Gray Encoder
0
1
7
8
8 PAM4 Lanesat 53 Gb/s
to PHY Transmitter
LEARN MORE
0
1
7
8
Receive Transcoder
Expands bit stream to original
64/66b format
Self-synchronizing, reconstitutes
original bit stream
Descrambler
256b/257bscrambled 256b/257b
012...
151413
PCS Lane
...
...
...
...
...
... 64/66 bit Codewords
Alignment Marker Group Removal
Corrects up to 15symbol errors per FEC
codeword
KP4 FEC Decoding
PCS Alignment
Marker Lock, Deskew, and Reorder process
...
257
320
FEC De-interleaving
Corrected FEC
Codeword Interleaving
FEC a
FEC b
AlignmentLock StateMachine
DeskewFIFO
AlignmentLock StateMachine
ReorderMUX
ReceiveMAC
DeskewFIFO
012
...
14
13
12.........
...
...
3...
15...
InverseGray Encoder
8 PAM4 Lanesat 53 Gb/s
LEARN MORE
PHYReceiver
