AN 846: Intel® Stratix® 10 Forward Error Correction

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ID 683805
Date 7/02/2018
Public
Document Table of Contents
Document Table of Contents x
1. Introduction 2. Necessity of Error Correction 3. FEC Selection 4. FEC in Intel® Stratix® 10 H-Tile Devices 5. FEC in Intel® Stratix® 10 E-Tile Devices 6. FEC Implementation Using the E-Tile Channel Placement Tool 7. FEC in Practical Application 8. Hardware Results 9. Document Revision History for AN 846: Intel® Stratix® 10 Forward Error Correction
2. Necessity of Error Correction x
2.1. Solutions to Transmission Errors 2.2. Error Correction Codes 2.3. What is FEC?
2.1. Solutions to Transmission Errors x
2.1.1. Parity and Cyclic Redundancy Check 2.1.2. Error Correction Code (ECC) Block Coding
2.3. What is FEC? x
2.3.1. FEC Definitions
3. FEC Selection x
3.1. Key Considerations when Choosing a FEC
4. FEC in Intel® Stratix® 10 H-Tile Devices x
4.1. Fire Code (802.3ap, 10GBASE-KR)
4.1. Fire Code (802.3ap, 10GBASE-KR) x
4.1.1. FEC Block Format 4.1.2. FEC Block Composition 4.1.3. FEC Sublayer for BASE-R PHYs 4.1.4. L-Tile/H-Tile Implementation
4.1.4. L-Tile/H-Tile Implementation x
4.1.4.1. Transcode Encoder 4.1.4.2. KR FEC Encoder 4.1.4.3. KR FEC Scrambler 4.1.4.4. KR FEC TX Gearbox 4.1.4.5. KR FEC RX Gearbox 4.1.4.6. Transcode Decoder
5. FEC in Intel® Stratix® 10 E-Tile Devices x
5.1. Types of RS-FEC 5.2. 100GBASE-KR4 5.3. 100GBASE-KP4 5.4. FEC Decoders 5.5. Specifications 5.6. Functions Within the RS-FEC Sublayer
5.1. Types of RS-FEC x
5.1.1. RS (528, 514, t = 7, m = 10) 5.1.2. RS (544, 514, t = 15, m = 10) 5.1.3. Supported RS-FEC Modes in E-Tile Devices
5.2. 100GBASE-KR4 x
5.2.1. 100GBASE-KR4 Mapping (IEEE802.3bj Clause 91)
5.3. 100GBASE-KP4 x
5.3.1. 100GBASE-KP4 Mapping (IEEE802.3bj Clause 91)
5.6. Functions Within the RS-FEC Sublayer x
5.6.1. Lane Block Synchronization 5.6.2. Alignment Lock and Deskew 5.6.3. Lane Re-order 5.6.4. Alignment Marker Removal 5.6.5. 64B/66B to 256B/257B Transcoder
7. FEC in Practical Application x
7.1. Datacenter Applications Scenario
8. Hardware Results x
8.1. Test Design 8.2. Test Setup 8.3. Insertion Loss Plots 8.4. FEC Statistics Tool 8.5. Hardware Data 8.6. Comparison to the Specification 8.7. References
1. Introduction
2. Necessity of Error Correction
3. FEC Selection
4. FEC in Intel® Stratix® 10 H-Tile Devices
5. FEC in Intel® Stratix® 10 E-Tile Devices
6. FEC Implementation Using the E-Tile Channel Placement Tool
7. FEC in Practical Application
8. Hardware Results
9. Document Revision History for AN 846: Intel® Stratix® 10 Forward Error Correction

5.3.1. 100GBASE-KP4 Mapping (IEEE802.3bj Clause 91)

Figure 18. 100GBASE-KP4 Mapping
  • RS (544, 514, 15, 10) FEC
  • 26.5625 Gbps
  • 3.03% rate expansion
  • Data is stripped per symbol across four lanes

RS(544, 514) requires additional room to accommodate 5440 bits instead of 5280 bits. After transcoding, it must additionally make room for approximately 3% more bits of overhead. The precise overhead is calculated as 1/33; new rate = old rate * 34/33. This result is overspeed for PAM4. For example:

  • Payload data rate = 50 Gbps
  • Encoding it to 66b encoding: 50*66/64 = 51.5625 Gbps
  • Adding FEC expansion: 51.5625*(34/33) = 53.125 Gbps

Intel® Stratix® 10TX devices do not support the 100GBASE-KP4 physical medium dependent (PMD).

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