F-Tile 25G Ethernet Intel® FPGA IP User Guide

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ID 750198
Date 11/04/2024
Public
Document Table of Contents
Document Table of Contents x
1. About the F-Tile 25G Ethernet Intel FPGA IP User Guide 2. About this IP 3. Getting Started 4. F-Tile 25G Ethernet Intel FPGA IP Parameters 5. Functional Description 6. Reset 7. Interfaces and Signal Descriptions 8. Control, Status, and Statistics Register Descriptions 9. F-Tile 25G Ethernet Intel FPGA IP User Guide Archive 10. Document Revision History for the F-Tile 25G Ethernet Intel FPGA IP User Guide
2. About this IP x
2.1. Release Information 2.2. Features 2.3. Device Family Support 2.4. Performance and Resource Utilization
3. Getting Started x
3.1. Installing and Licensing Intel® FPGA IP Cores 3.2. Specifying the IP Core Parameters and Options 3.3. Simulating the IP Core 3.4. Generated File Structure 3.5. Integrating Your IP Core in Your Design 3.6. Compiling the Full Design and Programming the FPGA
3.1. Installing and Licensing Intel® FPGA IP Cores x
3.1.1. Intel® FPGA IP Evaluation Mode
3.5. Integrating Your IP Core in Your Design x
3.5.1. Pin Assignments 3.5.2. Adding the F-Tile Reference and System PLL Clocks Intel® FPGA IP 3.5.3. Placement Settings for the F-Tile 25G Ethernet Intel FPGA IP Core
4. F-Tile 25G Ethernet Intel FPGA IP Parameters x
4.1. Main Tab Options 4.2. Analog Parameter Tab Options
4.2. Analog Parameter Tab Options x
4.2.1. Analog Parameter Settings
5. Functional Description x
5.1. F-Tile 25G Ethernet Intel FPGA IP Core Functional Description 5.2. User Interface to Ethernet Transmission
5.1. F-Tile 25G Ethernet Intel FPGA IP Core Functional Description x
5.1.1. F-Tile 25G Ethernet Intel FPGA IP TX MAC Datapath 5.1.2. 25 GbE TX PCS 5.1.3. F-Tile 25G Ethernet Intel FPGA IP Core RX MAC Datapath 5.1.4. Link Fault Signaling Interface 5.1.5. 25 GbE RX PCS 5.1.6. Flow Control
5.1.1. F-Tile 25G Ethernet Intel FPGA IP TX MAC Datapath x
5.1.1.1. Frame Padding 5.1.1.2. Preamble Insertion 5.1.1.3. Inter-Packet Gap Generation and Insertion 5.1.1.4. Frame Check Sequence (CRC32) Insertion
5.1.3. F-Tile 25G Ethernet Intel FPGA IP Core RX MAC Datapath x
5.1.3.1. IP Core Preamble Processing 5.1.3.2. IP Core Malformed Packet Handling 5.1.3.3. Length/Type Field Processing
5.1.3.3. Length/Type Field Processing x
5.1.3.3.1. Length Checking 5.1.3.3.2. RX CRC Checking and Dynamic Forwarding
5.1.6. Flow Control x
5.1.6.1. TX Pause/PFC Flow Control Frame Transmission Request 5.1.6.2. XON/XOFF Pause Frames 5.1.6.3. Dynamic Reconfiguration QSF Settings
5.2. User Interface to Ethernet Transmission x
5.2.1. Order of Transmission 5.2.2. Bit Order For TX and RX Datapaths
7. Interfaces and Signal Descriptions x
7.1. TX MAC Interface to User Logic 7.2. RX MAC Interface to User Logic 7.3. Transceivers 7.4. Transceiver Reconfiguration Signals 7.5. Avalon® Memory-Mapped Management Interface 7.6. Dynamic Reconfiguration Interface Signals 7.7. Miscellaneous Status and Debug Signals 7.8. Clock Signals 7.9. Reset Signals
8. Control, Status, and Statistics Register Descriptions x
8.1. TX MAC Registers 8.2. RX MAC Registers 8.3. Pause/PFC Flow Control Registers 8.4. Statistics Registers 8.5. Hard IP Registers
8.4. Statistics Registers x
8.4.1. TX Statistics Registers 8.4.2. RX Statistics Registers
1. About the F-Tile 25G Ethernet Intel FPGA IP User Guide
2. About this IP
3. Getting Started
4. F-Tile 25G Ethernet Intel FPGA IP Parameters
5. Functional Description
6. Reset
7. Interfaces and Signal Descriptions
8. Control, Status, and Statistics Register Descriptions
9. F-Tile 25G Ethernet Intel FPGA IP User Guide Archive
10. Document Revision History for the F-Tile 25G Ethernet Intel FPGA IP User Guide

5.1.3.3.1. Length Checking

The MAC function checks the frame and payload lengths of basic, VLAN tagged, and stacked VLAN tagged frames.

The IP core checks that the frame length is valid—is neither undersized nor oversized. A valid frame length is at least 64 (0x40) bytes and does not exceed the following maximum value for the different frame types:

  • Basic frames—The number of bytes specified in the MAX_RX_SIZE_CONFIG register.
  • VLAN tagged frames—The value specified in the MAX_RX_SIZE_CONFIG register plus four bytes.
  • Stacked VLAN tagged frames—The value specified in the MAX_RX_SIZE_CONFIG register plus eight bytes.

If the length/type field in a basic MAC frame or the client length/type field in a VLAN tagged frame has a value less than 0x600, the IP core also checks the payload length. The IP core keeps track of the payload length as it receives a frame, and checks the length against the relevant frame field. The payload length is valid if it satisfies the following conditions:

  • The actual payload length matches the value in the length/type or client length/type field.
  • Normal frames:
    • Basic frames—the payload length is between 46 (0x2E)and 1536 (0x0600) bytes, excluding 1536.
    • VLAN tagged frames—the payload length is between 42 (0x2A)and 1536 (0x0600), excluding 1536.
    • Stacked VLAN tagged frames—the payload length is between 38 (0x26) and 1536 (0x0600), excluding 1536.
  • Jumbo frames:
    • Jumbo basic frames—the payload length is between 46 (0x2E) and the value specified in the MAX_RX_SIZE_CONFIG register minus 18 bytes.
    • Jumbo VLAN tagged frames—the payload length is between 42 (0x2A) and the value specified in the MAX_RX_SIZE_CONFIG register minus 22 bytes.
    • Jumbo stacked VLAN tagged frames—the payload length is between 38 (0x26) and the value specified in the MAX_RX_SIZE_CONFIG register minus 26 bytes.

The RX MAC does not drop frames with invalid length or invalid payload length. If the frame or payload length is not valid, the MAC function asserts output error bits.

  • l1_rx_error[2]—Undersized frame.
  • l1_rx_error[3]—Oversized frame.
  • l1_rx_error[4]—Payload length error.

If the length field value is greater than the actual payload length, the IP core asserts l1_rx_error[4]. If the length field value is less than the actual payload length, the MAC RX considers the frame to have excessive padding and does not assert l1_rx_error[4].

Note: The MAC has a counter limit of 0xFFFF. For frames with size larger than this value, the MAC asserts oversized frame error regardless of the value programmed into MAX_RX_SIZE_CONFIG. This applies to the TX datapath as well.
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