Low Latency Ethernet 10G MAC Intel® FPGA IP User Guide: Agilex™ 3 and Agilex™ 5 FPGAs and SoCs
Visible to Intel only — GUID: bhc1395127686406
Ixiasoft
Visible to Intel only — GUID: bhc1395127686406
Ixiasoft
3.5.4. Frame Type Checking
The MAC RX checks the length/type field to determine the frame type:
- Length/type < 0x600—The field represents the payload length of a basic Ethernet frame. The MAC RX continues to check the frame and payload lengths.
- Length/type >= 0x600—The field represents the frame type.
- Length/type = 0x8100—VLAN or stacked VLAN tagged frames (up to a total of two tags with value 0x8100). The MAC RX continues to check the frame and payload lengths.
- Length/type = 0x8808—Control frames. The next two bytes are the Opcode field which indicates the type of control frame. For pause frames (Opcode = 0x0001) and PFC frames (Opcode = 0x0101), the MAC RX proceeds with pause frame processing. By default, the MAC RX drops all control frames. If configured otherwise (FWD_CONTROL bit in the rx_frame_control register = 1), the MAC RX forwards control frames to the client.
- For other field values, the MAC RX forwards the receive frame to the client.
Category | Packet Size | Length/Type = Payload | Length/Type > Payload | Length/Type < Payload | MAC Behavior | |
---|---|---|---|---|---|---|
Frame Drop | avalon_st_rx_error[] | |||||
Normal packet | 64–1518 | Yes | No | No | No | — |
No | No | Yes | No | |||
No | Yes | No | No | avalon_st_rx_error[4] = 1 |
||
Undersized | Packet < 64 | Yes | No | No | No | avalon_st_rx_error[2] = 1 |
No | No | Yes | No | |||
No | Yes | No | No | avalon_st_rx_error[2] = 1 avalon_st_rx_error[4] = 1 |
||
Oversized | 1518 < Packet < 1535 | Yes | No | No | No | avalon_st_rx_error[3] = 1 |
No | No | Yes | No | |||
No | Yes | No | No | avalon_st_rx_error[3] = 1 avalon_st_rx_error[4] = 1 |