Visible to Intel only — GUID: lbl1458082003842
Ixiasoft
Visible to Intel only — GUID: lbl1458082003842
Ixiasoft
4.1.4. Link Fault Signaling Interface
You enable link fault signaling by turning on Enable link fault generation in the parameter editor. For bidirectional fault signaling, the IP core implements the functionality defined in the IEEE 802.3ba 10G Ethernet Standard and Clause 46 based on the LINK_FAULT configuration register settings.
For unidirectional fault signaling, the core implements Clause 66 of the IEEE 802.3-2012 Ethernet Standard.Local Fault (LF)
If an Ethernet PHY sublayer detects a fault that makes the link unreliable, it notifies the RS of the local fault condition. If unidirectional is not enabled, the core follows Clause 46. The RS stops sending MAC data, and continuously generates a remote fault status on the TX datapath. After a local fault is detected, the RX PCS modifies the MII data and control to send local fault sequence ordered sets. Refer to Link Fault Signaling Based On Configuration and Status below.
The RX PCS cannot recognize the link fault under the following conditions:
- The RX PCS is not fully aligned.
- The bit error rate (BER) is high.
Remote Fault (RF)
If unidirectional is not enabled, the core follows Clause 46. If the RS receives a remote fault status, the TX datapath stops sending MAC data and continuously generates idle control characters. If the RS stops receiving fault status messages, it returns to normal operation, sending MAC client data. Refer to Link Fault Signaling Based On Configuration and Status below.
Link Status Signals
LINK_FAULT Register (0x405) | Real Time Link Status | Configured TX Behavior | Comment | |||||
---|---|---|---|---|---|---|---|---|
Bit [0] | Bit [3] | Bit [1] | Bit [2] | LF Received |
RF Received |
TX Data |
TX RF |
|
1'b0 | Don't care | Don't care | Don't care | Don’t care | Don’t care | On | Off | Disable Link fault signaling on TX. RX still reports link status. TX side Link fault signaling disabled on the link. TX data and idle. |
1'b1 | 1'b1 | Don't care | Don't care | Don't care | Don't care | Off | On | Force RF. TX: Stop data. Transmit RF only |
1'b1 | 1'b0 | 1'b1 | 1'b1 | Don't care | Don't care | On | Off | Unidir: Backwards compatible. TX: Transmit data and idle. No RF. |
1'b1 | 1'b0 | 1'b1 | 1'b0 | 1'b1 | 1'b0 | On | On | Unidir: LF received. TX: Transmit data 1 column IDLE after end of packet and RF |
1'b1 | 1'b0 | 1'b1 | 1'b0 | 1'b0 | 1'b1 | On | Off | Unidir: RF receives TX: Transmit data and idle. No RF. |
1'b1 | 1'b0 | 1'b1 | 1'b0 | 1'b0 | 1'b0 | On | Off | Unidir: No link fault TX: Transmit data and idle. No RF. |
1'b1 | 1'b0 | 1'b0 | Don't care | 1'b1 | 1'b0 | Off | On | Bidir: LF received TX: Stop data. Transmit RF only. |
1'b1 | 1'b0 | 1'b0 | Don't care | 1'b0 | 1'b1 | Off | Off | Bidir: RF received TX: Stop data. Idle only. No RF. |
1'b1 | 1'b0 | 1'b0 | Don’t care | 1'b0 | 1'b0 | On | Off | Bidir: No link fault TX: Transmit data and idle. No RF. |
At this time, the 25G Ethernet Intel FPGA IP core does not recognize received non-zero 4-bit ordered set types as an error.