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We inject Local and Remote faults via the Reconciliation SubLayer by sending an ordered set indicating a local or remote fault.

For 10G:

All these details would be defined in Clause 46, 802.3ae.

For 50,100G,200G and 400G:

We used Clause 81, 802.3ba - Subclause 81.3.4

For 10G / Clause 46:

For 100G / Clause 81.3.4 Link Fault Signaling:

Link fault signaling operates between the remote RS and the local RS. Faults detected between the remote RS and the local RS are received by the local RS as Local Fault. Only an RS originates Remote Fault signals. The behavior of the fault signaling is the same as it is for Clause 46 with the exception that the ordered sets are aligned to eight byte boundaries, padding lanes 4 to 7 with 0x00.

Clause 46 uses the term column when describing data transfers on the XGMII. The eight lanes of data and control transferred per clock cycle on XLGMII/CGMII are equivalent to a column in the following description of link fault signaling.

Sublayers within the PHY are capable of detecting faults that render a link unreliable for communication. Upon recognition of a fault condition, a PHY sublayer indicates Local Fault status on the data path. When this Local Fault status reaches an RS, the RS stops sending MAC data, and continuously generates a Remote Fault status on the transmit data path (possibly truncating a MAC frame being transmitted). When Remote Fault status is received by an RS, the RS stops sending MAC data, and continuously generates Idle control characters. When the RS no longer receives fault status messages, it returns to normal operation, sending MAC data. Note that this behavior only supports bidirectional operation.

Status is signaled in an eight byte Sequence ordered_set as shown in Table 81–5. The PHY indicates Local Fault with a Sequence control character in lane 0 and data characters of 0x00 in lanes 1, 2, 4, 5, 6, and 7 plus a data character of 0x01 in lane 3. The RS indicates a Remote Fault with a Sequence control character in lane 0 and data characters of 0x00 in lanes 1, 2, 4, 5, 6, and 7 plus a data character of 0x02 in lane 3. Though most fault detection is on the receive data path of a PHY, in some specific sublayers, faults can be detected on the transmit side of the PHY. This is also indicated by the PHY with a Local Fault status. All other values in lanes 1 to 3 not shown in Table 81–5 are reserved. The link fault signaling state diagram allows future standardization of reserved Sequence ordered sets for functions other than link fault indications.
 

 

 

Table 81-5 - Sequence ordered_sets

The RS reports the fault status of the link. Local Fault indicates a fault detected on the receive data path between the remote RS and the local RS. Remote Fault indicates a fault on the transmit path between the local RS and the remote RS. The RS shall implement the link fault signaling state diagram (see Figure 81–9).

The operation of fault is the same between Clause 46 and Clause 81, except in Clause 81 the ordered sets are aligned to eight byte boundaries, padding lanes 4 to 7 with 0x00.