RE: [802.3ae] Link Fault Signalling
The RS only forces the transmit path to Remote Fault or Idle. It never
generates Local Fault. The PCS only forces the data path to Local Fault
(whether toward the RS or toward the fiber). At a RS receive (i.e., the
link fault state machine), reception of Local Fault causes the transmit path
RS to force Remote Fault; and reception of Remote Fault causes the transmit
path RS to force Idle.
From: Burt Christian [mailto:burt@xxxxxxxxx]
Sent: Tuesday, December 04, 2001 7:07 PM
To: HSSG (E-mail)
Subject: [802.3ae] Link Fault Signalling
I wanted to ensure that my understanding of the RS Link Fault
Signalling mechanism is correct. I am trying to understand the
mechanism rather than the details of the protocol. If someone
can please confirm the following description to be correct, I
would appreciate it.
1. If a fault on either the transmit path or the receive path
of PMD or PMA is detected then regardless of the quality of
the signal received by the PCS on the receive path, Local
Fault Ordered Sets will be transmitted by the PCS to the RS.
2. Once the RS Link Fault Signalling State Machine (Figure 46-9)
has entered the FAULT state with link_fault == Local Fault, RS
will start transmiting Remote Fault Ordered Sets on the transmit
One thing I would like to confirm is that the Local Fault Ordered
Set will never be transmitted by the RS on the link where the link
is defined as the communication channel between two RS peers. This
is quite clear based on the very last section of 18.104.22.168 but I
would like to ensure that I am not missing anything.
Burt S, Christian.
Tel : (613)599-5797
Fax : (613)599-1247