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Re: Question about Link Fault Signalling

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A picture is worth a thousand words ...

Attached is a pdf of the state diagram for RS link status management.


From: "David Gross" <dgross@xxxxxxxxxxxxxxxxxx>

Ben, Bob,

I also like the idea of not requiring some # of IDLEs to exit a fault
condition. If the fault no longer occurs that should cause the exit.

I do have a bit of a simple question, but I'd like to ask it just for

When we say that "the reception of four status messages of the same type

shall indicate that the corresponding fault condition has occurred" I
interpret this to be within a time period of 4 clocks - that is 8
recieved groups. This seems to make sense if the recieved message is
alternated with IDLE characters (if IDLEs are deleted for timing, it
doesn't matter since we'll get 4 fault messages sooner). Since there was

no wording describing how long we have to detect the four fault messages

I thought I'd mention it just to be certain. Please correct me if my
assumption is wrong. Thanks.


Ben Brown wrote:
> Bob,
> I'll go one step further, in line with a recent note from Rich.
> The presence or absence of LF or RF ordered sets should decide
> what state the RS is in. Requiring some number of IDLEs to
> exit a state is undesirable (in my opinion). The case where
> a MAC is sending data when an RS leaves the LF state results
> in the link partner seeing RF followed directly by packets.
> Though this first packet will likely be trashed (and I have
> no problem with that), it should not require 8 words of IDLEs
> to exit the RF state, resulting in the loss of perhaps many
> packets if they all have minimum IPGs.
> Ben

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