[802.3ae] WIS defect conditions
We'd like to check people's interpretation of the ANSI T1.416-1999
specification referenced by IEEE 802.3ae with respect to WIS. In
particular, we have some confusion about a number of the defect
coniditions.
In section 7.5 of ANSI T1.416-1999, Path AIS is defined as "an all ones
signal in H1, H1*, H2, H2*, H3 and the entire SPE". Does the SPE need
to be all ones for the whole frame to be classed as a path AIS frame, or
can one just assume that if all the header bytes are all ones, then this
is path AIS?
In section 7.4.1 of ANSI T1.416-1999, Line AIS is defined as a "signal
containing a valid SOH with bits 6, 7 and 8 of the K2 byte set to 111,
and a scrambled all-ones pattern for the remainder of the signal". Does
the remainder of the signal mean the whole frame is all ones, apart from
SOH (and therefore including K2[6:8] as this is in line overhead), or is
it just referring to the SPE?
In section 7.3 of ANSI T1.416-1999, SEF defect is defined... very
badly! According to this spec, the occurrence of four or five
consecutive errored frame alignment words will cause that frame to be
marked as SEF. However, two consecutive error-free frame alignment
words will terminate the error. If that is the case, then if ten error
frame alignment words are detected, followed by ten error-free frame
alignment words, then this would mean that the frame is no longer in
error, because the error is terminated. Correct? This seems very
strange to me, and I can't believe it is correct.
If anybody can clear any of these issues up for us, that would be
excellent.
Cheers
Gareth