[802.3ae] Clarification of local faults
In MDIO mappings,
PMD local fault, PMD transmit local fault, and PMD receive local fault functions
are defined. See for example 52.4.6, .8, & .9.
Last week, Fibre
channel debated the meaning of "local" without clear conclusion. Should local
mean there is something faulty strictly within the PMD (bad component, etc.) or
that the PMD is unable to successfully communicate regardless of cause.
With no
intention of being exhaustive, here are some examples:
1. Should
signal detect = FAIL be considered PMD receive local fault?
2. Should signal
detect = FAIL be considered PMD local fault?
Mechanisms behind
signal detect = FAIL could include a disabled remote transmitter, a broken
cable, a bad photodiode, etc. All prevent successful communication, but only the
latter is a fault truly within the PMD.
3. Should assertion
of transmit disable be considered PMD transmit local
fault?
4. Should assertion
of transmit disable be considered PMD local fault?
Again, this will prevent communication, yet it is
not due to a problem within the PMD.
Thanks,
Tom Lindsay
Stratos NW
425/672-8035 x105