RE: [EFM] Re: OAM Transport Proposal
David,
Good point. I had overlooked the fact that in 802.3z, the signal detect
does not go above the PCS. Therefore, if we required signal detect for an
alarm indication in OAMinP, we'd either have to adjust the response time
accordingly for the MDIO/MDC access or add another signal to the GMII.
Thanks again for pointing that out.
Cheers,
Brad
-----Original Message-----
From: David Law [mailto:David_Law@xxxxxxxxxxxx]
Sent: Wednesday, April 24, 2002 1:31 PM
To: Booth, Bradley
Cc: stds-802-3-efm@ieee.org
Subject: RE: [EFM] Re: OAM Transport Proposal
Hi Brad,
You interpretation of the intent of the term "pervasive
access" in my
presentation is correct. The management entity has the same,
unspecified, direct
access to the MAC, MAC Control and RS State Machines and
Functions.
I would also like to comment on the your point about
speeding up OAMinP by using
state machines in the RS. In the case of an implementation
where the optional
MDC/MDIO is the only management interface to the PHY layers
below the RS, I
believe that there is some information that is sent by
OAMinP, such as the
signal state, that will not be available in the RS. In this
particular case the
information will have to written to the RS by the management
entity after it is
polled through the MDC/MDIO hence preventing state machine
speed up for that
information. Further, as I believe the standard allows for
the optional MDC/MDIO
to be the only management interface to the PHY layers below
the RS, I think the
minimum response time specification (if included) for
information that is not
available in the RS would have to allow for this polling
delay. Alternatively of
course, further changes to the interfaces could be made.
Best regards,
David Law
"Booth, Bradley" <bradley.booth@xxxxxxxxx> on 24/04/2002
17:45:03
Sent by: "Booth, Bradley" <bradley.booth@xxxxxxxxx>
To: stds-802-3-efm@ieee.org
cc: (David Law/GB/3Com)
Subject: RE: [EFM] Re: OAM Transport Proposal
Just a few comments below:
Thanks,
Brad
-----Original Message-----
From: Matt Squire [mailto:mattsquire@xxxxxxx]
Sent: Tuesday, April 23, 2002 10:29 PM
To: stds-802-3-efm@ieee.org
Subject: [EFM] Re: OAM Transport Proposal
Another attempt to address multiple questions at
one time.
1) MDIO slowing preamble down. The intent is that
the any
bit handling
of the preamble is done below the MDIO interface.
One of
the reasons,
for me anyway, to keep the use of preamble to
communicating
a few very
specific states was for this point exactly.
Trying to
communicate real
'data' would be slowed down by getting the data
from the
MDIO
interface. The assumption is that the RS is
enhanced to
hold a small
number of state variables which can be
communicated via the
preamble
without turning into management frames over MDIO.
BJB> Using the RS for the preamble will bypass the
need for
use of the MDIO. I just want to be sure that we do clarify
that "pervasive
access" does not mean instantaneous or high-speed access. I
believe David
Law's term "pervasive" means that the MAC, MAC Control and
RS all have the
same direct access to the MIBs rather than via MDIO. The
management entity
would have the same speed of access to the MAC Control MIB
data as it would
to the RS MIB data. Therefore, the only way the RS can be
more responsive
than MAC Control is if there are state machines in the RS to
handle OAMinP
without management intervention.
3) Null/Dummy frames screwing up MIBS. Yes
semantics of the
undersized
frames variable will have to change to say
something like
"except for
null/dummy frames which are counted by ...". But
I think
things can be
defined in a way thats backward compatible. This,
along with
only using
those frames when the other side supports it,
should have
the effect of
MIB compatibility.
BJB> I get the feeling that there are a lot of
people that
would rather live without this feature.
4) Clauses effected. We did a preliminary
examination of
the clauses
that needed to be addressed by the proposal. The
following
is the list
as I see it.
- Clause 30 (Management). New MIB objects,
enhanced
locally and also
enhanced to include peer info.
- Clause 31 (MAC Control). Add OAM section,
fraem
formats, protocol
operation, bla bla bla
- Annex 43B. Add OAM types to slow protocols
list, maybe
change slow
protocol definition, etc.
- Clauses 22 & 45. New PHY monitoring registers
for
things like RX
power, signal-to-noise ration, etc.
- Annex 30A & 30B. New OIDs for managed
objects.
- Clause (new). OAM preamble byte format, use,
description, etc.
- Clause 22 & 35 (RS/MII, RS/GMII) - Dummy/null
frame
generation,
inclusion of preamble transport capability.
The preamble specific changes are the latter two.
Please
point out if
we're missing some clause changes somewhere. This
list does
not reflect
which clause changes are significant and which are
minor.
BJB> Do you have a list of clause editors to
perform these
modifications?
- Matt