Re: [EFM] [EFM-OAM] OAM Transport Proposal
The simplest way to think about the OAM Baseline proposal is that frames
are used to transport large amounts of data (many bytes) associated with
statistics, trace, identifiers, etc. Such transport is non-critical and
does not require large bandwidth which penalizes user bandwidth. The
preamble, or an 8-byte message during IPG which has the same format as
an OAM preamble, is used to transport several bits of critical
information such as faults and alarms. The preamble mechanism is
proposed because is relatively PHY independent, yet very intimate with
the PHY. From my perspective, it's one effective solution employing two
Note that the preamble mechanism provides an elegant solution for
critical link management of non MAC based optical termination units.
Sergiu Rotenstein wrote:
> I assume that Hiroshi already prepared part of the list of changes, as the
> original promoter of the method.
> But, beyond the changes, keep in mind that the new proposal includes the
> case of Preamble as an addition to frames based management. This means
> that we will have these changes anyway, proposed as additions to the MAC.
> What can be added to the proposal is a very simple mechanism that will allow
> auto-sense of preamble only.
> One simple way is to send upon link up a limited number of preamble messages
> (maybe ping). If the other side does not respond that means that does not
> support the method - or is down with the link active. In this case the
> regular operation is resumed. This will generate a minimum number of link
> errors and just upon link up (anyway an instable moment).
> This is one way. But the main issue is that we should support the link
> management of non MAC based optical termination units.
> Sergiu Rotenstein
> >>-----Original Message-----
> >>From: Booth, Bradley [mailto:bradley.booth@xxxxxxxxx]
> >>Sent: Tuesday, April 23, 2002 5:08 PM
> >>To: Sergiu Rotenstein; 'email@example.com'
> >>Subject: RE: [EFM] [EFM-OAM] OAM Transport Proposal
> >>I assume that an 802.3 repeater would be similar in concept to this
> >>converter you mention. For that, I can understand that a MAC
> >>level OAM may
> >>not be sufficient to provide the link/PHY level OAM that
> >>would be required.
> >>As much as OAM in preamble may solve the problem, I am still
> >>concerned about
> >>the changes required to 802.3 to provide this capability. I
> >>think that it
> >>would be great if an OAM in preamble supporter could compile
> >>a list of the
> >>changes required to existing clauses to add this feature.
> >>I just want the task force and working group to be
> >>well-informed about what
> >>we're signing up to do.