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Rich, Pat, on a slightly different tack:
if a PCS encounters a FIFO under/over run condition, but is still frame and or column synchronized, it should still post a LF to the RS. The condition I'm thinking of is handling a jumbo packet or a jabbering station. The question is how should the PCS come out of the under/over run condition?
Should it:
a. wait for MDIO intervention to clear it's link fault condition?
b. wait for idles on the in-bound path?
c. something else in clause 48 or 49 I haven't read yet.
Regards,
Shawn
> -----Original Message-----
> From: Rich Taborek [mailto:rtaborek@xxxxxxxxxxxxx]
> Sent: Monday, December 24, 2001 3:01 PM
> To: HSSG (E-mail)
> Subject: Re: [802.3ae] Link Fault Signalling
>
>
>
> Gal,
>
> You are correct. Fault recognition does not require the usage of LF/RF
> sequences.
>
> Happy Holidays,
> Rich
>
> --
>
> "Ofek, Gal" wrote:
> >
> > Pat,
> >
> > re:"The RS does not poll the MDIO"
> > Of course, you're right!(formally...)
> >
> > re:"but if the PMD/PMA isn't getting good signal, the PCS
> will not be
> > able to get lock to the signal from the PMD/PMA"
> >
> > Still, in general, there will be cases in which a fault
> will be indicated
> > through the link status bit (1.1.7) and not
> > through the LF/RF sequences, right?
> >
> > Thanks
> > Happy&Merry Holidays
> > Gal Ofek
> > Intel Communications Group - ISRAEL(Omer)
> > Email: gal.ofek@xxxxxxxxx
> >
> > -----Original Message-----
> > From: THALER,PAT (A-Roseville,ex1) [mailto:pat_thaler@xxxxxxxxxxx]
> > Sent: Thursday, December 20, 2001 8:54 PM
> > To: rtaborek@xxxxxxxxxxxxx; HSSG (E-mail)
> > Subject: RE: [802.3ae] Link Fault Signalling
> >
> > Rich,
> >
> > I want to clarify something. The local fault bit in a
> device is only set
> > when the device detects a problem; for example low power or
> inability to
> > acquire sync. It is not set in response to receiving a
> Local Fault signal on
> > its input.
> >
> > Gal,
> >
> > The RS does not poll the MDIO. The RS is not required or
> expected to have a
> > connection to the MDIO. If the receive side of the link
> isn't working, the
> > RS should receive LF. True the PMD/PMA doesn't send LF when
> it detects a
> > fault, but if the PMD/PMA isn't getting good signal, the
> PCS will not be
> > able to get lock to the signal from the PMD/PMA.
> >
> > The purpose of the MDIO is to allow the local management to
> determine PHY
> > layer status and localize problems. The MDIO is not
> designed to support
> > multiple masters so it would be awkward to have the
> management agent and the
> > RS both poll the MDIO.
> >
> > Regards,
> > Pat
> >
> > -----Original Message-----
> > From: Rich Taborek [mailto:rtaborek@xxxxxxxxxxxxx]
> > Sent: Wednesday, December 19, 2001 11:12 PM
> > To: HSSG (E-mail)
> > Subject: Re: [802.3ae] Link Fault Signalling
> >
> > Gal,
> >
> > Sorry about the late reply. Sometimes my email gets way backed up.
> >
> > Status register bit 1.1.7 is defined as Local Fault. This bit is set
> > when a local fault condition exists. The local fault
> condition may have
> > been signaled via LF/RF signaling but this is only one
> possibility. The
> > others include LF detection at the receiver not via LF/RF
> signaling and
> > LF detection inboard of the receiver.
> >
> > Happy Holidays,
> > Rich
> >
> > --
> >
> > > -----Original Message-----
> > > From: Ofek, Gal [mailto:gal.ofek@xxxxxxxxx]
> > > Sent: Monday, December 10, 2001 9:48 AM
> > > To: 'rtaborek@xxxxxxxxxxxxx'
> > > Cc: HSSG (E-mail)
> > > Subject: RE: [802.3ae] Link Fault Signalling
> > >
> > > Rich,
> > >
> > > Thanks but I would like one more clarification:
> > > Is the following true:
> > > it is not enough that the RS
> > > will relay totally on the Local/Remote fault signaling to
> report for
> > > link fault. It should also poll the link status bit (bit 1.1.7)
> > > in order to get a complete indication about the link status.
> > >
> > > Yes?
> > >
> > > Thanks
> > > Gal
> > >
> > > -----Original Message-----
> > > From: Rich Taborek [mailto:rtaborek@xxxxxxxxxxxxx]
> > > Sent: Sunday, December 09, 2001 11:18 PM
> > > Cc: HSSG (E-mail)
> > > Subject: Re: [802.3ae] Link Fault Signalling
> > >
> > > Gal,
> > >
> > > No. I was creating a distinction between the stages of a
> link fault and
> > > the reporting of the fault. Here's a more complete
> distinction in the
> > > life of a fault. and LF
> > >
> > > a) the existence of a link fault condition;
> > > b) the recognition and of the link fault condition (note
> that some link
> > > fault conditions may not be detected and recognized,
> preventing their
> > > reporting by a local fault message);
> > > c) the reporting of a recognized link fault condition via
> a local fault
> > > message (note that this requires a "fault message
> reporting facility"
> > > such as an 8B/10B PCS or equivalent);
> > >
> > > In most cases, a link fault condition is recognized at
> the DTE through
> > > either reception of a local fault message or detection of
> a link fault
> > > condition. An example of a link fault condition which may escape
> > > detection and recognition by any link element including
> the DTE's is a
> > > receiver failure where crosstalk from the associated
> transmitter covers
> > > up failure condition at the receiver.
> > >
> > > I hope this explanation helps,
> > > Best Regards,
> > > Rich
> > >
> > > --
> > >
> > > "Ofek, Gal" wrote:
> > > >
> > > > Do you mean that a situation in which a link is down
> (fault condition)
> > > > but no local fault will be generated is allowed?
> > > >
> > > > Thanks
> > > > Gal
> > > >
> > > > -----Original Message-----
> > > > From: Rich Taborek [mailto:rtaborek@xxxxxxxxxxxxx]
> > > > Sent: Sunday, December 09, 2001 7:32 AM
> > > > Cc: HSSG (E-mail)
> > > > Subject: Re: [802.3ae] Link Fault Signalling
> > > >
> > > > Chuck,
> > > >
> > > > I'll address two issues here. One is yours, the other
> is other is
> > > > related to kicking off Fault Messages.
> > > >
> > > > 1) Unidirectional link behavior is not supported
> because it does not fit
> > > > the scope of Ethernet objectives. Specifically, a
> full-duplex link
> > > > cannot be reinitialized properly when a fault occurs if
> no feedback
> > > > mechanism is provided to insure that both link
> directions participate in
> > > > initialization. I understand your point about this mode
> of operation
> > > > being about the scope of 802.3ae (and 802.3 in
> general). However, even
> > > > protocols like SONET provide other mechanisms, such as
> DCC channels to
> > > > accomplish the same thing. The problem is that the DCC
> channel is only
> > > > the feedback mechanism and provides no help in
> resolving the actual
> > > > fault, which is likely to require manual intervention
> upon fault if the
> > > > link is properly designed.
> > > >
> > > > 10GE employs LF/RF protocol as a means of quickly
> determining the
> > > > operational state of a link. If the link is not operational, an
> > > > alternate link should be switched in.
> > > >
> > > > 2) Local Fault Ordered Sets are only generated upon
> detection of a link
> > > > fault condition when a capability exists that can
> generate Local Fault
> > > > Ordered Sets. Some sublayers and link elements such as
> PMDs, retimers
> > > > and PMAs may have the capability of detecting link
> fault conditions but
> > > > not of generating Local Fault Ordered Sets. In this
> case, no error may
> > > > be reported at all or an error may be reported through
> an alternate
> > > > means. IEEE 802.3ae has no requirement to generate
> local fault ordered
> > > > sets upon detection of a link fault condition.
> > > >
> > > > Best Regards,
> > > > Rich
> > > >
> > > > --
> > > >
> > > > Chuck Harrison wrote:
> > > > >
> > > > > Ben, all --
> > > > >
> > > > > Ben Brown wrote:
> > > > > >
> > > > > > > > [BC] Thanks for the replies. My understanding
> now is as follows:
> > > > > > > >
> > > > > > > > 1. If a fault is detected on the receive path,
> at the PMD or
> > > > > > > > the PMA, Local Fault Ordered Sets (LFOS)
> will be transmitted
> > > > > > > > by the PCS to the RS. Consequently, the RS
> will send Remote
> > > > > > > > Fault Ordered Sets (RFOS) to the PCS.
> > > > > >
> > > > > > [BB] This is correct.
> > > > >
> > > > > Agree 100%, this is the standard behavior and *must*
> be supported.
> > > > >
> > > > > However, I recommend that silicon manufacturers implementing
> > > > > RS consider whether they also wish to support a non-standard
> > > > > mode in which LF->RF reflection does *not*
> automatically occur.
> > > > > This would allow their products to work in application niches
> > > > > using a *unidirectional* optical link. (The transmit
> end always
> > > > > sees a receive LF, but goes on talking anyway.)
> > > > >
> > > > > I recognize this is outside the scope of 802.3ae, but some
> > > > > industry segments would value this capability.
> > > > >
> > > > > Cheers,
> > > > > Chuck Harrison
> > > > > Far Field Associates, LLC
> > > > > member, SMPTE DC28.1 Steering Committee on Digital Cinema
>
> ---------------------------------------------------------
> Richard Taborek Sr. Intel Corporation
> XAUI Sherpa Intel Communications Group
> 3101 Jay Street, Suite 110 Optical Strategic Marketing
> Santa Clara, CA 95054 Santa Clara Design Center
> 408-496-3423 JAY1-101
> Cell: 408-832-3957 mailto:rich.taborek@xxxxxxxxx
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>