RE: Link Status encodings
Boaz,
I think that the transmit side works independently
except that it sends some report about the fault in
the form of RF.
James
--- Boaz Shahar <boazs@xxxxxxxxxxxx> wrote:
>
> A question:
> When the DTE XGXS enters IDLE mode: Is it happens
> only after recognizing a
> link fault condition? (3 times RF) or immediately
> after the first one? And
> in this state: If the RS continue to transmit data,
> the DTE XGXS stays in
> IDLE or transmits the data and only changes the idle
> pattern so that it
> contains POS?
> Boaz
>
> > -----Original Message-----
> > From: Rich Taborek [mailto:rtaborek@xxxxxxxxxxxxx]
> > Sent: Friday, November 24, 2000 12:24 AM
> > To: HSSG; Rhett Brikovskis
> > Subject: Re: Link Status encodings
> >
> >
> >
> > Pat,
> >
> > Rhett Brikovskis and I have modified Clause 48
> Receive and Transmit
> > state machines, which are also used by Clause 47
> XAUI/XGXS, to support
> > Link Status reporting. One of the true advantages
> of combining all of
> > the 10GBASE-X and XAUI/XGXS receive and transmit
> protocol in Clause 48
> > is the inherent simplification realized when
> multiple instances (of
> > Clause 48) are employed in a link. This is exactly
> the situation
> > applicable to your example which I'll
> re-illustrate:
> >
> > Node A
> > RS (XGMII) DTE XGXS - XAUI - PHY XGXS - 64b/66b
> PCS >>>>>>>
> >
> V
> > Node B
> V
> > RS (XGMII) DTE XGXS - XAUI - PHY XGXS - 64b/66b
> PCS <<<<<<<
> >
> > Using your example of the Node A Reconciliation
> sublayer (RS) sending
> > Remote Fault (RF), this is what proposed D2.0
> Clause 48 state machines
> > will do:
> >
> > 1) Since Link Fault and Packet transmission is
> mutually exclusive per
> > taborek_2_1100.pdf, the Node A RS always
> alternates RF with Idle;
> >
> > 2) The RF/Idle sequence is passed to the Node A
> DTE XGXS
> > which utilizes
> > a Clause 48 Transmit process. The Transmit process
> enters
> > Idle mode, if
> > not already in Idle mode, and forwards the RF as
> normal Data over its
> > PMA and on to its XAUI. Note that a link fault
> condition has not been
> > recognized by the Transmit process at this point;
> >
> > 3) After the detection of three RF indications
> (columns of
> > /9C,1/00,0/00,0/02,0/ across the XGMII from the
> RS), the Clause 48
> > Transmit process in the Node A DTE XGXS recognizes
> a link_fault
> > condition and alters its output to a Pulse
> sequence. The
> > Pulse sequence
> > is identical to the Idle Sequence except that the
> Pulse ordered-set,
> > ||P|| follows every ||A||. The primary distinction
> of the
> > Pulse protocol
> > is to keep EMI low while reliably and continuously
>
> > transporting a single
> > message easily distinguishable from Idle, in this
> case, RF. The Pulse
> > sequence is forwarded by the PCS Transmit process
> over its associated
> > PMA and on to its XAUI;
> >
> > 4) The Node A PHY XGXS utilizes a Clause 48 PMA,
> > Synchronization, Deskew
> > and Receive process. Assuming that the underlying
> XAUI,
> > associated PMA,
> > PCS Synchronization and PCS Deskew process is
> operational, the PCS
> > Receive process will recognize a link_fault
> condition after the
> > detection of three RF indications (columns of
> /K28.4/D0.0/D0.0/D2.0/
> > across the XAUI). Upon the recognition of a
> link_fault condition, the
> > PCS Receive process forwards an alternating
> sequence of Pulse and Idle
> > control columns to its PCS client. In this case,
> the client
> > of the Node
> > A PHY XGXS is the 64b/66b PCS;
> >
> > 5) Note that to this point, the Pulse sequences
> use to convey the RF
> > indication across the XGMII (or directly between
> the RS and
> > DTE XGXS in
> > the absence of an XGMII) and the Pulse sequences
> over XAUI are
> > different. The XGMII Pulse sequences over XAUI are
>
> > necessarily different
> > to minimize EMI over this typically extended
> interface. However, there
> > is no reason to differentiate or further
> complicate the Pulse sequence
> > protocol over all interfaces other than XAUI
> beyond that agreed to in
> > taborek_2_1100.pdf. Specifically, slide 12 says:
> "RS Alternates Signal
> > With Idle Continuously". The same Pulse signaling
> is applicable to the
> > XGMII, across 64b/66b, XSBI, SUPI and the WIS.
> We've been through this
> > exercise once before with respect to passing XAUI
> specific
> > codes such as
> > /A/, /K/ and /R/ over the XGMII. For exactly the
> same reasons, and for
> > reasons of keeping the Link Status reporting
> protocol throughout all
> > elements of a P802.3ae link, I strongly suggest
> that all P802.3ae
> > sublayers and interfaces other than those
> specified in Clause
> > 48 signal
> > link fault conditions by continuously alternating
> Pulse with Idle;
> >
> > 6) Steps 2 through 4 are equivalently applicable
> to all sublayers and
> > interfaces in Node B. Note that the direction of
> the Clause
> > 48 processes
> > are opposite to that in Node A.
> >
> > The protocol description should alleviate any
> concerns with non
> > deterministic RF indication spacing outlined in
> your previous note on
> > this thread.
> >
> > P.S. Clause 48 ||A|| spacing is not ambiguous and
> is specified in D1.1
> > page 148, line 11 as:
> > e) ||A|| spacing is randomized in the range of 17
> columns
> > minimum and 32
> > columns maximum. A 17 column minimum ||A|| spacing
> provides an 85-bit
> > deskew capability;
> >
> > Best Regards,
> > Rich
> >
> > --
> >
> > pat_thaler@xxxxxxxxxxx wrote:
> > >
> > > Ben,
> > >
> > > By my calculations, at the receiving RS there
> can be up to
> > 64 columns
> > > between ordered sets. Take the instance where an
> RS is sending RF.
> > >
> > > The signal can go through
> > > Node A
> > > RS - DTE XAUI - PHY XAUI - PCS >>>>>>>
> > > V
> > > Node B V
> > > RS - DTE XAUI - PHY XAUI - PCS <<<<<<<
> > >
> > > At Node A's RS, it will start out being
> transmitted every
> > other column.
> > > Node A's DTE XAUI will transmit it after each A
> because it
>
=== message truncated ===
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