Re: Issues in mapping Ethernet signal to SONET
Ben, Dave,
Reading this note, it seems that there is some conflict between what WAN PHY
proposal IS on the table and what ISN'T on the table. Can you please clarify the
situation and list the ACTIVE WAN PHY proposals?
One WAN PHY proposal that I know is on the active list is Mr. Howard Frazier's
UniPHY proposal:
http://grouper.ieee.org/groups/802/3/ae/public/mar00/frazier_1_0300.pdf
Dave,
This is he first time I've heard the PCS1/PCS2 terminology. We previously had
the same problem with the 8B/10B code proposed for Hari and solved it by
proposing the optional XAUI/XGXS interface and associated sublayers. I don't
believe that there's any proposal for the LAN, WAN or UniPHY that requires two
PCS sublayers. All PCS functions can be described in a single PCS sublayer.
What is the specific reason for introducing this new terminology and how does it
appear in the layer model? If you draw a picture of it, please use the model
from Mr. Brad Booth's "IEEE P802.3ae Document Structure" presentation:
http://grouper.ieee.org/groups/802/3/ae/public/mar00/booth_1_0300.pdf
Best Regards,
Rich
--
> David Martin wrote:
>
> Ben,
>
> A correction to your delineation explanation below. It should state that after
> the Ethernet data stream is extracted from the SONET payload by the PMA (PCS2
> in the new terminology), the receive PCS (PCS1 in the new terminology) gains
> synchronization by searching for any header (data or idle frame) with a valid
> HEC. It maintains synchronization by using the validated length value to point
> to the next frame, which again it confirms OK by verifying that header has
> a valid HEC, and so on.
>
> I see that Paul Bottorff has clarified in a later e-mail that the
> <length><type><HEC> proposal continues to be our position for the WAN PHY.
>
> ...Dave
>
> David W. Martin
> Nortel Networks
> +1 613 765-2901
> +1 613 763-2388 (fax)
> dwmartin@nortelnetworks.com
>
> ========================
>
> -----Original Message-----
> From: Brown, Ben [NHBED:DS48:EXCH]
> Sent: Tuesday, April 11, 2000 6:02 PM
> To: stds-802-3-hssg@majordomo.ieee.org
> Subject: Re: Issues in mapping Ethernet signal to SONET
>
> Tripathi,
>
> I'll let someone else respond to your clock tolerance
> questions. As to why is the Length field inserted into the
> preamble, this is for packet delineation. The proposal
> put forth by Paul Bottorff, et al:
>
> http://grouper.ieee.org/groups/802/3/10G_study/public/jan00/figueira_1_0100.pdf
>
> used a DATA header, consisting of Length, Type and HEC
> fields in place of the preamble, to delineate the packets.
> It also replaced IDLEs with similar IDLE headers, using a
> Length value of 0. After the ethernet data stream is extracted
> from the SONET payload by the PMA, the receive PCS gains
> synchronization by searching for IDLE headers with a valid
> HEC then maintains synchronization by using the Length field
> to look for the start of the next header (IDLE or DATA).
>
> I don't believe this particular PCS proposal is still on the
> table. Though Nortel still feels strongly about using a WIS
> of sorts to put the ethernet data stream into a SONET payload,
> I believe Nortel has succumbed to the pressures of requesting
> a length value from the MAC (or including the buffering and
> latency within the PCS to count bytes) and is now in support
> of Lucent's SLP proposal.
>
> Hope this helps,
> Ben
>
> Devendra Tripathi wrote:
> >
> > Hi,
> > Could some one illustrate (or give pointer to existing document) on
> various
> > issues
> > in mapping an Ethernet signal
> > @9.584640 (+-100ppm) to OC-192 stream. As Paul has already pointed out,
>
> > the muxer, should be able to absorb 320 ppm tolerance. Basically I
> would like
> > to understand the reasoning for Length insertion in preamble (which
> makes the
> > scheme somewhat unpleasant). The basic
> > OAM&P function like remote fault and break link are already being
> talked
> > about as part of the control code (as part of Ethernet stream).
> > Thanks in advance,
> >
> > Best Regards,
> >
> > Devendra Tripathi
> > Vitesse Semiconductor Corporation
> > 3100 De La Cruz Boulevard
> > Santa Clara, CA 95054
> > Phone: (408) 986-4380 Ext 103
> > Fax: (408) 986-6050
> > ********************************************************************
> >
> > Web: http://www.vitesse.com
>
> --
> -----------------------------------------
> Benjamin Brown
> Router Products Division
> Nortel Networks
> 1 Bedford Farms,
> Kilton Road
> Bedford, NH 03110
> 603-629-3027 - Work
> 603-624-4382 - Fax
> 603-798-4115 - Home
> bebrown@nortelnetworks.com
> -----------------------------------------
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