Re: 64/66 control code mapping
Rich,
I am not attempting to deminish the view of the elegant nature of the 8B10B
encoding scheme. I think that Hari is a very valuable technology. I am
questioning that it applies as a solution to all problems.
Thank you,
Roy Bynum
----- Original Message -----
From: Rich Taborek <rtaborek@xxxxxxxxxxx>
To: HSSG <stds-802-3-hssg@xxxxxxxx>
Sent: Monday, March 13, 2000 1:11 PM
Subject: Re: 64/66 control code mapping
>
> Roy,
>
> Architecturally, the proposed layering of 10 GbE requires a MAC and
> Reconciliation sublayer and a PCS. It requires neither a XGMII nor
XAUI/XGXS and
> both these interfaces are proposed as optional interfaces. The
Reconciliation
> sublayer maps data and control signals to PLS service primitives defined
in
> Clause 6 of the 802.3 standard.
>
> In the case that the PCS is 64B/66B in support of a Serial PHY type, I see
no
> requirement for 8B/10B encoding/decoding to be performed. The fact that
both the
> XGMII and 64B/66B support special codes to simplify synchronization,
> delineation, error checking, parallel lane deskew, jitter control, clock
> tolerance compensation, etc. and that these codes are similar to those
used by
> 8B/10B are a credit to the elegant and timeless nature of the 8B/10B
> transmission code developed by Widmer, et. al.
>
> Best Regards,
> Rich
>
> --
>
> Roy Bynum wrote:
> >
> > Rich,
> >
> > It was my impression that I got from the 64B/66B presentations, that an
> > 8B10B precoding was a requirement for the 64B/66B in order for detection
of
> > errored codes. In every presentation that I have seen so far, 8B10B
> > precoding was included. This makes XAUI not optionional, but a
requirement
> > for the 64B/66B encoder, regardless of whether the XAUI is optional in
the
> > standard. So, unlike other proposals, a unifed PHY that uses 64B/66B
has
> > XAUI as a requirement, or at least some other 8B10B precoder is
required.
> >
> > Thank you,
> > Roy Bynum
> >
> > ----- Original Message -----
> > From: Rich Taborek <rtaborek@xxxxxxxxxxx>
> > To: HSSG <stds-802-3-hssg@xxxxxxxx>
> > Sent: Monday, March 13, 2000 5:40 AM
> > Subject: Re: 64/66 control code mapping
> >
> > >
> > > Ben,
> > >
> > > The proposed XGMII is an encoded interface which can be directly
mapped to
> > > either XAUI/XGXS and/or 64B/66B. The "and/or" indicates that XAUI/XGXS
> > > need not be present.
> > >
> > > I believe that you are correct in stating that the spec should provide
the
> > > proper translation between XGMII codes and 64B/66B codes regardless of
> > > whether XAUI/XGXS is present. The PCS is the specific part of the spec
> > > documenting this translation.
> > >
> > > Therefore, if 64B/66B coding is accepted as the Serial PHY code of
choice,
> > > the PCS should specify the translation of information between the
XGMII
> > > and PMA and operate correctly in the presence or absence of XAUI/XGXS.
> > >
> > > Best Regards,
> > > Rich
> > >
> > > --
> > >
> > > "Benjamin J. Brown" wrote:
> > > >
> > > > Rick Walker,
> > > >
> > > > I've been looking at your 64b/66b presentation and, in
> > > > particular, looking at your control code mapping. The
> > > > 7-bit line code is specific to encodings from the 8b10b
> > > > XAUI interface. This is an optional interface and may
> > > > not exist between all MAC and PCS layers. When the XAUI
> > > > doesn't exist, what 7-bit line codes should be used?
> > > >
> > > > Given the protocol stack shown by Brad Booth, I would
> > > > expect that this PCS layer be specified to an XGMII
> > > > and not to an XAUI. Implementations may choose to short-
> > > > cut the conversion from XAUI to XGMII to 64b/66b but
> > > > the specification should assume it communicates to the
> > > > XGMII.
> > > >
> > > > Thanks,
> > > > Ben Brown
> > > >
> > > > --
> > > > -----------------------------------------
> > > > Benjamin Brown
> > > > Router Products Division
> > > > Nortel Networks
> > > > 1 Bedford Farms,
> > > > Kilton Road
> > > > Bedford, NH 03110
> > > > 603-629-3027 - Work
> > > > 603-629-3070 - Fax
> > > > 603-798-4115 - Home
> > > > bebrown@xxxxxxxxxxxxxxxxxx
> > > > -----------------------------------------
>
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