Re: 64/66 control code mapping
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@nSerial.com>
To: HSSG <stds-802-3-hssg@ieee.org>
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@nortelnetworks.com
> > -----------------------------------------
>
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