RE: PHYs with 10.000 and 9.584640

["Booth, Brad" <bbooth@xxxxxxxxxx>]

Title: RE: PHYs with 10.000 and 9.584640

Jaime,

In essence, this is placing the burden on the subset of PHY implementers.  I'm not advocating a PHY that works at two rates, I'm advocating a MAC/PLS that works at one rate - 10Gb/s.  The PHY's would map the MAC/PLS data rate to their corresponding data rate, and in this architecture, only the WAN PHY would have to do something special to decrease the data rate to 9.58464 Gb/s.  Maybe a new PHY sublayer is necessary to perform the data rate mapping.

I don't think we require two separate PARs because of the differences in a LAN PHY compared to a WAN PHY.  What I believe is required is to isolate where the differences between these two types of networks are, and I believe that can be done by having a LAN PHY and a WAN PHY.  To the system designer, the implementation becomes easier if they can pick a 10GbE MAC and plug it to a PHY of their choosing.  The PLS service interfaces are the same and the operations inside the MACs are the same, only the PHYs are different: one is LAN capable, and the other is WAN capable.  Keeping this all in one PAR can help to guarantee this interoperability of MAC, PLS and PHY.

Thanks,
Brad

Brad Booth
bbooth@xxxxxxxxxx
Level One Communications, Austin Design Center
(512) 407-2135 office
(512) 589-4438 cellular

-----Original Message-----
From:   Jaime Kardontchik [SMTP:kardontchik.jaime@xxxxxxxxxxx]
Sent:   Thursday, July 22, 1999 1:03 PM
To:     stds-802-3-hssg@xxxxxxxx
Subject:        PHYs with 10.000 and 9.584640




Hello Brad and other 10G'ers:

This looks to me like throwing the problem to the subset of PHY
implementers,
since the HSSG (read subset of marketing, system and MAC engineers) does

not know how to solve the impasse and get the 75 % approval to either
10.000 or 9.584640 Gbps.

Are these PHYs going to be capable of sending/receiving both at
10.000 and 9.584640 Gbps ? This would appear to contradict the
accepted idea in the HSSG that the future standard should be
either 10 or 9.584640 (exclusive, but not both).

Are we going to define separate PHYs, one for 10.000 and another
for 9.584640 Gbps ?  Then perhaps it would be better to define two
separate PARs and working groups, since behind these two different
clock rates are hidden many additional differences (it is not just
choosing between short-wave or long-wave laser PHYs).

Jaime

Jaime E. Kardontchik
Micro Linear
San Jose, CA 95131
email: kardontchik.jaime@xxxxxxxxxxx

>
> -----Original Message-----
>From: Booth, Brad [mailto:bbooth@xxxxxxxxxx]
>Sent: Wednesday, July 21, 1999 9:22 PM
>To: HSSG
>Subject: RE: 9.584640
>
>
>
>I really liked the proposal that Kevin Daines put on the overhead.  One
of
>the reasons that I liked the proposal is that it matched what I
pictured in
>my mind. :-)  But there were other technical reasons why I liked it.
The
>proposal for those that missed it was to leave the MAC/PLS data rate at
10.0
>Gb/s, but to have the PHYs determine what data rate was required.  In
the
>case of a LAN PHY, the data rate would be 10.0 Gb/s... a direct match
to the
>MAC/PLS data rate.  In the case of a WAN (or OC-192) PHY, the data rate

>would be 9.58464 Gb/s and the PHY would obtain that data rate by either
some
>form of flow control or buffering scheme.
>
>I like this because it allows the LAN architectures to remain cost
effective
>while offering the ability to easily concentrate links (i.e. ten 1 GbE
links
>map nicely into one 10 GbE link).  This architecture puts a bit of a
cost
>burden on the WAN PHY, but I think that this still results in a cost
>effective solution for OC-192.  The WAN solution may not be as low cost
as
>the LAN solution, but show me a Gb/s WAN solution today that is as cost

>effective as a Gb/s LAN solution.
>
>The other part that I like is that the only real difference between the
WAN
>and LAN solutions in Kevin's proposal is the PHY.  Everything above the
PHY
>(including interface to PHY) remains relatively unchanged.  Yes, it's
all
>going much faster, but that's an implementation issue, not a standards
>issue.  At least that's my impression. :-)
>
>Just my 2 cents worth,
>Brad
>
>Brad Booth
>Level One Communications, Austin Design Center
>(512) 407-2135 work
>(512) 589-4438 cell