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RE: [EFM] Re: OAM Transport Proposal

Hi Martin,

I hope Matt doesn't mind me answering this one.

Clause 41 is the 1Gb/s Repeater specification [Clause 41 - Repeater for 1000
Mb/s baseband networks]. Repeaters are also specified for 100Mb/s [Clause 27 -
Repeater for 100 Mb/s baseband networks ] and 10Mb/s [ Clause 9 - Repeater unit
for 10 Mb/s baseband networks ] operation. As a point of clarification, IEEE Std
802.3 specifies a 'Repeater' which I would define as follows [copied from the
10Gb/s terminology document].

802.3 Repeater

a) 10, 100, 1000 single speed.
b) Half-duplex, CSMA/CD only (no full-duplex).
c) Shared access to a single channel.
d) Bit store and forward for clock tolerance differences.
e) Fractional packet latency.

While I agree that the above is what is being referred to as a 'half-duplex
repeater' below, I do not believe that term is used anywhere within IEEE Std

  David Law

"Martin Nuss" <nuss@xxxxxxxxxxxxxxxxxxxxx> on 25/04/2002 12:39:44

Sent by:  "Martin Nuss" <nuss@xxxxxxxxxxxxxxxxxxxxx>

cc:    (David Law/GB/3Com)
Subject:  RE: [EFM] Re: OAM Transport Proposal


Which of these are covered by clause 41?


-----Original Message-----
From: Matt Squire [mailto:mattsquire@xxxxxxx]
Sent: Wednesday, April 24, 2002 5:54 PM
Subject: RE: [EFM] Re: OAM Transport Proposal

We've had many threads on repeaters, media converters, regenerators, and
the like throughout the evolution of this work.  The following are my
recollections as reported by others (Geoff, Tony, etc.).  Pls correct
anything I misrepresent.

1) 802.3 defines half-duplex repeaters.
2) 802.3 does not define full-duplex repeaters.
3) What some people commonly refer to as full duplex repeaters are
actually 2-port MAC frame forwarders (802.1D relays?).
4) 802.3 does not define optical regenerators (ie protocol agnostic
signal regeneration).
5) 802.3 does not define media converters.

Since using the preamble to carry signaling is intended as a full-duplex
function only, I short-cut to the conclusion that preamble has no
applicability to any repeater, regenerator, or media converter as
defined by 802.3.  Before we could figure out how to address this
full-duplex repeater function that does not exist in 802.3, it would
have to be properly defined.  Thats all I was getting at.

People are concerned, people are thinking about it, but it has been
difficult to address because of the terminology confusion and our

- Matt

>Hi Matt and all,
>I will address only the issues related to 5) Regenerators and
>First of all I want to assume that we consider all the 802.3
>including 100 Mbps and GbE.
>802,3 defines the above entities. Look at 27. Repeater for 100
>Mbps baseband
>The devices that we address are two port full duplex repeaters.
>Also 802.3ab makes extensive references to repeater implementations.
>And again, the moment that we defined any preamble based
>capability - see
>page 9
>of the baseline presentation - we decided to make the
>appropraite changes
>for preamble
>I also had some questions, regarding packet based functionality.
>This functionality I assume is not fully contained in the new
>MAC (like the
>packet based
>flow control functionality). It requires an external processing unit
>(CPU+MAC, HW, or whatever).
>What is the level of service in the case of a busy link (even
>due to a broadcast
>storm, etc.)? Do we lose the management capacity for some time?
>Wouldn't an out-of-band mechanism (like preamble) be valuable
>in order to
>provide even the
>basic management information as defined in the suzuki proposal?
>I still think that the compromise should be a functional
>compromise, that
>provide the
>best of the two worlds meaning that the capabilities
>negotiations should
>include four
>options, and should be done also at the lowest level...