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RE: [EFM] Re: OAM - To side-band or not to side-band


Sorry, I'm trying to stay quiet on this thread but, obviously, am not
succeeding. I don't mean to sound rude but, if you're going to lecture the
chair of 802.1, you ought to get your 802.1 terminology (and facts maybe?)
right first. I'd suggest you read some of the 802.1 documents (start perhaps
with the "IEEE 802 overview and architecture" standard) and try explaining
your point of view about what is and is not a "bridge" or "repeater" in that

When you write "can not get access" I think perhaps you are describing a
particular product implementation as opposed to the entity defined by the
standards: it is perfectly allowed by IEEE 802 standards to place "end
station" functionality into the same sheet metal enclosure as any other type
of standard entity (802 standards do not, as far as I know, make any
statements at all about this). Whether or not products implement such an
"end station" function is purely a product/market decision, it is not a
valid technical argument for or against particular management channels in a

Andrew Smith

-----Original Message-----
[]On Behalf Of Roy Bynum
Sent: Wednesday, September 26, 2001 3:37 PM
To: Tony Jeffree; geoff Thompson
Cc: stds-802-3-efm
Subject: [EFM] Re: OAM - To side-band or not to side-band


Again, I think you may not be understanding what I am talking about.

Actually, according to Geoff Thompson, there is no such thing as a "full
duplex repeater".  A hub is not a repeater, it is a half duplex bridge.  A
switch is a full duplex "bridge".  Both have 802.1 functionality.

What I am referring does not have any 802.1 or 802.2 functionality.  It has
no visibility into the revenue data traffic stream.  It can not get access
to the revenue traffic data stream to put upper level application
management traffic such as SNMP into the revenue traffic data stream in
either direction.

Thank you,
Roy Bynum

At 07:47 PM 9/26/01 +0100, Tony Jeffree wrote:
>Roy -
>Managed Ethernet repeaters (more commonly known as hubs these days) have
>been around for some while, and they use MAC frames to carry their (SNMP)
>management exchanges. I would therefore hesitate to use that particular
>argument either for or against the use of a side-band for OAM.
>Having said that, in networks with repeaters there may be distinct
>advantages in *not* using such a side-band for OAM - for example, where it
>is the device the other side of the repeater that you want to manage.
>Unless, of course, you start putting some form of addressing into this
>PHY-based side channel, which rapidly starts to look like you're
>replicating MAC functionality in the PHY, which begins to look like a
>waste of time & effort.
>As to T1 and T3, there's no doubt that some of the EFM participants
>(myself for one) are not intimately acquainted with the management
>entrails of these technologies, and with the thinking behind why they are
>that way. I'm sure that some of that information may be useful in
>informing what we do in EFM.  However, I'm equally sure that re-inventing
>T1 or T3, giving it a bit-rate that is a power of 10, & then badging it
>"Ethernet", would be a total waste of our time.  After all, if you
>continue to do what you have always done, you inevitably end up with what
>you have always had.
>At 11:31 26/09/2001 -0500, Roy Bynum wrote:
>>There are a lot of other reasons to have the OAM ou-of-band to the MAC
>>traffic, such as being able to support OAM on an intelligent
>>"transparent" full duplex repeater in the future.  When this group took
>>on the task of adding subscription network support for edge access
>>infrastructure into Ethernet, they took on applying most all of the
>>functionality that is being used today.  There is a long history of why
>>the functionality for these types of services is what it is.  How many of
>>the EFM Task Force people have looked at how the OAM overhead of T1 or T3
>>framing works today?  How many of the EFM Task Force people have looked
>>into why the OAM overhead of T1 or T3 framing works the way that it does?