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RE: [10GBASE-T] Clauses 22 and 45



Title: Message
Those are the questions to be answered.  I think there is a possibility of repeating what we did in 802.3ae.  One goal that we tried to shoot for was to have the register sets of Clause 22 and 45 look very similar, so that ties in with your idea of having the Clause 22 functionality move into Clause 45 as a xxBASE-T PCS.  There will be a need for 10GBASE-T registers in Clause 45 to have similar functionality to those found in Clause 22.  If 10GBASE-T uses the similar functionality and register set as that in Clause 22, mapped into Clause 45, then we should be able to use a xxBASE-T PCS status register that can indicate the PHYs abilities from 10, 100, 1G and 10G.  I think as we move forward devices will start to support Clause 45 MDIO (especially those designed for 10G or faster) but will still offer legacy support for older PHYs (migration path).  The key will be to enable the legacy xxBASE-T speeds built into 10GBASE-T PHYs to be accessed via one Clause 45 interface, without the need for a Clause 22 interface.  A sort of "service to humanity" thing. :-)
 
Thanks,
Brad
-----Original Message-----
From: pat_thaler@agilent.com [mailto:pat_thaler@agilent.com]
Sent: Tuesday, March 25, 2003 5:57 PM
To: Booth, Bradley; stds-802-3-10gbt@ieee.org
Subject: RE: [10GBASE-T] Clauses 22 and 45 (was EFM OAM...)

Brad,
 
(I changed the subject to better reflect the current topic)
 
That the point  of what I was suggesting. The size of the Clause 22 register area is pretty small. 10GBASE-T management would benefit from the larger space available with the Clause 45 register addressing. Also, as you point out, Clause 45 is probably the way of the future.
 
My point is that it isn't necessarily an either/or decision. For a 10/100/1000/10G Phy (or some subset of those speeds), one could use  Clause 22 registers to control the autonegotiation and, in the cases where the negotiation chooses one of PHYs currently covered by Clause 22, one would use the Clause 22 registers to manage the PHY. If the negotiation chooses 10GBASE-T, then one can use Clause 45 to manage its operation.
 
The alternative is to move all the Clause 22 functionality into registers in a Clause 45 device (xxBASE-T PCS?) so that everything could be managed through that register set.
 
Is it better to have two different register maps to access management information for a 1000BASE-T device depending on whether it is packaged with a 10GBASE-T device or not, or is it better to keep one register map per PHY type and have ICs supporting old and new PHY types support two forms of register addressing?
 
Pat
 
 -----Original Message-----
From: Booth, Bradley [mailto:bradley.booth@intel.com]
Sent: Tuesday, March 25, 2003 1:02 PM
To: stds-802-3-10gbt@ieee.org
Subject: RE: [10GBASE-T] EFM OAM...

Pat,
 
Another area to consider is that Clause 28 auto-negotiation is written to only support interaction with Clause 22 registers, yet Clause 45 is more likely to be used as Ethernet moves forward.  This is where 10GBASE-T may need to reflect the registers used by our previous BASE-T PHYs in the 10GBASE-T register set.  Or am I just making a mountain out of a fire ant hill?
 
Cheers,
Brad
-----Original Message-----
From: pat_thaler@agilent.com [mailto:pat_thaler@agilent.com]
Sent: Tuesday, March 25, 2003 2:31 PM
To: Booth, Bradley; stds-802-3-10gbt@ieee.org
Subject: RE: [10GBASE-T] EFM OAM...

Brad,
 
The clause 45 register addressing was constructed so that it didn't interfere with clause 22 register access. If 1000BASE-T devices can auto-negotiate, they could use clause 22 defined registers for addressing that auto-negotiation mechanism and use clause 45 registers for 10 Gig specific management. 
 
The only conflict one would have to resolve is in the electrical interface to the management registers. Clause 22 specifies higher voltage than Clause 45. Given current technology, one probably would want to use the Clause 45 electrical specification.
 
Regards,
Pat 
 
 -----Original Message-----
From: Booth, Bradley [mailto:bradley.booth@intel.com]
Sent: Monday, February 24, 2003 7:57 PM
To: stds-802-3-10gbt@ieee.org
Subject: RE: [10GBASE-T] EFM OAM...

Ahmet,
 
Valid points.  Some may argue that EFM OAM didn't exist when 1000BASE-T or 1000BASE-X were written, but that has not prevented EFM OAM from having some affect on 1000BASE-X.  When 802.3ae was starting, 802.3ad (Link Aggregation) had not yet completed, but there was a decision to support Link Agg in 802.3ae.  The 10GBASE-T Study Group will have to make decisions about what portions of 802.3, 802.3ae, 802.3af and 802.3ah that we feel we should support or at least consider supporting moving forward.  For example, do we use Clause 22 management or Clause 45 management?  If we use Clause 45 but wish to support auto-negotiation to lower speeds, then we may need to consider supporting Clause 22 access to Clause 45 registers.  802.3 is a living document, so we need to be careful about what parts we do and do not want to consider in our effort.
 
As the Chair, I want to make sure we consider all aspects of creating a standard, from the technical feasibility up to the management requirements.  All opinions are valid, and open discussion is a great way that we make sure we haven't left stones unturned.
 
Thanks,
Brad
-----Original Message-----
From: Ahmet Tuncay [mailto:atuncay@solarflare.com]
Sent: Monday, February 24, 2003 6:28 PM
To: stds-802-3-10gbt@ieee.org
Subject: RE: [10GBASE-T] EFM OAM...

Brad, if this isn't an invitation to get one into trouble, I don't know what is.  In any case, my input would be that we need OAM no more than 1000BASE-T does, so I'd favor leaving out of the scope of the 10GBASE-T PHY.  If someone wants to implement some level of OAM in a derivative PHY device or use MAC level OAM functions they're free to do so.
 
Also, from my limited understanding of 802.3ah, OAM for the PHY layer is TBD, so I don't think we can consider the work being done in EFM as useful precedence at this point.
 
-ahmet 
-----Original Message-----
From: Booth, Bradley [mailto:bradley.booth@intel.com]
Sent: Monday, February 24, 2003 3:00 PM
To: stds-802-3-10gbt@ieee.org
Subject: RE: [10GBASE-T] EFM OAM...

Geoff,
 
Would you like to make a presentation to that effect? :-)
 
I see the Study Group as having three options related to OAM in our objectives:
1) state compliance with EFM OAM (and therefore possibly use it in our effort)
2) state that EFM OAM is beyond the scope of 10GBASE-T, excluding it from use within our effort
3) say nothing, and leave the use of EFM OAM capabilities up to those implementing the systems
 
Which of the three options would you prefer?
 
Would anyone else like to state a preferred option?
 
Thanks,
Brad
-----Original Message-----
From: Geoff Thompson [mailto:gthompso@nortelnetworks.com]
Sent: Wednesday, February 19, 2003 8:23 PM
To: Booth, Bradley
Cc: stds-802-3-10gbt@ieee.org
Subject: Re: [10GBASE-T] EFM OAM...

Brad-

I would say that since...
        the same entity is likely to own both ends of the link
AND
        both ends of the link are expected to be in the same building.
AND
        both ends of the link are likely to be in the same room
that there is no need for management beyond that required for existing enterprise links.

Geoff


At 08:32 PM 2/18/2003 -0800, Booth, Bradley wrote:

Study group members,

As some of you may know, EFM (Ethernet in the First Mile or 802.3ah) has added Operation, Administration and Management (OAM) capabilities to their specification.  Like 802.3af DTE power, the study group needs to decide whether or not compliance with 802.3ah is within the scope of our effort, and most specifically the OAM capabilities.  This relates to compatability with our existing standards.  If there is anyone that would like to make presentations for or against compliance with 802.3ah or 802.3ah OAM, please let me know.

Thank you,
Brad

Chair, 10GBASE-T Study Group
bbooth@ieee.org