Re: [STDS-802-3-EPOC] Minutes
Hi Ed,
Just a quick thought from my side: do we really need to store detailed statistics for all CNUs in the CLT PHY ?
As far as link quality per-subcarrier(-group) is concerned, it seems to me that the CLT PHY may need to be aware of that only for the CNU that is trying to accomplish PHY acquisition/auto-negotiation. That information is needed for PHY layer procedures, e.g., determining supported MCS (per-plant or for this specific CNU, it does not matter). The US PHY Link could potentially be used also for periodic updates of this kind of information. I believe this could be a topic for the PHY Link ad-hoc.
Of note, when using MMP, the CLT PHY may store the MCS associated with each CNU. But that would require much less memory space (single value for each CNU).
On the other hand, as you say we do need statistics on the PHY link quality for debugging and management purposes. My thought was that this kind of information could be conveyed from the CNU to the CLT via upper layer procedures (e.g., OAM). In this way, storage capabilities of the PHY layer should not be a concern.
Hope this makes sense.
Thanks,
Nicola
From: Ed (Edward) Boyd [mailto:ed.boyd@xxxxxxxxxxxx]
Sent: 13 February 2013 00:52
To: STDS-802-3-EPOC@xxxxxxxxxxxxxxxxx
Subject: Re: [STDS-802-3-EPOC] Minutes
Hi Marek,
I found the same results as Duane in the specification. The MDIO is a 16 bit address with half for vendor specific but 30K+ register addresses still available. It seems that we have lots of address space if we need it. We could easily add a layer of indirection to mux selected banks of statistics. For example, on the CLT PHY, we could have a register to choose which CNU to monitor. As I mentioned on the call, I don't think that the address space should be a reason for including or not including a statistic or monitoring function. The question is whether the statistics are needed to properly monitor the link and enable algorithms to handle channel conditions.
As someone who spends a lot of time debugging systems, I'm a huge fan of monitoring statistics. Large blocks of statistics are often implemented in RAM so the cost can be reasonable. Based on the testing that we have done so far on EPoC, I would like to see many statistics included in the standard. This system is much more complicated to debug than EPON and the statistic have been the only way to resolve issues and tune the system for higher performance. We could decide to split the statistics into a basic (required) set and an extended (optional) set. Operators could specify a particular supported level of statistics in the PHY. I think that we have done this in the past on other managed devices. Obviously, Broadcom, SIEPON, or CableLabs could use the vendor specific address area to specify the extended statistics but I'm not sure if that is the best solution. Just a thought.
Thanks,
Ed....
From: Marek Hajduczenia [mailto:marek.hajduczenia@xxxxxxxxx]
Sent: Tuesday, February 12, 2013 2:14 PM
To: STDS-802-3-EPOC@xxxxxxxxxxxxxxxxx<mailto:STDS-802-3-EPOC@xxxxxxxxxxxxxxxxx>
Subject: Re: [STDS-802-3-EPOC] Minutes
Duane,
I believe you'd agree that creating a set of a few thousand registers for each CNU on the CLT would be at least "frivolous". The reason why I brought it up during the call today was that I did not really know what to expect and contrary to some opinions voiced on the call, register space is limited and does have associated cost, so the fewer registers we actually need, the better for us. We do have some register space left, but again, going and consuming a large share of that for just one project would not be a good way forward IMO.
Regards
Marek
From: Duane Remein [mailto:Duane.Remein@xxxxxxxxxx]<mailto:[mailto:Duane.Remein@xxxxxxxxxx]>
Sent: Tuesday, 12 February, 2013 9:53 PM
To: STDS-802-3-EPOC@xxxxxxxxxxxxxxxxx<mailto:STDS-802-3-EPOC@xxxxxxxxxxxxxxxxx>
Subject: Re: [STDS-802-3-EPOC] Minutes
Steve,
Sorry to have missed this call.
FYI I would have vote "Yes" on each of the straw polls.
I note from Table 45-3 that there are close to 31,000 registers still available and that some past projects have reserved large blocks of registers (see 1.340 through 1.699 & 1.740 through 1.1099 for example), apparently for some future function so it doesn't appear we are in jeopardy of breaking the bank on MDIO registers. That said I don't disagree that we should not be frivolous; defining sub-carrier groups could go a long way to conserving this limited resource.
Best Regards,
Duane
FutureWei Technologies Inc.
duane.remein@xxxxxxxxxx<mailto:duane.remein@xxxxxxxxxx>
Director, Access R&D
919 418 4741
Raleigh, NC
From: Shellhammer, Steve [mailto:sshellha@xxxxxxxxxxxxxxxx]
Sent: Tuesday, February 12, 2013 3:09 PM
To: STDS-802-3-EPOC@xxxxxxxxxxxxxxxxx<mailto:STDS-802-3-EPOC@xxxxxxxxxxxxxxxxx>
Subject: [STDS-802-3-EPOC] Minutes
All,
Attached are the minutes of the RF Spectrum Ad Hoc call. For those who were not on the call we held several straw polls which you can review.
Steve
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