Hal,
I believe there will be contributions catering to your request – I am aware of at least two which will bring in discussion on the functional requirements for such devices. Note that given we are still at SG phase, the technical discussion is by necessity kept at the high level. We will have time at TF stage to discuss these in greater detail
Mare006B
From: Hal Roberts [mailto:Hal.Roberts@xxxxxxxxx]
Sent: 05 March 2012 14:32
To: Marek Hajduczenia; STDS-802-3-EPOC@xxxxxxxxxxxxxxxxx
Subject: RE: [802.3_EPOC] 回复: Re: [802.3_EPOC] What is the problem with the EPoC converter, and what is the CLT?
Marek,
Yes, I do mean 1G-PON. You are correct that 10G-EPON would practically preclude a simple PHY-PHY converter.
I did read the parallel threads, which is why I said ‘or something that has properties of a bridge’.
It would be interesting to have a list of the functions that the OCU or CLT (which is it?) must have, such as rate adaptation. That might reduce the ‘bridge’, ‘converter’, ‘repeater confusion.
Another topic best discussed in Hawaii.
Regards,
Hal
Hal,
We have been already a few times through what bridge is and why it is not a good idea to use it in the context of EPoC. Please review parallel email threads on this reflector.
As for the spectrum width you mention – given the spectrum block you mention, you do mean 1G-EPON, right? That would have to grow 10-fold to accommodate full 10G-EPON data rate if I am not mistaken/
Regards
Marek
Jorge,
“Instead, the CNU should provide a PHY-layer translation”.
If a minimum EPoC channel size that would be capable of carrying the entire EPON traffic was acceptable to MSOs, then a PHY-layer translation would be all that is necessary. This channel must be 125MHz to 150MHz depending on spectral efficiency on both the upstream and downstream.
What I heard in Newport Beach was this minimum channel size would be absolutely unacceptable. If so, the OCU or CLT capacity will be less than the EPON capacity, thereby requiring rate adaptation.
It is the rate adaptation and desire for flexible assigned spectrum that makes this more complicated and dictates the need for a bridge (or something that has properties of a bridge).
Best regards,
Hal
Here is the translation of Yao Yang's Email…
Sorry, I did not learn English, had to use the Chinese reply.
"The Bridge" is the second floor, which is the data link layer (MAC) device,Broadcom patent in the name of the CMC, meaning "Coaxial Media Converter -the conversion of the physical layer. My mail is actually raised questions about the purely physical layer conversion. But we hope that the MAC layer is notdivided into two sections - light and power for some, that is, do not want them abridge device. In China, EoC was originally named "Cable Bridge", the short board is not end to end. We believe that the solution to the problem is one of theexpansion of EPON the MPCP protocol, called does not matter what the CMC(or the OCU, or the ECB) to change the frame format, and perhaps increase the number of predicted frames, while forwarding data storage, but keep the OLTcontrol of the CNU, management, scheduling.
I think we are in agreement. He OLT should control both the ONU and the CNU. And, the converter, or OCU, should not bridge two different MACs. Instead, the CNU should provide a PHY-layer translation. Please let me know if this is what you are in favor of.
姚洋，
我覺得我們是一致的。他OLT的控制ONU和本校。和轉換器，或OCU的，不應該縮小兩個不同的MAC。相反，本校應提供PHY層的翻譯。請讓我知道如果這是你贊成。
謝謝！
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“桥”应该是二层、也就是数据链路层（包括MAC）的设备，博通专利中的名称是CMC，意思是“Coaxial Media Converter”——物理层的转换。我的上一个邮件实际是对单纯物理层转换提出了疑问。但是我们希望MAC层不要分成两段——光和电各一段，也就是不希望当中有个桥接设备。在中国，EoC最初就是以“缆桥”命名的，其短板就是不能端到端。我们认为，解决的方案之一就是扩展EPON MPCP协议，在CMC（或者OCU、或者ECB，叫什么不重要）变换一下帧格式，也许还要增加一些预测帧，同时对数据存储转发，但是保持OLT对CNU的控制、管理、调度。
2012-03-04
姚永
主题：Re: [802.3_EPOC] What is the problem with the EPoC converter, and what is the CLT?
David-
As I discussed in my earlier message,
your statement below:
‘Bridge’ is actually the more generic term.
is not correct.
In IEEE 802, a "bridge" is not a generic term.
Rather, it is a specific type of device whose configuration in standardized in 802.1
Best regards,
Geoff Thompson
On 23//12 11:42 PM, Barr, David wrote:
Yes, I agree with Jorge, Valy, Satish & Mr. Yao (SARFT), that a Bridge makes more sense.
‘Media Converter’ implies a PHY-layer hub, which will not be optimum for coax.
MACs are just digital logic, which are fully exposed to Moore’s Law.
Why preserve the MAC, if it becomes a vanishingly small part of the solution?
Particularly when preserving the sub-optimum MAC ruins the economics on coax.
‘Bridge’ is actually the more generic term.
The advisable approach is to bridge to coax-optimized technology,
with IEEE focusing on specifying the manageability & provisioning across that bridge.
-Dave
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