Re: [802.3_NGEPON] Upstream Wavelength Plan

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Dear 802.3ca colleagues:

There are some interesting discussions on wavelength plan, coexistence etc. recently. Here are my two cents on the direction the discussions may lead to and the impact on long term PON evolutions.

The asymmetric 10G/25G. There are renewed discussions on asymmetric 10G/25G this week. A new 10G wavelength was discussed. The 10G/25G topic has been discussed for some time-- in the July 2017 contribution dai_3ca_1a_0717.pdf , I discussed the needs for 10G/25G as a low cost 25G solution. Therefore, I fully support the asymmetric 10G/25G as an important bridge to 25G/25G. However, creating a NEW wavelength for 10G defeats the purpose of having asymmetric 10G/25G standard and the details are already outlined in the above-mentioned reference. What I want to emphasize here are few drawbacks of this approach. Firstly, it will create a new legacy 10G upstream standard. Secondly, it will not benefit from the existing 10G PON (10G EPON and/or XGS-PON) optical components markets. Thirdly, it will unnecessarily erode the highly demanded O band resource for the future high-speed PON.

WDM and TDM coexistence. We must keep in mind that coexistence is transitional, it is for the past; the new wavelengths allocated for coexistence are permanent and will impact the future. If possible, we all prefer WDM coexistence. But creating a new 10G wavelength and a new 25G wavelength solely for the purpose of WDM coexistence is not worth it. TDM coexistence simply provides another degree of freedom in the complicated scenario we are facing.

Chromatic dispersion penalty. If we have two 20nm channels in any band, there will be dispersion penalty variations. This is no difference from full C band DWDM. We need to run some simulations to study it impacts and evaluate other solutions before start to move wavelengths around.

Regards,

Eugene

From: Marek Hajduczenia [mailto:mxhajduczenia@xxxxxxxxx]
Sent: Friday, January 05, 2018 8:37 AM
To: STDS-802-3-NGEPON@xxxxxxxxxxxxxxxxx
Subject: Re: [802.3_NGEPON] Upstream Wavelength Plan

Would this arrangement then be more acceptable? While I do understand that some operators might be more interested in asymmetric systems, at the same time, 10G system side is more forgiving in terms of transmission penalties, so both 25G channels should be as close to each other as possible to make them present as similar penalties as possible to simplify the design of 2x25G optics.

From: Liudekun [mailto:liudekun@xxxxxxxxxx]
Sent: Friday, January 5, 2018 3:16 AM
To: Marek Hajduczenia <mxhajduczenia@xxxxxxxxx>; STDS-802-3-NGEPON@xxxxxxxxxxxxxxxxx; Harstead, Ed (Nokia - US) <ed.harstead@xxxxxxxxx>
Subject: RE: [802.3_NGEPON] Upstream Wavelength Plan

All：

Just a comment on “We have enough spectrum to optionally allow WDM coexistence between 25G and 10G systems”

I don’t think we have ample spectrum which we allow we allocate the wavelength plan casually.

All the wavelength we discussed here are low dispersion O-band, they are very precious spectrum for high speed PONs, including the even higher speed PON systems.

The low dispersion band is very limited, we should use them in an efficient way.

The asymmetric ONUs are always the major volume, so a symmetric OLT are often required to support the asymmetric ONUs ( maybe some operators don’t care 25/10, but there are definitely some other operators quite interesting on 25/10), it will be a big waste to allocate a different wavelength band for asymmetric systems.

To Ed:

I am interesting on the upstream wavelength plan, so please add me in to the discussion email list. Thanks.

Best regards

Dekun Liu

____________________________________________________

Advanced Access Technologies Dept. 网络研究接入技术部

Huawei Technologies Co., Ltd. 华为技术有限公司
Phone: +86 027-59267217 Email: liudekun@xxxxxxxxxx

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From: Marek Hajduczenia [mailto:mxhajduczenia@xxxxxxxxx]
Sent: Friday, January 05, 2018 5:13 AM
To: STDS-802-3-NGEPON@xxxxxxxxxxxxxxxxx
Subject: Re: [802.3_NGEPON] Upstream Wavelength Plan

That might James' opinion. I do not share it. We have enough spectrum to optionally allow WDM coexistence between 25G and 10G systems.

At the end of the day, I personally do not care about new 10G upstream, but only about making both 25G channels equally challenging and limit their dispersion penalty. I do know though that the optional ability to do 10G and 1G upstream separation in today's system is a saving grace in many deployments where these systems are overlapped on the same fiber strand. I do not see any advance of doing the overlap if we can have some separation between these systems

On Thu, Jan 4, 2018 at 2:08 PM, John Johnson <john.johnson@xxxxxxxxxxxx> wrote:

Marek,

zhang_dezhi_3ca_2a_1117 proposed the principal that different rates in the same PON generation should share spectrum by TDM. I think that this principal should apply to 25G and 10G (using 25G protocol) upstream.

Ed, please add me to your list.

Inline image 1

Regards,

John

On Thu, Jan 4, 2018 at 3:08 PM, Marek Hajduczenia <mxhajduczenia@xxxxxxxxx> wrote:

Ed et al.,

Here are two versions of what I was suggesting, depending on how we want to stack red 25/10G options

Please include me in the discussion chain.

Thanks

From: Harstead, Ed (Nokia - US) [mailto:ed.harstead@xxxxxxxxx]
Sent: Thursday, January 4, 2018 12:48 PM
To: STDS-802-3-NGEPON@xxxxxxxxxxxxxxxxx
Subject: [802.3_NGEPON] Upstream Wavelength Plan

All,

Per the discussion on today’s call: For anyone interested in joining the small group working to achieve consensus on the upstream wavelength plan, please send me an email.

From: Curtis Knittle [mailto:C.Knittle@xxxxxxxxxxxxx]
Sent: Wednesday, January 03, 2018 4:09 PM
To: STDS-802-3-NGEPON@xxxxxxxxxxxxxxxxx
Subject: [802.3_NGEPON] 1/4/18 IEEE 802.3ca (100G-EPON) consensus building meeting agenda