On Jun 24, 2015, at 3:52 PM, Brad Booth <bbooth@xxxxxxxx> wrote:
There will be 50 GbE on the server before there is 400G on the TOR and even before 400G task force gets to working group ballot. :-) It won't be 50G on a single lane though, but it will be 50G Ethernet.
Also, by the time 400G is on the TOR, there will be end users considering 100G (again, not on a single lane) to the server.
Cheers, Brad
On Wed, Jun 24, 2015 at 1:27 PM, Ali Ghiasi <aghiasi@xxxxxxxxx> wrote:
Paul
I said by "the time server and silicon technology catches where 400 GbE is integrated on the TOR”! In 1-2 silicon generation when 400 GbE is integrated on the TOR then you will also see 50 GbE on the server.
We are developing 25GbE because 10G is not sufficient for a segment of market and 25 GbE cost less than the alternative the 40 GbE. The same economic will apply to 50 GbE later on!
In order for 50G lanes to make sense for ToR switches, servers must be able to use that rate. I think the market will put 25G servers to several years of use before 50G servers overtake them. Witness the time lag for 10G servers to overtake sub-10G servers. 10G is now in its prime with 25G up and coming. If this is not true, why are we bothering to develop 25GE?
Paul
From:Ali Ghiasi [mailto:aghiasi@xxxxxxxxx] Sent:Wednesday, June 24, 2015 1:59 PM To:Kolesar, Paul Cc:STDS-802-3-400G@xxxxxxxxxxxxxxxxx Subject:Re: [STDS-802-3-400G] one comment about 4x100G breakout RE: IEEE P802.3bs 400 Gb/s Ethernet Task Force Logic Ad Hoc
Paul
Initial application of 400 GbE will follow 100 GbE early deployment SMF ports on Routers and Spin switches. Du Wenhua statement is correct to say 400 GbE will not be integrated initially on TOR. By the time server and silicon technology catches where 400 GbE will be integrated on TOR then we will have 50 GbE on single lane of SMF/MMF.
So 16x25G MMF has limited life/application and soon to be obsolete with emergence of 50G eco-system.
Du Wenhua, I thanks for your thoughts. This is a valuable discussion.
I do not disagree with your points on KP4 and KR4 FEC at 100G, but I have a different view on your conclusion point 3). I think 16x25G and 8x50G break-outs can play a role in ToR switch ports facing the servers. A port that delivers 16 lanes of 25G can provide transceiver cost advantages compared to discrete transceivers. It also provides electrical signal routing advantages because all electrical lanes can be of nearly the same minimal length rather than spread out to reach ports across the entire switch faceplate which alleviates the need for repeater chips saving cost and power.
Regards, Paul Kolesar
-----Original Message----- From: Duwenhua [mailto:duwenhua@xxxxxxxxxxxxx] Sent: Wednesday, June 24, 2015 3:36 AM To:STDS-802-3-400G@xxxxxxxxxxxxxxxxx Subject: [STDS-802-3-400G] one comment about 4x100G breakout RE: IEEE P802.3bs 400 Gb/s Ethernet Task Force Logic Ad Hoc
My comments: 1) What is the size of 1x400G KP4 & 4x100G KP4 FEC? 2) today 100GbE choose KR4,but I think that the breakout 100GbE will need KP4 FEC if the 100GbE SMF PMD choose 100G PAM4 in future. --In long term, serial is better than parallel. For 100GbE, 100G PAM4 SMF PMD is better than 4x25G SMF PMD. 3) same idea can be seen at page29 ofhttp://www.ieee802.org/3/bs/public/14_05/maki_3bs_01a_0514.pdf QSFP28 has a DSP&FEC which convert 4x25G to 1x100G.
My conclusions: 1) 4x100G breakout, the FEC should be able to dynamic changed: 4x100G KR4, or 4x100G KP4. 2) 4x100G breakout is very important in data center switch at the positions of Spine switch and Core switch, because face port density and flexibility. 3) 8x50G and 16x25G breakout is not important, because only TOR switch need 50G/25GE, but TOR switch do not have 400GE port.
-----Original Message----- From: Mark Gustlin Sent: Monday, June 15, 2015 10:59 AM To:STDS-802-3-400G@xxxxxxxxxxxxxxxxx Subject: RE: IEEE P802.3bs 400 Gb/s Ethernet Task Force Logic Ad Hoc
All,
Just a reminder of the upcoming logic ad hoc call. The current agenda is: 400GE FEC Implementation - Martin Langhammer Considerations for breakout - Martin Langhammer 1x400G vs 4x100G FEC Implications - Bill Wilkie
Requests are due by end of day Wednesday. There is room for only one more presentation for this call, so the next request will get the last slot. There is another opportunity on June 29th.