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Re: [802.3BA] 40G/100G SMF distinct identity [WAS: RE: [802.3BA] 5 Criteria mod to support 40 G on SMF]

On Sat, 16 Feb 2008, Alessandro Barbieri (abarbier) wrote:

> This group has identified a minimum set of applications that is 
> sufficient to justify the DI of 40G and 100G, that should be enough. We 
> can't pretend 40G will not find its way into the aggregation. Much like 
> in 10-12 years 100G will find its way into the server market.

Sorry for my previous email where I used "price" instead of "cost". I'll 
try to improve.

So, backing up a bit, I'm trying to see this from a system perspective, ie 
in the equipment where these technologies are going to be used.

I have some thinking I would like some vendors to give feedback on, which 
I think is important in this decision as well.

Currently, a lot of the current highend platforms use 40 gigabit/s 
backplane connectivity. Would they get 40GE support on the current 
chassis/fabric generation in 2010?

By 2010, my guess is that highend platforms will have backplane 
connectivity somewhere in the 100, 120, 160 or 200 gigabit/s speeds.

If 100, this would enable single port 100GE or two port 40GE blades.
If 120, this would enable single port 100GE or three port 40GE blades.
If 160, this would enable single port 100GE or four port 40GE blades.
If 200, this would enable dual port 100GE or five port 40GE blades.

Would the 40GE blades have pluggable optics that would support all 
proposed reaches? If there is a push for 10km SMF reach for 40GE, why not 
40 or 80km reach there as well? With 3 or 4 port 40GE blades one would 
have capacity to on a single blade create rings and then use 40GE as 
aggregation technology immediately. Then it makes sense to have 10 and 
40km SMF reaches (and seeing that 10GBASE-ZR is actually used quite a bit, 
wouldn't 80km as well be of interest to standardize by the same logic that 
vendors will standardize 40GE-10km SMF if IEEE doesn't)?

I also think that any proponent for 40GE needs to explain what the next 
step after 100GE should be, as 40GE creates a precedent for 250GE or 400GE 
as next step if the logic is to be intact.

Being a data communications guy, I don't understand why FC seems to be 
increasing by factor 2 each generation, instead of factor 4 or 10. 
Representatives for Brocade (in my mind primarily FC vendor) says 
customers want small increases in link speed, which is not my experience. 
In the ISP world people often want to use their equipment for a long time 
and write them off in 3-6 years, as they are usually quite big and big in 
capital spending, thus the need for factor 4 or 10 in speed increase 
over the previous generation.

I also feel that 40GE was pushed as server technology needed in 2012, in 
order to make 40GE worthwile it needs to be here before 100GE, not after, 
or show big cost savings so as to be more economical per bit compared to 
100GE. Being compatible with existing equipment (new linecard for existing 
platforms) might cause it to be more economical for end users from a total 
expenditure perspective.

Being an ISP guy, I also feel that any push for 40GE needs to have broad 
switch/router vendor support, because if the core routing platforms 
doesn't support 40GE then there is a big hurdle in how to connect the 
aggregation to the core for any larger sized ISP who has a WAN.

But then again, if 40GE 10km SMF uses a lot of 10GE technology and has a 
2.5x cost increase over 10GE, and 100GE has 10x cost increase, and 40GE 
can be brought quickly to market and 100GE will take more r&d and is 
harder to realise, then 40GE SMF might still have a place.

But I do have to say again: 40GE cannot delay 100GE effort, it's needed 
soon of not NOW. 40GE is bandaid for ISPs, the solution is 100GE if not 
higher speeds, or we risk stalling the growth of the Internet.

Mikael Abrahamsson    email: