Re: [802.3BA] Why 40GE and not 50GE?
Title: Why 40GE and not 50GE?
believe the original 40 Gb/s rate was primarily based on the anticipated
lower cost of using 4 X existing 10 GbE PHY technology. Four lanes has
significant history in our data paths (e.g., 1000BASE-T, 10GBASE-X4 PMDs, XAUI,
etc.) When P802.3ap was in development, it was generally expected that
backplanes could and would be built with 4 10GBASE-KR channels going to a
slot, allowing a future upgrade to 40 Gb/s through a single MAC.
Similarly, in the HSSG many advocates used assumed that other 10GBASE-R
technologies could be used in a four lane configuration to provide a higher
speed connection for servers at lower cost than 100 Gb/s. OTN
compatibility at 40 Gb/s was not an original driving force in the choice of
speeds for most advocates. Just as 10 GbE is 10.0000 Gb/s, so also did the
original advocates for 40 Gb/s mean 40.0000 Gb/s.
From: Frankel, Michael
Sent: Monday, February 18, 2008 7:11
Why 40GE and not 50GE?
I appologize ahead of time if this question has been
addressed. I looked over past HSSG material, and cannot find any info on
how specific 40GE rate came about (as opposed to 50 GE). 40G simply
appears as a "fact" in all the presentations.
Is 40G a default selection because of its ties to
OC768 and OTU3?
The only item I found is Slide 5 of following
presentation mentions PCIe x16 Gen2 as 50 Gbps of bandwidth.