[802.3_100GCU] ad-hoc meeting 10/11/2012 meeting notes
802.3bj PAM4 Interference Tolerance PAM4
2012 October 11: 1200 MDT
Attendees:
Adam Healey LSI
Adee Ran Intel
Ali Ghiasi Broadcom
Alexander Umnov Huawei
Charles Moore Avago
Chung-jue Chen Broadcom
Elizabeth Kochuparambil Cisco
Galen Fromm Cray
Jeff Slavick Avago
Matthew Brown APM
Megha Shanbhag TE
Mike Dudek QLogic
Mike Li Altera
Pavel Zivny Tektronix
Rich Mellitz Intel
Vasudevan Parthasarathy Broadcom
Vittal Balasubramanian Brocade
Wheling Cheng Juniper
Will Bliss Broadcom
Zhongfeng Wang Broadcom
Notes thanks to Jeff Slavic.
Duration ~90min
Asked if anyone is not familiar with the patent policy of IEEE?
No responses
Reviewed the 100G Basekp4 Interference tolerance ad hoc slides
Slide 3
Option 1 not viable, since it was turned down in Sept
Interim
Option 2 not viable, since it relies on qikSN which is
not being used
Option 3 look into
Option 4 do we need to change what we specify?
Should the PMD testing be done w/o the presence of FEC?
No consensus
Slide 4 - Option 3
Do we need to stress the voltage and timing in two
separate tests?
Option 4
Do you need to test the system as a whole? Since that
is the environment that you’re running in, otherwise you have to add
more testing to validate with FEC enabled. Should we validate with FEC?
Do we want to remove the Max BER w/o FEC from Table 94-7 since it’s
always present? Depends on if we can test with FEC data streams or not.
Need to define tests for:
Ability to receive data assuming proper timing, vertical
stress.
Check the CDR operation, horizontal stress.
Suggestion create 2 tests:
1) Jitter tolerance test – no voltage stressing, validate SJ
tolerance, high amplitude, low frequency
2) Interference test - includes some SJ @ high freuqency
Back in ap days we had long discussions and the result was that we should:
Assume WC transmitter and WC channel. Which includes low & high
frequency jitter and WC channels includes high interference.
Can the view of the Rx tesing be done with:
2 COM values
1) Interconnect
2) Rx tolerance value
How do you define the WC Tx and WC channel? COM is comprised of
multiple inputs, so you have to bound both COM and values.
How do you cover this with minimal tests? What is independent and
correlated or orthogonal?
Do we assume that Tx COM is WC always?
Suggestion
Should we specify it as target COM at Rx input. The delta between test
COM and WC channel is the Tx COM + noise + test setup + jitter + etc.
Ceate N tests that all have the same COM at the Rx input. Build up the
tests to reach that COM level using each of the WC values. Need to
make sure it’s feasible to build it.
High Atten channel
High RJ
Short channel + DJ
Channel + Vert noise
Adi ‘s thoughts emailed to group of attendees in this file: *RX
tolerance ad-hoc initial ideas.pptx *
Integrate channel spec (COM) into Rx tolerance tests
Propose that the JTOL is handled separately
Loss: 2 cases one low, one high
COM: Up the COM to meet the target by adding in other
sources of interference
Jitter: low and high frequency, 2 tests
SNDR: of the transmitter can be calculated, compensated
with noise if not WC
Pattgen w/ FEC??? How do we get this?
Since we’re not a perfect world, how do you create the perfect with
imperfection until perfection is available?
Instruments would be required to supply FEC data + 90/92 frame markers.
To do a post FEC testing, need to have instrument that transmit data out
4 lane. Pattern would need to be 5440 / 2 long if that repeats
uniformly over 4 lanes and we can send RAMs, otherwise it’s way too
between AMs.
Can we use Annex 69A? Matt thinks that we’ll have to rewrite Annex 69A
and create an Annex 94.X. May have to overhaul Annex 69A for 93A.
Action items:
1. Define a pattern used for PAM4 to be used for testing of the Rx, and
determine if it’s feasible for current equipment to supply the
pattern. Will Bliss will take this on. Pavel will help Will
understand the capabilities of the equipment. Due date of 10/25/2012
ad-hoc meeting.
2. Group will try to get email dialog going for driving some of the
solutions.
3. Charles supply minutes and list of attendees
4. Adi to expand on his presentation, look at adding a version of Table
94-7.
Next meeting: 10/25/2012 for 90min @noon Mountain Time.