Re: What is 802.3ae WAN-PHY?
Dear Dave, Dear Roy,
Thank you for your feedback and corrections. I would be pleased if
you could keep in mind that we had better use interoperable words
here in LAN community.
At 4:06 PM +0900 00.4.9, Osamu ISHIDA wrote:
http://grouper.ieee.org/groups/802/3/10G_study/email/msg02204.html
At 1:58 PM -0500 00.4.10, David Martin wrote:
http://grouper.ieee.org/groups/802/3/10G_study/email/msg02234.html
At 11:18 AM -0500 00.4.9, Roy Bynum wrote:
http://grouper.ieee.org/groups/802/3/10G_study/email/msg02211.html
I have changed 'SONET-lite' into the word 'SONET-framed', and removed
the word 'almost' from the overhead access of SONET. I hope in this
time this table suits your taste.
--------------- --------------- ------------ ----------- ------
expression Overhead access CLK Accuracy CLK Jitter Std.
--------------- --------------- ------------ ----------- ------
SONET full < +/-20ppm SONET spec. T1.105
SONET-compliant reduced < +/-20ppm SONET spec. T1.416
SONET-framed much reduced < +/-100ppm ?????????? ??????
--------------- --------------- ------------ ----------- ------
Here I assume that SONET-framed equals WAN-PHY with SONET framer
proposed in 802.3ae.
I have assumed that we agreed on the following two facts since I have
received no objections;
(1) There is no SONET-framed PHY standard at present. All SONET or
SONET-compliant equipment at present, including the emerging
non-muxing LTE, should meet +/-20ppm CLK accuracy and SONET
jitter spec.
(2) Pointer manipulation mechanism in SONET framer itself has
the potential to accommodate the CLK difference up to +/-320ppm.
Next what I would like to agree with you is the following;
---------------------- ------------------------- ------------ -----------
expression SONET function CLK Accuracy CLK Jitter
---------------------- ------------------------- ------------ -----------
old active transponder Section termination < +/-20ppm SONET spec.
new active transponder Section&Line termination < +/-20ppm SONET spec.
---------------------- ------------------------- ------------ -----------
Here I assume that new active transponder equals 'the emerging non-muxing
LTE' and hence equals Ethernet Line Terminating Equipment. According to
above (1), I have assumed that both transponders should be SONET or SONET-
compliant.
Why there are 'old' & 'new' active transponders? This is because I have
found that the definition of the active transponder seems to be waved;
old active transponder: see page 12 in
http://grouper.ieee.org/groups/802/3/10G_study/public/jan00/law_1_0100.pdf
new active transponder: see page 35 (last page) in
http://grouper.ieee.org/groups/802/3/ae/public/mar00/bottorff_2_0300.pdf
As far as I know, most of the install-base active transponders
are old type; only Section termination is performed. This implies that
the old active transponder equals SONET regenerator; no pointer
manipulation mechanisms, no clock domain exchange. This is a SNYCHRONUS
regenerator; it is designed to guarantee its performance under +/-20ppm
CLK accuracy specification.
Please let me know if this is a wrong observation.
What Mr. Gary Nicholl and I have asked repeatedly is that, since
SONET-framed PHY is not SONET-compliant, you have no guarantee for
the direct connection to these install-base old active transponder.
It may work, but it may not work. The old active transponder only
follows the SONET or SONET-compliant +/-20 ppm specifications.
Another unclear point is who will define the ELTE specification
at the Ethernet side (+/-100ppm). Roy said that it would be soon
defined by the other standard bodies, but Paul said ANSI would not.
At 11:18 AM -0500 00.4.9, Roy Bynum wrote:
http://grouper.ieee.org/groups/802/3/10G_study/email/msg02211.html
At 3:25 PM -0700 00.4.10, Paul Bottorff wrote:
http://grouper.ieee.org/groups/802/3/10G_study/email/msg02239.html
In this situation, I could not believe that ELTE would be defined
outside IEEE802.3ae unless SONET-framed PHY keeps +/-20ppm spec.
Have I mis-understood you? Can you please shed more light on
something I'm missing?
Best Regards,
Osamu Ishida