What is 802.3ae WAN-PHY?
Dear Gary,
Thank you for your intelligible feedback. Now I became convinced
that I speak English :-). I am happy to hear the Japanese style
here, Nicholl-san! But please feel free to say just Osamu, because
it helps me to trust (fake?) myself that I speak English.
http://grouper.ieee.org/groups/802/3/10G_study/email/msg01952.html
Also, thanks to you, I became convinced that we have some issues of
clock tolerance compensation in SONET-framing that Rich has pointed
out farsightedly.
http://grouper.ieee.org/groups/802/3/10G_study/email/msg01866.html
On the other hand, it seems to me that this community has consensus
that the ELTE, not the WAN-PHY with SONET framer, is the demarcation
point between SONET and Ethernet. In other words, WAN-PHY with SONET
framer or Uni-PHY with WIS (WAN interface sublayer) should not be
SONET. (All, please let me know if this is a wrong observation.)
http://grouper.ieee.org/groups/802/3/10G_study/email/msg01958.html
http://grouper.ieee.org/groups/802/3/ae/public/mar00/frazier_1_0300.pdf
Then why we need WAN-PHY or WIS other than ELTE?
The answer is in Mr. Paul Bottorff's slides in Albuquerque; the
router/SW requires minimal management capability of WAN.
http://grouper.ieee.org/groups/802/3/ae/public/mar00/bottorff_2_0300.pdf
Here I completely agree with Paul. This is indispensable to meet the
PAR scope "add parameters and mechanisms that enable deployment of
Ethernet over the Wide Area Network".
http://grouper.ieee.org/groups/802/3/ae/PAR-802-3ae.pdf
Then do we need SONET-frame between WAN-PHY and ELTE?
In my opinion, the answer is NO.
Once we have Mr. Shimon Muller's open-loop control to provide
OC-192c/VC-4-64c compatible MAC rate, my understanding of the need
for the SONET-framed PHY or WIS is limited to the OAM&P capability
supported by minimal overhead bytes in a SONET frame.
http://grouper.ieee.org/groups/802/3/ae/public/mar00/muller_1_0300.pdf
http://grouper.ieee.org/groups/802/3/ae/public/mar00/figueira_1_0300.pdf
Here you have another solution 10GENIE; Layer-1 signaling by using
interpacket gap.
http://grouper.ieee.org/groups/802/3/ae/public/mar00/ishida_1_0300.pdf
Assuming that 10GENIE can support the similar OAM&P to the ELTE, my
perspective says that 10GENIE would be cheaper than WAN-PHY and WIS;
no SONET framer (pointer manipulation), much less extra buffer for
OAM&P data insertion, no 9.95Gb/s CLK, no jitter-tolerance limitation.
I will shed light on this comparison in my up-dated 10GENIE proposal
in Ottawa.
Of course I have understood that 10GENIE has a tough problem indicated
by Mr. Steve Haddock; Who is going to define how to OAM&P?
http://grouper.ieee.org/groups/802/3/10G_study/email/msg01919.html
My perspective says that IEEE 802 is the only candidate to be able to
define it. I know that this don't suit the traditional 802.3's taste,
but still I hope to have your support to define it. Otherwise we
will see the law of the jungle until some de facto OAM&P has
established; we will see wasteful investment to every potential loser
and local dialect cutting the market into pieces. We will fail to
catch a golden opportunity to unify LAN/WAN hardware for datacom at
10 Gb/s; and may degrade huge unified market potential.
In Ottawa, I will show you how 10GENIE OAM&P is simple and easy-
interoperable. I will restrict it to non-negotiable functions.
I think this may be simpler than the auto-negotiation with config-
register defined in 802.3z Clause 37.
All, any feedback on this matter would be greatly appreciated.
Best Regards,
Osamu
At 4:08 PM -0400 00.4.3, Gary Nicholl wrote:
> I agree with Ishida-san.
>
> I think we need to understand that there are two separate issues here.
>
> (1) clock tolerance/accuracy specifications (i.e. +/-100ppm, +/-4.6 ppm, etc)
> (2) jitter budget specifications (jitter generation, transfer and tolerance)
>
> The first one determines the lock range of any oscillators and phase look loops in the network. In SONET the worst case clock accuracy/tolerance is specified as +/- 20ppm and therefore every oscillator and clock recovery circuit in a SONET network should be able to lock on and hold to a +/- 20ppm signal.
>
> The second one, as Ishida-san points out is, effectively determines the maximum number of through-timed regenerators that can be traversed on an end-end SONET link to maintain a specified link bit error rate.
>
> These two specifications (i.e. clock tolerance/accuracy and jitter) are completely intendant. However from my experience in dealing with POS (packet over SONET) there is a tendency among some people to assume that they are related, in that a more accurate clock (say 4.6ppm rather than 20ppm) necessarily has better jitter performance. This is not the case. In fact SONET has a single set of jitter specifications (generation, transfer and tolerance) that are the same irrespective of whether an interface is clocked from a stratum 1 clock, a stratum 3 clock (4.6ppm) or a 'SONET minimum' clock (20ppm).
>
> As a reference point POS interfaces use a 20ppm clock and are fully compliant with the SONET/SDH jitter specifications in Bellcore GR-253 and ITU G.958.
>
> Gary ........................
-----------------------------------------
Osamu ISHIDA
NTT Network Innovation Laboratories
TEL +81-468-59-3263 FAX +81-468-55-1282