Re: What is 802.3ae WAN-PHY?
Dear Praveen,
Your illumination on "preserving the notion of section, line & path"
guided me to re-consider "How far 10GENIE can support SONET
functionality and its overhead bytes?"
The answer in my heart at present is "Everything, if you want".
My careful consultation with ITU-T G.707(03/96) where SDH overhead
bytes are defined, this was like a whole day reading of a myth
written by Latin even to me, has now convinced me that 10GENIE can
support almost all the OAM&P in the existing SONET/SDH infrastructure.
In other words, if you want, the Ethernet LAN-PHY with 10GENIE can
send/receive all the SONET/SDH OAM&P information or its equivalence
without using SONET frame.
Only exception is the B2 bytes in line overhead; bit interleaved
parity (BIP) 1536 (= 8*192 bits). The B2 bytes enable us to monitor
the Line bit-error-rate (BER) of 10^-3 or lower, whereas the B1 byte
(Section BIP8) or B3 byte (Path BIP8) supports BER of 6*10^-6 or
lower. I do not believe this sensitivity up-grade is worth consuming
192 bytes per 100 Ethernet Packets.
Of course I know we need some mapping or conversion in ELTE; one
example is the bit-error-rate monitor that will be equivalently
supported by the 8B/10B code violation or the 64/66 two-bit-header
violation monitor. However, at present, I see no significance in
these mapping/conversion issues if we remind the fact that LAN-PHY
with 10GENIE is a real Uni-PHY; no physical WIS (SONET framer).....
No, this is not true, we still need WIS for 10GENIE ordered-set
insertion/removal, but I think this is much simpler than the SONET
framer.
As for the ratio of overhead to payload, I do not think it
unpredictable. What Mr. Shimon Muller proposed in Albuquerque is
that we have minimum guaranteed IPG bandwidth in the average, isn't
it? Furthermore, if we carriers want, we can choke the MAC rate to
steal the customer's bandwidth :-). What a nice system Shimon has
invented!
http://grouper.ieee.org/groups/802/3/ae/public/mar00/muller_1_0300.pdf
Anyway, I greatly appreciate your interest on the 10GENIE approach.
Best Regards,
Osamu
http://grouper.ieee.org/groups/802/3/10G_study/email/msg01965.html
http://grouper.ieee.org/groups/802/3/10G_study/email/msg01968.html
http://grouper.ieee.org/groups/802/3/10G_study/email/msg01971.html
At 7:59 PM +0900 00.4.5, Osamu ISHIDA wrote:
> Jonathan, Praveen,
>
> Thank you for your feedback.
>
> (1) I want to know "Why SONET framing" just for the short jumper to ELTE.
> How it acieves "low cost" WAN access? What is its basis?
> Any perspective on the SONET framer side would be greatly appreciated.
>
> (2) I do not see any critical issues regarding the amount of OAM&P data.
> I do not expect full-SONET compatibility in 10GENIE, especially here
> in 802.3ae. But even in full compatibility, SONET overhead bytes
> defined for OAM&P are less than 30 bytes/125us(=155,520 bytes) if we
> exclude the 192 bytes for B2 (Strong bit-interleaved parity for Line).
> This includes all section/line/path overhead bytes except the B2.
> 30 bytes for every 100 Ethernet Packets (=100 IPG) sounds easy to me.
>
> Best Regards,
> Osamu
>
> At 11:21 AM -0700 00.4.4, Praveen Kumar wrote:
>>>Question: while the 1:1 logical connection is easy for me to make, would
>>>there be any issue regarding the amount of data that could be carried in the
>>>SONET overhead compared to the amount of data that could be carried in the
>>>IPG?
>>
>> I think there is still quite some work to be done with respect to mapping
>> the SONET (or OAM&P) overhead onto the IPG. For example, even if we decide
>> to use the IPG to carry the overhead, it would still be useful to preserve
>> the notions of section,line & path. How is this layered overhead going to be
>> distributed. Also, it would still be useful to allow multiple 10G signals to
>> be multiplexed to a higher rate signal downstream. SONET framing does all of
>> this for us TODAY.
>> Another issue associated with using IPG to carry overhead is that, the ratio
>> of overhead to payload is now a function of payload (packet) size. This
>> means that the bandwidth consumed by the overhead channel (IPG) is now
>> unpredictable and Iam not sure if carriers are going to like this.
>>
>> Nevertheless, I see some benefits associated with the 10GENIE approach. I
>> think the question of "Why SONET framing" has not been convincingly answered
>> by the "WAN PHY" proposal. For example, SONET is not the only transport
>> network. What if one needs to connect the 10G WAN link to an all-optical
>> (non-SONET) wavelength switched transport network. Is the STS signal the
>> most optimal in this scenario?
>>
>> -Praveen