RE: Clock Tolerance and WAN PHY
Correction to my previous reflector note.
At 23:55 01/01/27 +0900, Osamu ISHIDA wrote:
> Instead, I recommend vendors to support one more MAC rate of
> 9.61 Gb/s. This will allow us to map 64/66-encoded LAN-PHY signals
> into OPU2 by simply deleting the inter-frame Idles.
>
> (9.61 Gb/s = 9 953 280 kbit/s * 64/66 * 237/238)
The recommended MAC rate for the OTN should be 9.69 Gb/s.
(9.69 Gb/s = 9 953 280 kbit/s * 64/66 * 238/237)
Best Regards,
Osamu
At 23:55 01/01/27 +0900, Osamu ISHIDA wrote:
> Hi Gary, and All,
>
> Here is the clock and its tolerance of the client signal for G.709 OTN
> (Optical Transport Network) that will be approved by ITU-T (Feb 2001).
> It does not support the direct mapping of 10.3 Gb/s LAN-PHY signal.
>
> a) it accepts OC-192c (9 953 280 kbit/s) format with approximately
> +/- 45 ppm clock tolerance (CBR10G asynchronous mapping into OPU2)
> OPU2: Optical Channel Payload Unit 2 (OPU1 is for 2.5G, OPU3 is for 40G)
>
> b) it accepts OC-192c (9 953 280 kbit/s) with +/- 20 ppm tolerance
> (CBR10G bit-synchronous mapping into OPU2)
>
> c) it accepts bit stream (approximately 9 995 276.962 kbit/s) with
> +/- 20 ppm tolerance
> (Mapping of non-specific client bit stream into OPU2)
>
> The possible directions I see in the 802.3ae WAN-PHY are;
>
> 1) no change.
> WAN-PHY signal with +/- 100 ppm tolerance will be accommodated into
> OTN by ELTE (i.e. by using SONET pointer manipulation mechanism).
>
> 2) reduce the WAN-PHY clock tolerance to +/- 45ppm.
> This will allow us to map the WAN-PHY signal into OPU2 directly if
> the OTN edge equipment supports asynchronous mapping (i.e. byte
> stuffing mechanism similar to that using the SONET H3 byte).
>
> 3) reduce the WAN-PHY clock tolerance to +/- 20ppm.
> This will allow us to map the WAN-PHY signal into OPU2 directly
> even if the OTN edge equipment only supports bit-synchronous mapping
> (i.e. WAN-PHY clock is used in the OTN signal as well).
>
> I have no preference in the above three directions since my own
> interest is to have 9.29 Gb/s MAC rate from the LAN Equipment.
> Instead, I recommend vendors to support one more MAC rate of
> 9.61 Gb/s. This will allow us to map 64/66-encoded LAN-PHY signals
> into OPU2 by simply deleting the inter-frame Idles.
>
> (9.61 Gb/s = 9 953 280 kbit/s * 64/66 * 237/238)
>
> Best Regards,
> Osamu
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Osamu Ishida,ishida@xxxxxxxxxxxxxxxxxxx
NTT Network Innovation Laboratories
TEL:+81-468-59-3263 FAX:+81-468-55-1282
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