Re: Framing packets over the link
Hon Wah,
The purpose of this note is to complete the entries for multilevel and
multichannel signaling which don't appear to be complete in your note:
Fixing the Signalling Fixing the Throughput
rate at OC-192 Rate at 10Gb/s
Multilevel 4.79232 GBaud* 5.0 GBaud**
signalling
Multichannel 2.39616 GBaud/ 2.5 GBaud/
signalling 2.9952 GBaud*** 3.125 GBaud****
All entries assume an OC-192 PAYLOAD rate of 9.58464 Gbps and not any true
OC-192 line rate, since the current HSSG speed objective only considers a
MAC/PLS rate of ONLY 9.58464 Gbps OR 10 Gbps. There is no HSSG objective to
consider a line or signaling rate.
* Given an OC-192 MAC/PLS rate of 9.58464 Gbps, the fully encoded MAS line rate
proposed is half the MAC/PLS rate, or 4.79232 GBaud.
** Given a MAC/PLS rate of 10 Gbps, the fully encoded MAS line rate proposed is
half the MAC/PLS rate, or 5 GBaud.
*** Given an OC-192 MAC/PLS rate of 9.58464 Gbps, the unencoded multichannel (4
x WWDM or parallel optics) line rate proposed is one fourth the MAC/PLS rate, or
2.39616 GBaud per channel. The 8B/10B encoded multichannel (4 x WWDM or parallel
optics) line rate proposed is five fourths the unencoded rate, or 2.9952 GBaud
per channel.
**** Given a MAC/PLS rate of 10 Gbps, the unencoded multichannel (4 x WWDM or
parallel optics) line rate proposed is one fourth the MAC/PLS rate, or 2.5 GBaud
per channel. The 8B/10B encoded multichannel (4 x WWDM or parallel optics) line
rate proposed is five fourths the unencoded rate, or 3.125 GBaud per channel.
Best Regards,
Rich
--
Hon Wah Chin wrote:
> We still have to consider how to format and frame the packets
> once we get the speed of the MAC/PLS settled. Here is a start for a
> comparison
> table (read with a fixed width font) for some schemes.
>
> Fixing the Signalling Fixing the Throughput Rate
> rate at OC-192 at 10Gb/s
> (get to use regenerators) (Might have to do new PHY/PMD)
>
> FRAMING
>
> Manchester approx 5Gb/s throughput Must signal at 20Gb/s
> (sucks) (really hard)
>
> -- tradeoff about fast locking PLLs (hard)
> vs some scheme like running quarter speed transitions
> to indicate "no carrier"
> -- This would not be a serious contender
>
> 8B/10B approx 8 Gb/s throughput must signal at 12.5 Gb/s
>
> PPP/POS variable throughput variable througput
> 10Gb/s - some delta 10Gb/s +- some delta
> (depending on signalling rate)
>
> -- some kind of scrambling required to reduce chance
> of long runs
>
> Header/Length 10 Gb/s - epsilon throughput Can be 10 Gb/s throughput
> (SDL et al)
> -- would require changing MAC/PLS definition to provide
> packet length early
> -- framing acquisition logic required - parallel CRC
> checkers to search for byte/packet alignment
> -- some kind of scrambling required to reduce chance
> of long runs
>
> Multilevel NA ?
> signalling
>
> Multichannel NA ?
> signalling
-------------------------------------------------------------
Richard Taborek Sr. Tel: 650 210 8800 x101 or 408 370 9233
Principal Architect Fax: 650 940 1898 or 408 374 3645
Transcendata, Inc. Email: rtaborek@xxxxxxxxxxxxxxxx
1029 Corporation Way http://www.transcendata.com
Palo Alto, CA 94303-4305 Alt email: rtaborek@xxxxxxxxxxxxx