Re: Framing packets over the link
Hello Rich and Hon,
There is a Multilevel Signalling approach based on the 1000BASE-T
PCS and 4-WDM, using a baud rate of 1.25 Gbaud/sec in the optical
fiber (the "10G-BASE-T" proposal). This approach optimizes the
reuse of the installed, bandwidth limited, optical fiber used in 1 GbE.
The corresponding entries in the table would be:
1.1981 Gbaud/sec and 1.25 Gbaud/sec
for signalling rates of OC-192 and 10 Gb/s, respectively.
Jaime E. Kardontchik
Micro Linear
San Jose, CA 95131
email: kardontchik.jaime@xxxxxxxxxxx
Rich Taborek wrote:
> 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