Re: 9.584640
Hon Wah,
I has assumed that a 10 GbE MAC/PLS rate of 9.584640 was selected to EXACTLY
match the OC-192 payload rate independent of the coding on Ethernet or SONET
side of the line card. If this is NOT the case, then either or both of the
following are true:
1) Flow control is required REGARDLESS of the 10 GbE rate selected (i.e. #5a is
NOT TRUE). Therefore, 10.0 Gbps should be selected as the 10 GbE rate since it
will likely yield the lowest cost 10 GbE implementations.
2) Point #4 in my previous note is NOT TRUE. This means that more of SONET
signaling and framing would be imposed upon 10 GbE. This may include
requirements to operate at one or more of the EXACT line rates supported by
OC-192, SDL packet formatting, etc. This goes way beyond the simple HSSG speed
objective and only pushes the requirement to map Ethernet to SONET dowstream to
the slower speed Ethernet feeds. I view this as tantamount to declaring that 10
GbE "IS" SONET OC-192.
#4 There seems to be no intent by either side to consider any other changes but
speed as a HSSG objective. Therefore, Ethernet will remain a simple, general
purpose, packet-based transport, and SONET will remain a specific purpose
(MAN/WAN), synchronous transport no matter which way the decision goes.
Best Regards,
Rich
--
Hon Wah Chin wrote:
> With regard to your point 5a below, I was pointing out that to do framing,
> either flow control (because of coding overhead) OR new packet formating
> (SDL ?) would be required at that point, even at the slower OC-192 payload
> rate.
> I meant that this issue should be considered ALONG with the clocking issue.
>
> -hwc
>
> -----Original Message-----
> From: Rich Taborek [mailto:rtaborek@xxxxxxxxxxxxxxxx]
> Sent: Thursday, July 15, 1999 3:17 PM
> To: Hon Wah Chin; HSSG; Dan Dove
> Subject: Re: 9.584640
>
> Hon Wah,
>
> Thanks for kicking this issue off again!
>
> Hon Wah Chin wrote:
>
> > ---
> > :
> > :
> >
>
> In my conversations with several folks on both sides of the issue during the
>
> Montreal meetings, I've come to the conclusion that the root reasons to
> select
> either a 10 or 9.584640 Gbps are purely ease-of implementation based and
> have no
> :
> :
>
> 5) Consider a Ethernet to OC-192 line card (feeding a fiber or wavelength)
> in
> operation. Assume that receive and transmit paths are separate on the SONET
> side
> and related (i.e. full duplex) on the Ethernet side:
> a) Ethernet -> SONET @ 9.584640 Gbps: The Ethernet side can continuously
> feed
> the SONET link with no flow control required.
> b) Ethernet -> SONET @ 10 Gbps: The Ethernet side must be flow controlled
> to
> prevent over-feeding the SONET link
> c) SONET -> Ethernet @ 9.584640 or 10 Gbps: The Ethernet side can
> continuously
> source SONET data but will flow control or drop packets downstream whenever
> the
> network is congested.
>
> :
> :
>
> Best Regards,
> Rich
-------------------------------------------------------------
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
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