RE: [802.3ae] Clause 49 - 64b/66b Control Codes Mapping and Bit O rder
It looks fone to us.
Thanks,
-Jeff
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> From: "THALER,PAT (A-Roseville,ex1)" <pat_thaler@xxxxxxxxxxx>
> To: Tuan Hoang <tuanh@xxxxxxxxxxxx>, stds-802-3-hssg@xxxxxxxx
> Subject: RE: [802.3ae] Clause 49 - 64b/66b Control Codes Mapping and Bit O
rder
> Date: Tue, 22 Jan 2002 12:12:51 -0700
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>
> Tuan,
>
> First I would like to clarify something. 10GBASE-R O codes are not a recent
> addition - only the name is new. If you look at walker_1_700.pdf page 19,
> you will see the fields marked x and y. These contain the O codes though he
> didn't call them that.
>
> Note that the bits aren't swapped - they have one order, LSB first. Swapping
> only comes up because we people tend to have been trained to think MSB
> first.
> The hardware isn't.
>
> Figure 49-7 clearly shows the order of the fields in the packet payload.
> All fields are sent LSB first, a rule that applies to bit transmission
> through-out 802.3. This rule is shown for the data bytes in the transmission
>
> order figures.
>
> It would be good to add an explicit statement that the bits of each field
> are sent LSB first to probably at 49.2.4.2. I thought this was stated
> explicitly, but I can't find a spot where it is. This will need to be a
> recirculation ballot comment. (A bit of a problem since we didn't make any
> changes and that passed through first ballot without any comments, but a
> comment requesting an editorial clarification will be likely to get
> accepted.)
>
> Regards,
> Pat Thaler
>
> -----Original Message-----
> From: Tuan Hoang [mailto:tuanh@xxxxxxxxxxxx]
> Sent: Monday, January 21, 2002 11:58 AM
> To: stds-802-3-hssg@xxxxxxxx
> Subject: [802.3ae] Clause 49 - 64b/66b Control Codes Mapping and Bit
> Order
>
>
>
>
> All,
>
> I would appreciate your help to clarify a couple of 64b/66b coding
> convention questions. As I am referring to walker_1_700.pdf, and the
> example in his email of re: 64B/66B Control Codes Mapping & Bit Order, dated
> Oct/07/2000
>
> http://grouper.ieee.org/groups/802/3/10G_study/email/thrd38.html
>
> At the time, the discussion was around the swapping the order (LSB->MSB) of
> 7-bit 10GBASE-R control codes for tranmitted bit order. Since then,
> 10GBASE-R O codes were introduced, which consist of only 4 bits. My
> questions are:
>
> - Is the swapping of control codes are still at boundary of 7 bits as
> described in walker_1_700.pdf? Draft 4.0 seems to refer to this convention.
> - For the O-codes, should the swapping occur at 4 bit boundary as in the
> 7-bit control codes, or otherwise?
>
>
> For instant, two frames output from RS as followed:
>
> // RS output (Input to 64b/66b encoder)
>
> frame 1 - fd,1 fe,1 07,1 07,1 07,1 07,1 07,1 07,1 - T0 (EOP0) with error
> byte in byte #1 location
> frame 2 - 9c,1 00,0 00,0 00,0 5c,1 00,0 00,0 00,0 - Sequence Order set
> followed by Signal order set
>
> To be encoded by 64b/66b framer as:
>
> // For frame 1, should the internal 66 frame prior to scrambler would be as
> per walker_1_700.pdf?
>
> 01_11100001_01111000_00000000_00000000_00000000_00000000_00000000_00000000
> <--87--> <--1e-><--00--><--00--><--00--><--00--><--00--><--00--><--00->
>
>
> // For frame 2, should the swapping occur at the O-codes 4 bits boundary as
> followed?
>
> 01_10101010_00000000_00000000_00000000_00001111_00000000_00000000_00000000
> <--55--> <--00--> <--00--> <--00--> <0-><f-> <--00--> <--00--> <--00-->
>
> or
>
> // should the swapping occur at 8 bit boundary, as the two back-to-back O
> codes treated as data?
>
> 01_10101010_00000000_00000000_00000000_11110000_00000000_00000000_00000000
> <--55--> <--00--> <--00--> <--00--> <f-><0-> <--00--> <--00--> <--00-->
>
> Regards,
>
> Tuan