Re: [STDS-802-3-400G] Query in 802.3bs Draft 1.0 : Clause 119

[Mark Gustlin <mark.gustlin@xxxxxxxxxx>]

Prashant,

 

It is due to the scrambler location.

Please feel free to submit comments against draft 1.1 when that comes out if you believe corrections needed.

 

Thanks, Mark Gustlin

 

From: Dixit, Prashant [mailto:Prashant_Dixit@xxxxxxxxxx]
Sent: Friday, November 20, 2015 3:52 AM
To: STDS-802-3-400G@xxxxxxxxxxxxxxxxx
Subject: [STDS-802-3-400G] Query in 802.3bs Draft 1.0 : Clause 119

 

Hi All,

 

In 802.3bs, Clause 119, Section 119.2.5.6 256B/257B to 64B/66B transcoder, where reverse transcoding of one 257-bit block into 4 - 66 bits blocks is defined.

 

It seems there are couple of discrepancies in that algorithm :

 

1.       In sub-point e2) g<3:0> has been used but it is not described how to generate g<3:0>.

2.       Also we have observed that Tx transcoder function (4 - 66bits blocks to 1 - 257bits) defined in 802.3bj specs, Section 91.5.2.5 (RS-FEC layer) is exactly the same as Tx transcoder function defined in 802.3bs Section 119.2.4.2. But the RX reverse transcoder function (1 - 257 bits block to 4 - 66 bits blocks) defined in 802.3bs, Section 119.2.5.6 is quite different from the same function defined in 802.3bj, Section 91.5.2.5.  Is it intentional ?

If it is intentional and correct why Rx algorithms are different if Tx algorithm are same. Is it due to the scrambler position which is different in both the versions ?

 

Please correct me if I missed something or advice accordingly.

 

Thanks and regards

Prashant