Kevmcs

Ethernet

I accidentally reverted your contribution to Ethernet when I hit the TW rollback button by mistake. But then I noticed you hadn't said why you changed the number, so rather than fix it, I'll leave it to you to re-do it with a comment if it's right. Dicklyon (talk) 20:48, 27 January 2008 (UTC)

I updated the change with comment, start of frame should be 10101011 instead of 11010101. please see Start_Frame_Delimiter. — Preceding unsigned comment added by Kevmcs (talk • contribs)

Thanks. But you may have uncovered a notational ambiguity; take a look at this Agilent PDF. It says "The frames are transmitted from left to right, least significant bit first." and "11010101 for the SFD." I think this is correct and that the "11" comes last in time order, which means it's in the MSBs of the octet. Maybe you can verify and clarify. Dicklyon (talk) 21:24, 27 January 2008 (UTC)

I think we are saying the same thing, what if it stated 010101011 is the bit pattern as the SFD must end with 11.

I just verified in "Computer Networking A Top-Down Approach" by James Kurose, and Keith W Ross, they state 10101011 is the last byte of the 8 byte preamble page 473, sixth edition. I think this can also be found

[1] [2][3] state that 11 will be sent last.

looks like 802.3 IEEE standard is available for download free IEEE 802.3 part 1 page 50.

"The SFD field is the sequence 10101011. It immediately follows the preamble pattern and indicates the start of a frame."

also page 105 states

"The preamble pattern is: 10101010 10101010 10101010 10101010 10101010 10101010 10101010 The bits are transmitted in order, from left to right"

It may be best to state the byte pattern in the table

We've got it both ways, with clear explanation and source now. OK? Dicklyon (talk) 00:05, 28 January 2008 (UTC)

We really need the 11 listed and sourced to the IEEE 802.3 spec. It really should be in the table with explanation on LSB MSB above.

The bit pattern end with 11 is important to display as last 2 bits of the eight byte are always consecutive 11. Even if the preamble had been corrupted, the following destination address can be identified correctly. The table needs to reflect that the last two bits are 11. The authoritative source is 802.3 IEEE standard, and we need to source it and table should reflect it Kevmcs (talk) 23:56, 27 January 2008 (UTC)