Second attempt to get this
sent to the email list
Folks,
On reviewing the Yahoo mailing list archive I saw an email asking why
the compatibility with 802 criterion failed to get the necessary 75%
approval in the 802.3 closing plenary session. In my view there are two
reasons for this:
1)
It was stated during the debate in the closing plenary by a study group
member that no changes to the MAC or PHY may be necessary. If that is
the case then what is the point of doing an 802.3 project? You need to
give the 802.3 working group some idea of what it is that you want to
do.
2)
You failed to convince 802.1 that what you are proposing is compatible
with their switching specs. The tutorial gave the impression that the
purpose of the task force would be to standardize a mooted Firewire
switch architecture in 802.1. This switch architecture requires a
separate queue for RE traffic and is required to deliver frames at
precise time intervals. Predictably this did not go down well in 802.1
and the 802.3 working group took notice of this.
I also have the following observations to make
i)
To see RE through as an 802.3 project you need to engage with the wider
802.3 working group. Using a Yahoo mailing list rather than this one
does not help. If you want to know why people voted against the
compatibility criterion ask on this mailing list. The vote to set up
the study group was 41 to 7 so there is support for a task force and
making changes to the 802.3 spec for RE. Don't squander this good will.
ii)
You need a chair who is experienced in 802.3 policy and procedures.
iii)
You need to come up with a quantitative requirement for jitter and
relative latency and justify it. I saw the figure of 10us mentioned on
the Yahoo mailing list. This is ridiculously tight. An 802.3 voter who
is experienced in VOIP pointed out to me that even 1ms is too tight
when you consider that sound only travels one foot in a millisecond.
Once you have this requirement nailed a lot else will fall into place.
iv)
The sort of thing that would make sense for a task force would be to
develop a mechanism for measuring link delay using MAC control frames
so that time stamp information could be accurately interpreted. This is
within the scope of 802.3 and clearly relevant to what you are trying
to achieve with residential Ethernet.
Arthur.