Re: Link Status thoughts
Pat (+ interested in working on a consensus proposal),
Thanks for condensing out the few remaining issues and shortening the
I'll be arriving Monday morning around 10:00 am and will be available
after the 802.3 meeting as well until dinner. The best way to reach me
there is by cell phone at 408-832-3957. I am very eager to work on a
> I don't see any need for a "listen before you speak" rule when
> coming out of reset. The concern if such a rule is put in is
> that one has to get into how long to listen before deciding the
> you are hearing nothing, etc. It's simpler to have the rule be
> "if you are getting good signal in send Idle, otherwise send RF."
I agree with your proposed rule.
> I agree with you that Remote Fault, Local Fault and Idle are
> a sufficient signalling set. I don't see a need for a Break Link
> meaning a signal to indicate the device is resetting or to reset
> the partner.
> The 8B/10B PCS Sequence protocol that you show below looks to me
> like an EMI problem. If you send randomized signal half the time
> and a repeating signal half the time, the spectum should only be
> about 3 dB down from sending repeating signal all the time. Randomized
> idle represented an improvement of about 20 dB over repeating
> sequence idles. Sending the PCS sequence protocol for too long
> would throw most of that gain away. There other ways to send the
> codes that would preserve the EMI gains.
We'll have to run a spectrum analysis of Sequence to be sure. I'm sure
its not as good as random AKR. However, I'm also sure that it's far
better than a packet of all 0's. We can probably come up with something
in between Sequence and Signal if need be to reduce EMI. However, the
lowest EMI can be achieved by using periodic Signal ala LSS.
Richard Taborek Sr. Phone: 408-845-6102
Chief Technology Officer Cell: 408-832-3957
nSerial Corporation Fax: 408-845-6114
2500-5 Augustine Dr. mailto:rtaborek@nSerial.com
Santa Clara, CA 95054 http://www.nSerial.com