[c-nsp] loop guard still useful?

Lee ler762 at gmail.com
Mon Jan 18 15:57:38 EST 2016

On 1/18/16, Saku Ytti <saku at ytti.fi> wrote:
> On 18 January 2016 at 21:22, Lee <ler762 at gmail.com> wrote:
>> so apparently 100Mb fiber doesn't have that problem any more.  I don't
>> think 1 or 10Gb fiber ever did..
> I believe if you implement autonego, you have to implement RFI. But
> I'm not 100% sure about that.
> IEEE 802.3 standard isn't exactly easiest standard to read. But there
> are quite many surprising goodies in autonego which are usually not
> known, not just RFI. Autonego can assert when link is configured
> operationally down, meaning far-end could produce syslog information
> about link going down, because far end was configured down, which
> would help lot with troubleshooting, when you can know if far-side is
> intentionally down or not.
> My understanding of reading hardware specs is that this feature is
> even supported in typical PHY, however I've NEVER seen software using
> this feature.
> I'd love recommendation on good, modern book about 802.3, with
> irrelevant bits not addressed, relevant bit discussed and practical
> view offered on how things are actually implemented in modern, common
> hardware. So far any book I've read, does not even discuss autonego in
> satisfactory detail, and I fear what else am I missing due to my
> unwillingness to weed through 802.3.

If you get any off-list replies please post a summary.  I haven't seen
any good books about ethernet in ages, but I haven't really been
looking either.


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