The IEEE 802.3, for Gigabit Ethernet, and supposedly the ANSI INCITS 263*, for the Regular and Fast Ethernet, have lists of signal quality requirements, which are generally tested using the so-called Ethernet Compliance Tests.
The dogma I was exposed to during my education, is that every serious Ethernet product needs to pass the compliance tests for the supported types of Ethernet it's using. Therefore, the tests are mandatory and must be done.
However, I never found an explanation why the tests are needed. I know that the regular EMI tests are needed because the agencies responsible for spectrum regulation (should) police the spectrum. For USB, the USB logos are copyrighted and compliance tests are among things needed to get the license to use the logos.
So my question is:
If my device passes EMC tests, and my Ethernet magnetics pass isolation tests, and my Ethernet port works with a crappy 100 m long cable,
is there some sort of Ethernet police which can come and get me, if I say that my device has Ethernet port, but I did not do the Ethernet compliance tests?
Background: General answers are very welcome, but I'm particularly interested in EU and USA regulations, especially those covering medical devices.
Best Answer
I think your starting point is wrong: you design a (medical/medical-related?) device featuring a communication (Ethernet/other) port, not an Ethernet (what?) featuring a device. Technically, from the standardization point of view, there is a sort (category) of electrical/electronic equipment having (among others) a communication ability.
First, you need to determine as tighter as possible the category your future device falls in, then, second, search for the requirements (common and/or particular) applicable/mandatory for the category (of the equipment) in the interested jurisdiction. In Europe, you could begin from IEC.
Returning to the category, ICS Number for the group "Medical Equipment" is 11.040, you can/need to certain the number deeper depending on your design, to find out the standards related to it. Try, for example, here.
After you (yourself, or consulting a specialist in that area, such as in Kema or other certification/test body) find the applicable requirements on (the category of) your equipment, such a standard very probably would be an umbrella one, i.e. it will contain references to (the requirements of) many/some other standards.
For example, it (very probably) will have (among others) a reference to EMC-related standards, including both susceptibility and emission (CISPR); EMC-related standards (typically) know nothing about Ehternet, but much about communication ports. Taste the IEC 60601 series (yes, each IEC/ISO/IEEE standard costs perceptibly).
Which tests? What are the requirements?
Nobody cares, what about the device in the scope of the requirements?
Nobody cares again before the requirements on the devices are clear, for particular Ethernet PHY there is the corresponding PICS, are your implementation satisfying it?
Typically and probably out of the context of a medical-related device, such a compliance could be declarative and not necessary approved by a specialized testing/certification body, well... such a police could be an angry client/community spreading out its "grounded, bad user experience" relating to your device, in a social network or forum in the internet - any is well indexed by Google and other search engines.