Ethernet names...

[Grant Taylor]

On 10/04/2018 11:07 AM, Eric Smith via cctalk wrote:
> The Ethernet I and II standards are available from Bitsavers:
>      http://bitsavers.trailing-edge.com/pdf/xerox/ethernet/

Cool.

> From the preface of _The Ethernet_ Version 2.0: Version 2.0 of the 
> Ethernet specification reflects the experience of the three corporations 
> in designing equipment to the Version 1.0 specification.  Version 2.0 
> includes network management functions and better defines the details 
> of the physical channel signalling.

Okay.  Intriguing.

> Version 2.0 is upward compatible with Version 1.0. Equipment designed 
> to the two specifications is interoperable.

My brain is having some trouble unpacking and understanding "upward 
compatible".  -  I always think that it should be "new version is 
/downward/ compatible with the old version" or "the old version is 
/upward/ compatible with the new version".

It's also stumbling on "the two specifications is interoperable".  Is 
that "the (version) two specification is interoperable (with the version 
one specification)" or "the two specification(s) /are/ interoperable"? 
This might not make much difference.  But my brain trips on are they 
truly 100% interoperable (as in extra fields in version 2 that version 1 
ignores) or is it a case of version 1 only understand version 1 and 
version 2 is able to pretend to be version 1 when talking to version 1?

Sort of like a crude diagram:

v1  <--->| v2
v1 |<--->| v2
v1 |<--->  v2

Which of the three is it?

I'll have to check out the documentation on Bitsavers.  Thank you for 
the link.



-- 
Grant. . . .
unix || die