DrScripttMay 20

I've been working with Ethernet for the better part of 30 years and I just now learned what a "runt Ethernet frame" is.

An Ethernet runt frame is a frame who's signal has degraded to the point that the start of frame bit isn't recognized and that a subsequent bit is incorrectly recognized as the start of frame bit. Thus yielding a recognized frame that is shorter than was originally transmitted.

My adaptation / interpretation of what William James Yeager wrote towards the end of § 3 ¶ 3 on page 7 of The Origins of the Stanford University SUMEX-AIM Router Technology - An Historical and Technical Overview.

Show threadDrScripttMay 20

This same paper confirms a suspicion as to why the Ethernet that we know and love is referred to as Etherne-2.

Ethernet-1, now often called research Ethernet, ran at 3 Mbps.

Ethernet-2, often stylized as Ethernet-II, ran at 10 Mbps.

Hence why we see Ethernet II in places like Wireshark.

#learningIsFun #Ethernet

Show threadRaven667May 20
@drscriptt it still kind of blows my mind that 1970s Ethernet was 10Mbps, thats still a useful amount of bandwidth even 50 years later
Show threadDrScriptt

@raven667 I think that Ethernet-1 / 3 Mbps was in `72 and Ethernet-2 / 10 Mbps was in `83.

So 10Base5 is 43 years old while 3Base6* is 54 years old.

*I think the first number is the speed in Mbps, band type (base or broad), and distance in meters divided by 100.

May 20 at 3:59amWeb