3. Minimum Frame Length in Ethernet
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Published 2021-08-23
Minimum package length;
Maximum cable length;
Relationship between Speed of Light, Cable Lenght, Frame Size, and Cock Cycle Interval.
Speed of Light: metres per second: 299,792,458.
In order to avoid a collision, "what you want to achieve is to send data so that it occupies the entire shared medium."
For example; for a 100MBit/s Ethernet card - that will send 100 million bits per second, for sending 1 bit it would need 10 nanoseconds of time (0.00000001sec). The data (bits) spreads at the speed of light (the speed of light is approximately 300 million m/s). Therefore, for a "100MBit/s Ethernet within 1 clock cycle, the signal would have traveled approx 3 meters... to occupy the entire network the medium should be shorter than 3 meters."
Cables have to be 100 meters and longer. The minimum data/payload of the Ethernet frame has to be at least 46 bytes even if you want to send only 1 bit of data you still have to have a payload of at least 46 bytes. Hence, the minimum Ethernet frame size of 64 bytes (512 bits) can achieve a distance of 1500m (512 bits * 3 meters).
In computers, the clock cycle is the amount of time between two pulses of an oscillator. It is a single increment of the central processing unit (CPU) clock during which the smallest unit of processor activity is carried out.
en.wikipedia.org/wiki/Ethernet_frame#Runt_frames