2 ms·
> Ethernet through twisted-pair wiring only provides 80% of the listed bit-rate Actually, they already accommodated for this in the advertised speed. In other
by Unklejoe 7y ago
> Ethernet through twisted-pair wiring only provides 80% of the listed bit-rate
Actually, they already accommodated for this in the advertised speed.
In other words, a 1 GbE SerDes runs at 1.250 Gbit/s, so you end up with an actual 1 Gbit/s bandwidth.
The reason you don't actually hit 1 Gbit/s in practice is due to other overheads such as the interframe gaps, preambles, FCS, etc.
- smoyer 7y agoYou're absolutely correct ... it's been a long time since I was designing fiber transceivers but I should have remembered this. Ultimately efficiency is also affected by other layers of the protocol stack too (UDP versus TCP headers) which also explains why larger frames can be more efficient. In the early days of RTP and RTSP, there were many discussions about frame size, how it affected contention and prioritization and whether it actually helped to have super-frames if the intermediate networks were splitting and combining the frames anyway.
- blattimwind 7y ago> The reason you don't actually hit 1 Gbit/s in practice is due to other overheads such as the interframe gaps, preambles, FCS, etc. Actually Gigabit Ethernet is highly efficient; it can actually give you 98-99 % of line rate as the payload rate.