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A comment on Designing a Low Latency 10G Ethernet Core (2023). Parent comment

Re:Designing a Low Latency 10G Ethernet Core (2023) by ongy on Thursday October 09, 2025 @04:34AM (#45525046)
why do you assume the full ethernet header?

IIRC. cut-through only needs the first 6 bytes. Since it only needs the destination address for the port lookup.

Potentially the first bit, on broadcast.

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Re:Designing a Low Latency 10G Ethernet Core (2023) by rasz on Thursday October 09, 2025 @05:41AM (#45525479)
Because you might want VLAN. Plus you cant just start blasting reply without a preamble, so its still 14 bytes after receiving just the dest MAC. Then you get potential IFG, FEC, scrambling, it all adds up, no way any switch can do 4ns without heavy lawyer talk in the small print.
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