Hi,
2.3µs is a typical delay for a 10GBASE-T connection. But fiber or SFP+ DAC connections should be faster: switches are typically in the range of ~500ns to 1µs.But you'll find that this small difference in latency induced by the switch will be quite irrelevant in the grand scheme of things when using the Linux network stack...
2018-03-21 12:16 GMT+01:00 Willem Jan Withagen <wjw@xxxxxxxxxxx>:
Hi,
I just ran into this table for a 10G Netgear switch we use:
Fiberdelays:
10 Gbps vezelvertraging (64 bytepakketten): 1.827 µs
10 Gbps vezelvertraging (512 bytepakketten): 1.919 µs
10 Gbps vezelvertraging (1024 bytepakketten): 1.971 µs
10 Gbps vezelvertraging (1518 bytepakketten): 1.905 µs
Copperdelays:
10 Gbps kopervertraging (64 bytepakketten): 2.728 µs
10 Gbps kopervertraging (512 bytepakketten): 2.85 µs
10 Gbps kopervertraging (1024 bytepakketten): 2.904 µs
10 Gbps kopervertraging (1518 bytepakketten): 2.841 µs
Fiberdelays:
1 Gbps vezelvertraging (64 bytepakketten) 2.289 µs
1 Gbps vezelvertraging (512 bytepakketten) 2.393 µs
1 Gbps vezelvertraging (1024 bytepakketten) 2.423 µs
1 Gbps vezelvertraging (1518 bytepakketten) 2.379 µs
Copperdelays:
1 Gbps kopervertraging (64 bytepakketten) 2.707 µs
1 Gbps kopervertraging (512 bytepakketten) 2.821 µs
1 Gbps kopervertraging (1024 bytepakketten) 2.866 µs
1 Gbps kopervertraging (1518 bytepakketten) 2.826 µs
So the difference is serious: 900ns on a total of 1900ns for a 10G pakket.
Other strange thing is that 1K packets are slower than 1518 bytes.
So that might warrant connecting boxes preferably with optics
instead of CAT cableing if you are trying to squeeze the max out of a setup.
Sad thing is that they do not report for jumbo frames, and doing these
measurements your self is not easy...
--WjW
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