Are there link pulses when autonegotiation on ethernet is off (force speed and duplex)


I read this. Is it correct that there is no link pulse when speed and duplex are forced (autonegotiation turned off)?

Best Answer

The answer to the question you referenced is correct... more precisely, it was correct until EEE (Energy Effective Ethernet) was invented. EEE employs the same fast link pulses to signal the link is up while the phys are in power-saving mode.

In 10BASE-T, FLPs are used to indicate the link is still on while there are no packet transmitted between the stations.

In 1000BASE-T, auto-negotiation is mandatory, you cannot turn it off at all, at least master-slave relation must be resolved from AN.

Also, it is preferable to not turn off AN even if you want to operate on an exact speed and duplex. You must select only that link ability (mode) and then start the AN process.

Therefore, my answer to this question is that the stated assumption is correct in some cases only, not in all.