Dell N1100-ON Reference Manual page 418

supporting are advertised. Not all ports support all speeds, even if they are
available in the command. Entering an unsupported speed will produce the
following error message An invalid interface has been used
for this function.
Fiber ports (other than 1000Base-X) do not support auto-negotiation and
therefore require the operator to enter the speed command with the desired
operating bandwidth. The link partner must be similarly configured.
SFP+/QSFP fiber ports do not support auto-negotiation, although it may be
enabled when using Direct Attach Copper cables if the link partner also
supports auto-negotiation. 1G SFP fiber ports should have auto-negotiation
enabled. SFP transceivers in an SFP+ port should have auto-negotiation
enabled. The default behavior is to enable auto-negotiation when an SFP
transceiver is inserted into an SFP+ port, unless a fixed speed is configured.
Likewise, SFP+ ports connected via copper Direct Attach Cables should have
auto-negotiation enabled if the link partner is also capable of performing
auto-negotiation. If the link partner cannot perform auto-negotiation, then a
fixed speed must be utilized. In all cases, the link partners need compatible
settings, e.g., both sides must be set to use auto-negotiation or a fixed speed.
In the case of a fixed speed link, both sides must be set to the same speed.
Failure to set both sides of a link to the same speed/duplex values (auto-
negotiation disabled) or compatible speed/duplex values (auto-negotiation
enabled) may give a false link-up indication when configured or when the link
is brought up (no shut). Setting one end of a link to auto-negotiate and the
link partner to a fixed speed is not supported.
Example
The following example configures Gigabit Ethernet port 1/0/5 to advertise
100-Mbps operation only via auto-negotiation.
console(config)#interface gigabitethernet 1/0/5
console(config-if)#speed auto 100
Command History
The speed 10000 syntax was introduced in the 6.3.6 release.
The 2500 and 5000 speeds were introduced in the 6.3.5 release. The
description was updated in the 6.4 release.
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Layer 2 Switching Commands