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for copper cable port first;
sfp-forced
for fiber cable forces to use fiber cable port;
sfp-preferred-auto
for fiber cable port first.
Command mode: Interface Mode
Default:
The default setting for combo mode of combo ports is fiber cable port first.
Usage Guide:
The combo mode of combo ports and the port connection condition
determines the active port of the combo ports. A combo port consist of one fiber port and
a copper cable port. It should be noted that the speed-duplex command applies to the
copper cable port while the negotiation command applies to the fiber cable port, they
should not conflict. For combo ports, only one, a fiber cable port or a copper cable port,
can be active at a time, and only this port can send and receive data normally.
For the determination of the active port in a combo port, see the table below. The
headline row in the table indicates the combo mode of the combo port, while the first
column indicates the connection conditions of the combo port, in which “connected”
refers to a good connection of fiber cable port or copper cable port to the other devices.
Copper
forced
Copper
preferred
SFP forced
SFP
preferred
Fiber connected,
copper not connected
Copper
cable port
Fiber cable
port
Fiber cable
port
Fiber cable
port
Copper connected,
fiber not connected
Copper
cable port
Copper
cable port
Fiber cable
port
Copper
cable port
Both fiber and copper
are connected
Copper
cable port
Copper
cable port
Fiber cable
port
Fiber cable
port
Neither fiber nor
copper are connected
Copper
cable port
Fiber cable
port
Fiber cable
port
Fiber cable
port
Note:
&
Combo port is a conception involving the physical layer and the LLC sublayer of the
datalink layer. The status of a combo port will not affect any operation in the MAC
sublayer of the datalink layer and upper layers. If the bandwidth limit for a combo
port is 1Mbps, then this 1Mbps applies to the active port of this combo port,
regardless of the port type being copper or fiber.
&
If a combo port connects to another combo port, it is recommended for both parties
to use copper-forced or fiber-forced mode.
&
Run “show interface” under Admin Mode to check for the active port of a combo port
The following result indicates if the active port for a combo port is the fiber cable port
or copper cable port: Hardware is Gigabit-combo, active is fiber (copper).
Example:
setting ports 1/25 -28 to fiber-forced
Switch(Config)#interface ethernet 1/25-28
Switch(Config-Port-Range)#combo-forced-mode sfp-forced
