mac

88
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
Copper
cable port
Fiber cable
port
Fiber cable
port
Note:
1. 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.
2. If a combo port connects to another combo port, it is recommended for both parties to
use copper-forced or fiber-forced mode.
3. 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 (or copper) cable
port: Hardware is Gigabit-combo, active is fiber (or copper)
Example: Setting ports 1/21-24 to fiber-forced.
Switch(config)#interface ethernet 1/21-24
Switch(Config-Port-Range)#combo-forced-mode sfp-forced
3.1.3 clear counters interface
Command: clear counters interface [{ethernet <interface-list> | vlan <vlan-id> |
port-channel <port-channel-number> | <interface-name>}]
Function: Clears the statistics of the specified port.