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Catalyst 3560 Switch Software Configuration Guide
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Chapter 10 Configuring Interface Characteristics
Configuring Ethernet Interfaces
Configuring Ethernet Interfaces
These sections describe the default interface configuration and the optional features that you can
configure on most physical interfaces:
•
Default Ethernet Interface Configuration, page 10-11
•
Configuring Interface Speed and Duplex Mode, page 10-12
•
Configuring IEEE 802.3X Flow Control, page 10-14
•
Configuring Auto-MDIX on an Interface, page 10-15
•
Configuring Power over Ethernet on an Interface, page 10-16
•
Adding a Description for an Interface, page 10-18
Default Ethernet Interface Configuration
Table 10-1
shows the Ethernet interface default configuration, including some features that apply only
to Layer 2 interfaces. For more details on the VLAN parameters listed in the table, see
Chapter 12,
“Configuring VLANs.”
For details on controlling traffic to the port, see
Chapter 20, “Configuring
Port-Based Traffic Control.”
Note
To configure Layer 2 parameters, if the interface is in Layer 3 mode, you must enter the switchport
interface configuration command without any parameters to put the interface into Layer 2 mode. This
shuts down the interface and then re-enables it, which might generate messages on the device to which
the interface is connected. Furthermore, when you use this command to put the interface into Layer 2
mode, you are deleting any Layer 3 characteristics configured on the interface.
Table 10-1
Default Layer 2 Ethernet Interface Configuration
Feature
Default Setting
Operating mode
Layer 2 or switching mode (switchport command).
Allowed VLAN range
VLANs 1 – 4094.
Default VLAN (for access ports)
VLAN 1 (Layer 2 interfaces only).
Native VLAN (for 802.1Q trunks) VLAN 1 (Layer 2 interfaces only).
VLAN trunking
Switchport mode dynamic auto (supports DTP)
(Layer 2 interfaces only).
Port enable state
All ports are enabled.
Port description
None defined.
Speed
Autonegotiate.
Duplex mode
Autonegotiate.
Flow control
Flow control is set to receive: off. It is always off for sent packets.
EtherChannel (PAgP)
Disabled on all Ethernet ports. See
Chapter 29, “Configuring
EtherChannels.”
Port blocking (unknown multicast
and unknown unicast traffic)
Disabled (not blocked) (Layer 2 interfaces only). See the
“Configuring Port Blocking” section on page 20-6
.