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Catalyst 3750-E and 3560-E Switch Software Configuration Guide
OL-9775-02
Chapter 11 Configuring Interface Characteristics
Configuring Ethernet Interfaces
Default Ethernet Interface Configuration
Table 11-3 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 13,
“Configuring VLANs.” For details on controlling traffic to the port, see Chapter 26, “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. When you put an interface that is in Layer 3 mode into Layer 2 mode, the
previous configuration information related to the affected interface might be lost, and the interface is
returned to its default configuration.
Table 11-3 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 IEEE 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. (Not supported on the 10-Gigabit interfaces.)
Duplex mode Autonegotiate. (Not supported on the 10-Gigabit interfaces.)
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 37, “Configuring
EtherChannels and Link-State Tracking.”
Port blocking (unknown multicast
and unknown unicast traffic)
Disabled (not blocked) (Layer 2 interfaces only). See the
“Configuring Port Blocking” section on page 26-6.
Broadcast, multicast, and unicast
storm control
Disabled. See the “Default Storm Control Configuration” section
on page 26-3.
Protected port Disabled (Layer 2 interfaces only). See the “Configuring
Protected Ports” section on page 26-5.
Port security Disabled (Layer 2 interfaces only). See the “Default Port Security
Configuration” section on page 26-10.
Port Fast Disabled. See the “Default Optional Spanning-Tree
Configuration” section on page 20-12.