Layer 2 Interface Modes; Default Layer 2 Ethernet Interface Configuration - Cisco 4500M Software Manual

Default Layer 2 Ethernet Interface Configuration

Layer 2 Interface Modes

Table 12-2
Table 12-2 Layer 2 Interface Modes
Mode
switchport mode access
switchport mode dynamic
desirable
switchport mode dynamic auto
switchport mode trunk
switchport nonegotiate
DTP is a point-to-point protocol. However, some internetworking devices might forward DTP frames
Note
improperly. To avoid this problem, ensure that interfaces connected to devices that do not support DTP
are configured with the access keyword if you do not intend to trunk across those links. To enable
trunking to a device that does not support DTP, use the nonegotiate keyword to cause the interface to
become a trunk without generating DTP frames.
Default Layer 2 Ethernet Interface Configuration
Table 12-3
Table 12-3 Layer 2 Ethernet Interface Default Configuration
Feature
Interface mode
Trunk encapsulation
Allowed VLAN range
VLAN range eligible for pruning VLANs 2–1001
Default VLAN (for access ports) VLAN 1
Software Configuration Guide—Release 12.2(25)EW
12-4
lists the Layer 2 interface modes and describes how they function on Ethernet interfaces.
Purpose
Puts the interface into permanent nontrunking mode and
negotiates to convert the link into a nontrunking link. The
interface becomes a nontrunk interface even if the neighboring
interface does not change.
Makes the interface actively attempt to convert the link to a
trunking link. The interface becomes a trunk interface if the
neighboring interface is set to trunk, desirable, or auto mode.
This is the default mode for all Ethernet interfaces.
Makes the interface convert the link to a trunking link if the
neighboring interface is set to trunk or desirable mode. This is
the default mode for all Ethernet interfaces.
Puts the interface into permanent trunking mode and negotiates to
convert the link into a trunking link. The interface becomes a
trunk interface even if the neighboring interface does not change.
Puts the interface into permanent trunking mode but prevents the
interface from generating DTP frames. You must configure the
neighboring interface manually as a trunk interface to establish a
trunking link.
shows the Layer 2 Ethernet interface default configuration.
Default Value
switchport mode dynamic auto
switchport trunk encapsulation negotiate
VLANs 1–1005
Chapter 12 Configuring Layer 2 Ethernet Interfaces
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