Implementing VLANs and Trunks Flashcards
For system use only. You cannot use these VLANs.
0, 4095 / Reserved
The Cisco default VLAN on a switch. You can use this VLAN, but cannot delete it. All interfaces belong to this VLAN, by default.
1 / Normal
Used for Ethernet VLANs.
2–1001 / Normal
For legacy reasons, these VLANs are used for Token Ring and Fiber Distributed Data Interface (FDDI) VLANs. You cannot delete VLANs 1002-1005.
1002–1005 / Normal
Used for Ethernet VLANs.
1006–4094 / Extended
Is a Cisco proprietary Layer 2 messaging protocol that maintains VLAN configuration consistency by managing the addition, deletion, and renaming of VLANs on a network-wide basis. It reduces administration overhead in a switched network. The switch supports VLANs in VTP client, server, and transparent modes.
VLAN Trunking Protocol (VTP)
A static-access port can belong to one VLAN and is manually assigned to that VLAN.
switchport mode access / Static-access
A trunk port is a member of all VLANs by default, including extended-range VLANs, but membership can be limited by configuring the allowed-VLAN list.
switchport mode trunk / Trunk
A voice VLAN port is an access port attached to a Cisco IP Phone, configured to use one VLAN for voice traffic and another VLAN for data traffic from a device attached to the phone.
switchport voice vlan vlan-id / Voice VLAN
Enables you to configure multiple ports at the same time.
interface range interfaces
Removes all settings from an interface, including VLAN association and membership mode.
default interface interface
Sets the interface to access mode.
switchport mode access
Set the voice VLAN to an interface. This action will instruct the Cisco IP phone to forward all voice traffic through the specified VLAN.
switchport voice vlan vlan-id
Command to display information on all configured VLANs. The command displays configured VLANs, their names, and the ports on the switch that are assigned to each VLAN.
show vlan
Command to display information about a particular VLAN. The example shows the output of the show vlan command for the “data” VLAN, which is VLAN 2.
show vlan id vlan_number or show vlan name vlan-name
Command, which displays one line for each VLAN with the VLAN name, status, and its ports.
show vlan brief
Is used by Cisco switches to automatically negotiate whether an interface used for interconnection between two switches should be put into access or trunk mode. When the interface is in trunk mode, DTP also negotiates trunk encapsulation.
Dynamic Trunking Protocol (DTP)
The interface will form a trunk only if it receives DTP messages to do so from the other side switch. An interface configured in dynamic auto mode does not generate DTP messages and only listens for incoming DTP messages.
dynamic auto
The interface will negotiate the mode automatically, and will actively try to convert the link to a trunk link. An interface configured in dynamic desirable mode generates DTP messages and listens for incoming DTP messages. If the port on the other side switch interface is capable to form a trunk, a trunk link will be formed.
dynamic desirable
Sets the native VLAN on the trunk to the specified VLAN number. Traffic from this VLAN is sent untagged. You must ensure that the switch on the other end of the trunk link is configured the same way.
switchport trunk native vlan vlan_number
Sets allowed VLANs on a trunk link. vlan_list is a sequence of VLAN numbers, separated with commas. The vlan_list cannot have spaces after commas.
switchport trunk allowed vlan vlan_list
Adds specified VLANs to the existing list of allowed VLANs on a trunk link. The vlan_list cannot have spaces after commas.
switchport trunk allowed vlan add vlan_list
Removes specified VLANs from the existing list of allowed VLANs on a trunk link. The vlan_list cannot have spaces after commas.
switchport trunk allowed vlan remove vlan_list
