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broadcast domain, just as it happens with any normal switch. During data transfers, any VLAN
information or data from other VLANs is removed so the recipient has no information about them.
-
Trunk Mode :
Trunk Links (the link to/from trunk ports) is configured to carry packets for multiple VLANs.
These types of ports are usually found in connections between switches. These links require the
ability to carry packets from multiple VLANs because VLANs span over multiple switches.
-
Trunk Native Mode :
A Trunk-native port can carry untagged packets simultaneously with the 802.1Q tagged packets.
When you assign a default Access-VLAN to the trunk-native port, all untagged traffic travels on
the default Access-VLAN for the trunk-native port, and all untagged traffic is assumed to belong
to this Access-VLAN. This Access-VLAN is referred to as the native VLAN ID for a Trunk-
native Port. The native VLAN ID is the VLAN ID that carries untagged traffic on trunk-native
ports.
Example : PortX configuration
Configuration
Result
Trunk-VLAN = 10, 11, 12
Access-VLAN = 20
Mode = Access
PortX is an
Access Port
PortX’s
VID
is ignored
PortX’s
PVID
is 20
PortX sends
Untagged
packets (PortX takes away VLAN tag if the
PVID is 20)
PortX receives
Untagged
packets only
Trunk-VLAN = 10,11,12
Access-VLAN = 20
Mode = Trunk
PortX is a
Trunk Port
PortX’s
VID
is 10,11 and 12
PortX’s
PVID
is ignored
PortX sends and receives
Tagged
packets VID 10,11 and 12
Trunk-VLAN = 10,11,12
Access-VLAN = 20
Mode = Trunk-native
PortX is a
Trunk-native Port
PortX’s
VID
is 10,11 and 12
PortX’s
PVID
is 20
PortX sends and receives
Tagged
packets VID 10,11 and 12
PortX receives
Untagged
packets and add PVID 20
1.
Use “Interface” command to configure a group of ports’ 802.1q VLAN settings.
VLAN & Interface command
Parameter
Description
ICPE(config)# interface [port_list]
[port_list]
Enter several discontinuous port numbers
separated by commas or a range of ports
with a hyphen. For example:1,2
ICPE(config-if-PORT-PORT)# vlan
dot1q-vlan access-vlan [1-4094]
[1-4094]
Specify the selected ports’ Access-VLAN
ID (PVID).
ICPE(config-if-PORT-PORT)# vlan
dot1q-vlan trunk-vlan [1-4094]
[1-4094]
Specify the selected ports’ Trunk-VLAN
ID (VID).
ICPE(config-if-PORT-PORT)# vlan
dot1q-vlan mode access
Set the selected ports to access mode
(untagged).
ICPE(config-if-PORT-PORT)# vlan
dot1q-vlan mode trunk
Set the selected ports to trunk mode
(tagged).