No-default-native-vlan trunk mode – Brocade Network OS Administrator’s Guide v4.1.1 User Manual
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• VLAN 1 cannot be used as a classification CTAG.
• Ingress and egress tagging behavior is controlled by the interface-level configuration, not by the
global configuration.
The following summarizes the native service VF (VLAN ID > 4095) classifications that can or cannot
be supported with the respective commands.
Service VF native VLAN classifications
TABLE 64
Ingress allowed frame type
Egress
tagging:
Untagged
only
Egress
tagging:
Tagged only
CLI
None
N/A
N/A
None (tagged native VLAN is always
forwarded)
Untagged only
No
N/A
switchport trunk native vlan vid,
no switchport trunk tag native-vlan
Tagged only
N/A
Yes
switchport trunk native vlan vid ctag cvid,
switchport trunk tag native-vlan
Untagged and tagged
Yes
No
switchport trunk native vlan vid ctag cvid,
no switchport trunk tag native-vlan
The following illustrates configurations that are valid or invalid in regular trunk mode.
(config)# int te 5/0/1
(config-if-te-5/0/1)# switchport mode trunk
(config-if-te-5/0/1)# switchport trunk native-vlan-untagged 6000
ERROR: invalid command
# VLAN 1 cannot be used as a classification tag
(config-if-te-5/01)# switchport trunk native-vlan 6000 ctag 1
ERROR: default vlan 1 cannot be classified to a virtual fabric
# CTAG not used elsewhere can be used
(config-if-te-5/01)# switchport trunk native-vlan 6000 ctag 2
# Service VF classification without C-TAG is permitted if ingress frame type allows
untagged packet
# at that interface. Global mode tagging control does not apply to a service VF.
(config-if-te-5/01)# switchport trunk native-vlan 7000
ERROR: interface is not configured to accept untagged packet
(config-if-te-5/01)# no switchport trunk tag native-vlan
(config-if-te-5/01)# switchport trunk native-vlan 7000
No-default-native-VLAN trunk mode
Another set of native VLAN classifications for service and transport VFs is available in trunk mode
without the implicit creation of a default VLAN. The purpose of this trunk mode is to provide flexibility
that is not available in default VLAN trunk mode and do the following:
• Provide a raw Layer 2 switchport with no VLAN configuration.
• Allow native VLAN configuration when it is needed.
• Allow the mapping of a native VLAN to a service or transport VF.
• Allow the independent specification of ingress acceptable frame type and egress tagging options.
This trunk mode differs from the default-VLAN trunk mode in the following ways:
No-default-native-VLAN trunk mode
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Network OS Administrator’s Guide
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