Disabling Native VLAN Configuration on Trunk mode
This chapter contains sample configurations to check the functionality to drop the untagged traffic by disabling the native VLAN by configuring disable-native-VLAN.
Topology
Native VLAN Topology
Configuration
SW1
 
| SW1#configure terminal | Enter configuration mode | 
| SW1(config)#bridge 1 protocol mstp | Create bridge | 
| SW1(config)#vlan database | Enter VLAN configuration mode | 
| SW1(config-vlan)#vlan 2-10 bridge 1 state enable | Create 2-10 vlans | 
| SW1(config-vlan)#exit | Exit VLAN configuration mode | 
| SW1(config)#interface xe21 | Enter interface configuration mode for xe21 | 
| SW1(config-if)#switchport | Configure switchport | 
| SW1(config-if)#bridge-group 1 | Associate interface with bridge-group 1 | 
| SW1(config-if)#switchport mode trunk | Configure port mode as trunk | 
| SW1(config-if)#switchport trunk allowed vlan all | Allow all the VLANs on the xe21 port | 
| SW1(config-if)#exit | Exit from interface mode | 
| SW1(config)#interface xe6 | Enter interface configuration mode for xe6 | 
| SW1(config-if)#switchport | Configure switchport | 
| SW1(config-if)#bridge-group 1 | Associate interface with bridge-group 1 | 
| SW1(config-if)#switchport mode trunk | Configure port mode as trunk | 
| SW1(config-if)#switchport trunk allowed vlan all | Allow all the VLANs on the xe6 port | 
| SW1(config-if)#exit | Exit from interface mode | 
| SW1(config)#commit | Commit the candidate configuration to the running configuration | 
SW2
 
| SW2#configure terminal | Enter configuration mode | 
| SW2(config)#bridge 1 protocol rstp vlan-bridge | Create bridge | 
| SW2(config)#vlan database | Enter VLAN configuration mode | 
| SW2(config-vlan)#vlan 2-10 bridge 1 state enable | Create 2-10 vlans | 
| SW2(config-vlan)#exit | Exit VLAN configuration mode | 
| SW2(config)#interface xe6 | Enter interface configuration mode for xe6 | 
| SW2(config-if)#switchport | Configure switchport | 
| SW2(config-if)#bridge-group 1 | Associate interface with bridge-group 1 | 
| SW2(config-if)#switchport mode trunk | Configure port mode as trunk | 
| SW2(config-if)#switchport trunk allowed vlan all | Allow all the VLANs on the xe6 port | 
| SW2(config-if)#exit | Exit from interface mode | 
| SW2(config)#interface xe13 | Enter interface configuration mode for xe13 | 
| SW2(config-if)#switchport | Configure switchport | 
| SW2(config-if)#bridge-group 1 | Associate interface with bridge-group 1 | 
| SW2(config-if)#switchport mode trunk | Configure port mode as trunk | 
| SW2(config-if)#switchport trunk allowed vlan all | Allow all the VLANs on the xe13 port | 
| SW2(config-if)#exit | Exit from interface mode | 
| SW2(config)#commit | Commit the candidate configuration to the running configuration | 
Validation
Sending untagged, VLAN-5 and VLAN-6 traffic from IXIA-1 to IXIA-2. In the show bridge output we can see all the MAC entries learnt for all the traffics.
In the show vlan brief output for default VLAN interface xe21 is having port type as untagged (u).
SW1#show bridge
bridge 1 is running on mstp
Ageout time is global and if something is configured for vxlan then it will be 
affected here also
 Bridge    CVLAN  SVLAN  BVLAN  Port        MAC Address       FWD   Time-out
 ---------+------+------+------+-----------+-----------------+-----+---------+
 1         1                    xe21       0010.9400.0001    1     300
 
SW1#show interface counters rate mbps
+-------------------+--------------+-------------+--------------+-------------+
|     Interface     |    Rx mbps   |    Rx pps   |    Tx mbps   |    Tx pps   |
+-------------------+--------------+-------------+--------------+-------------+
 xe21               621.21         606650        0.00           0
 xe6                0.00           0             621.21         606651
 
SW1#show vlan brief
Bridge  VLAN ID     Name         State   H/W Status      Member ports
                                                     (u)-Untagged, (t)-Tagged
======= ======= ================ ======= ========== ==========================
1       1       default          ACTIVE  Success    xe21(u) xe6(u)
1       2       VLAN0002         ACTIVE  Success    xe21(t) xe6(t)
1       3       VLAN0003         ACTIVE  Success    xe21(t) xe6(t)
1       4       VLAN0004         ACTIVE  Success    xe21(t) xe6(t)
1       5       VLAN0005         ACTIVE  Success    xe21(t) xe6(t)
1       6       VLAN0006         ACTIVE  Success    xe21(t) xe6(t)
1       7       VLAN0007         ACTIVE  Success    xe21(t) xe6(t)
1       8       VLAN0008         ACTIVE  Success    xe21(t) xe6(t)
1       9       VLAN0009         ACTIVE  Success    xe21(t) xe6(t)
1       10      VLAN0010         ACTIVE  Success    xe21(t) xe6(t)
Configuring Disable-Native-VLAN on Trunk mode
SW1
| SW1(config)#interface xe21 | Enter interface configuration mode for xe21 | 
| SW1(config-if)#switchport mode trunk disable-native-vlan | Configure disable native VLAN on trunk mode | 
| SW1(config-if)#exit | Exit from interface mode | 
| SW1(config)#commit | Commit the candidate configuration to the running configuration | 
 
Validation
After configuring disable-native-vlan, show vlan brief output we can see that xe21 interface is having port type as tagged (t). 
SW1#show bridge
bridge 1 is running on mstp
Ageout time is global and if something is configured for vxlan then it will be a
ffected here also
 Bridge    CVLAN  SVLAN  BVLAN  Port        MAC Address       FWD   Time-out
 ---------+------+------+------+-----------+-----------------+-----+---------+
 1         1                    xe21       0010.9400.0001    1     300
 
SW1SW1#show vlan brief
Bridge  VLAN ID     Name         State   H/W Status      Member ports
                                                     (u)-Untagged, (t)-Tagged
======= ======= ================ ======= ========== ==========================
1       1       default          ACTIVE  Success    xe21(t) xe6(u)
1       2       VLAN0002         ACTIVE  Success    xe21(t) xe6(t)
1       3       VLAN0003         ACTIVE  Success    xe21(t) xe6(t)
1       4       VLAN0004         ACTIVE  Success    xe21(t) xe6(t)
1       5       VLAN0005         ACTIVE  Success    xe21(t) xe6(t)
1       6       VLAN0006         ACTIVE  Success    xe21(t) xe6(t)
1       7       VLAN0007         ACTIVE  Success    xe21(t) xe6(t)
1       8       VLAN0008         ACTIVE  Success    xe21(t) xe6(t)
1       9       VLAN0009         ACTIVE  Success    xe21(t) xe6(t)
1       10      VLAN0010         ACTIVE  Success    xe21(t) xe6(t)
 
SW1#show interface counters rate mbps
+-------------------+--------------+-------------+--------------+-------------+
|     Interface     |    Rx mbps   |    Rx pps   |    Tx mbps   |    Tx pps   |
+-------------------+--------------+-------------+--------------+-------------+
 Xe21               864.88         844613        0.00           0
 Xe6               0.00           0             0.00           0
 
SW1#show interface counters drop-stats
Interface xe21
  Rx Policy Discards: 454522965
  Rx EGR Port Unavail: 454522967