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Voss Access/Trunk Port configuration

Voss Access/Trunk Port configuration

New Contributor II

Hi Support,

I have gone through the extreme documentation but still the configuration between access port and trunk port in VOSS cli is really confusing to me.

For example:

vlan members 23 1/7 portmember I think refers to trunk port configuration on port 1/7

This article:   Further adds to the configuration.

In the documentation, the there is also this Example:


For untagging the port in a VLAN:
#vlan create 12 type port-mstprstp 0 (Create VLAN and type)
#vlan mem 2/2 12 (Add it as a member)
#int gig 2/2
#encapsulation dot1q
#default-vlan-id port 2/2 12 (Specifying that vlan 12 is the default untagged vlan OR Native VLAN)
#untag-port-default-vlan (Specifying that vlan 12 will be used as untagged)


Kindly clarify with clear examples of the differences between access port and trunk port interface configuration in voss.

Thank you all!




Are we using VOSS commands here???

The only way to configure a trunk or tagged port or an access or untagged port in VOSS is

VOSS_SWITCH-01:1(config-if)#interface gigabitEthernet 1/25
VOSS_SWITCH-01:1(config-if)#encapsulation dot1q
VOSS_SWITCH-01:1(config-if)#no encapsulation dot1q

Switchport, I think, is a Cisco command.

In VOSS (and also BOSS ERS), the default-vlan-id is always configured.
- When it is an access port then the default-vlan-id = automatically the to that port assigned vlan id and this cannot be changed.
- When it is a tagged or trunk port the default-vlan-id is also configured on the port but it has no meaning or effect unless untag-port-default-vlan is configured, then packets originating from the default-vlan-id are send out untagged (often used to tagg packets for an IP phone and untag packets for a PC connected behind the IP phone).

As an example I configured vlans 3000 3001 and 4000 on port 1/25 and configured vlan 4000 to be untaged.

SMC-MCN-003-01:1#show interfaces gigabitEthernet vlan 1/25
Command Execution Time: Tue May 28 21:48:55 2024 CEST

Port Vlans
1/25  enable   false    false      4000    3000,3001,4000  normal  enable   P        4000

P=Protocol enabled.


View solution in original post




We are talking VOSS in this discussion

It is and will always be confusing people when talking about TRUNK.
First of all, what is a TRUNK?, a TRUNK is a group/collection/... of things.

  • For Cisco oriented people a TRUNK is a group of ports (LAG link aggregation).
  • For some others (EXTREME is one of them) they talk TRUNK in regards to a group of vlan's assigned to a port or an MLT (Multi Link Trunk).

So for some people a TRUNK is a group of vlan's, for others it is a group of ports.
First of all when starting discussing TRUNK's, agree in what you understand a TRUNK is.


  • The correct command to add a vlan to a port is "vlan members add 1111 1/25", so vlan first the the port.
  • The correct command to add a vlan to an MLT is "mlt 111 vlan 1111".
    In the configuration it will be shown as port and MLT member, see below.

vlan create 1111 name "vlan_1111" type port-mstprstp 0
vlan mlt 1111 111
vlan members 1111 1/11 portmember

  • On an untagged or access port vlan info is removed from the outgoing packets.
  • On a tagged port, all vlan's can be tagged or all vlan's can be tagged except one which is untagged.


New Contributor II

Hi @WillyHe 

Thanks for your response! Your explanation was heading somewhere until you mentioned MLT which is something am still grasping. So it threw me off your point.  Kindly use straight forward example of regular port interface. Otherwise, thanks for shedding light on it!👍



In VOSS, and MLT is equal to etherchannel or LACP static configuration, it groups (trunks 😊) multiple ports in a Link-Aggregation-Group or Multi-Link-Trunk (so here we also talk about "trunk").

To have vlan's tagged/trunked on an MLT, this is enable/disabled on the MLT interface, not on the MLT member ports, the MLT is controlling the ports, at least for a "static" MLT configuration.
When LACP is enabled on an MLT then enable/disable tagging is done on port level.

Every switch OS has his way of doing things, most are similar but there are always (small 🙂) differences.

hope it helps clarifying

New Contributor

To @Isaac001 ,

The confusion regarding access and trunk ports in Voss is understandable. Here's a breakdown to clarify the differences with configuration examples.
An access port allows traffic for a single VLAN (untagged traffic). Used for devices that only need to communicate on one network (e.g., computers, printers).
A trunk port carries traffic for multiple VLANs (tagged traffic). Used for devices that need to communicate with multiple networks (e.g., routers, switches in different VLANs).

# Create VLAN 10
vlan create 10 type port-mstp-rstp 0

# Add interface GigabitEthernet 1/1 as a member of VLAN 10
vlan mem 1/1 10

# Configure GigabitEthernet 1/1 as an access port
interface GigabitEthernet 1/1
  no switchport mode trunk       # Don't configure as trunk mode
  switchport mode access          # Set mode to access
  default-vlan 10                # Set default VLAN to 10 (untagged traffic)

This configuration creates VLAN 10 and adds GigabitEthernet 1/1 as a member. The interface is then configured as an access port with default-vlan 10, specifying that all untagged traffic on this port belongs to VLAN 10.

# Create VLANs 20 and 30
vlan create 20 type port-mstp-rstp 0
vlan create 30 type port-mstp-rstp 0

# Configure GigabitEthernet 2/2 as a trunk port
interface GigabitEthernet 2/2
  switchport mode trunk          # Set mode to trunk
  vlan member 20 30              # Add VLANs 20 and 30 as members (tagged traffic)

This configuration creates VLANs 20 and 30. GigabitEthernet 2/2 is configured as a trunk port with switchport mode trunk. Then, VLANs 20 and 30 are explicitly added as members using vlan member, allowing tagged traffic for both VLANs on this port.

The main difference lies in the switchport mode and default-vlan commands.

Access Port no switchport mode trunk, default-vlan <vlan_id> (untagged traffic).
Trunk Port switchport mode trunk, vlan member <vlan_id1> <vlan_id2>... (tagged traffic).

Best Regards,