Switch Port Types
There are multiple types of switch ports (per port):
Access - untagged packets are sent from this port, and the packets received are expected to be untagged. Tagged packets are dropped. Port PVID is assigned to the packet upon ingress. Access ports are normally used in switch-to-server connectivity.
Trunk - packets sent from this port are tagged, and the packets received are expected to be tagged. Untagged packets are dropped. There is an option to configure multiple VLANs on the trunk port. PVID cannot be configured on the port. Trunk port is suitable for switch-to-switch connectivity, or switch-to-server connectivity when multiple VLANs are used on the server port.
Hybrid - packets are sent tagged or untagged, the port expects both tagged and untagged packets. This mode combines Access and Trunk modes. There is an option to configure multiple VLANs on the hybrid port. PVID is configured on the port for untagged ingress packets.
A Port VLAN ID (PVID) is a default VLAN ID that is assigned to an access port to designate the virtual LAN segment to which this port is connected. The pvid places the port into the set of ports that are connected under the designated VLAN ID. Also, if a trunk port has not been configured with any VLAN memberships, the virtual switch's Port VLAN ID (pvid) becomes the default VLAN ID for the ports connection.
Link Types
The link type of VLAN can be divided into an access link and a trunk link.
Access link is part of only one VLAN, and normally is for end devices. Any device attached to an access link is unaware of a VLAN membership. An access-link connection can understand only standard Ethernet frames. Switches remove any VLAN information from the frame before it is sent to an access-link device.
Trunk link can carry traffic of multiple VLANs and is normally used to connect switches to other switches or to routers.
In Summary
Access ports:
Belong to one VLAN.
Commonly used to connect computer ports.
Trunk ports:
Allow multiple VLANs through.
Receive and send multiple VLAN packets.
Typically used for the connection between switches.
Hybrid ports:
Allow multiple VLANs through.
Receive and send multiple VLAN packets.
Used for connection between switches, or switch and compute
Port Behaviors
Here is an description how these ports perform in a system.
Access port
Strip the VLAN information in the packet and forward the packet directly.
Trunk port
Compare the PVID of the port and the VLAN information in the packet to be transmitted.
If they are the same, proceed to Step 3, otherwise, proceed to Step 4
Strip the VLAN information in the packet and forward the packet.
Forward the packet directly.
Hybrid port
Check the VLAN attributes on this port by running the command disp interface to se whether the VLAN attributes is "tagged" or "untagged"
If I is untagged, proceed to Step 3, if it is tagged, proceed to step 4.
Strip the VLAN information in the packet and forward the packet.
Forward the packet directly.