Hello everyone!
Today, I will continue to write about the basic principle of VLAN technology. This is the fourth article. Now, I will explain the ports and link type of VLAN.
The access port is only part of one VLAN, and trunk and hybrid ports are part of the multiple VLAN. The default port is 1, and we can not delete it. At the start configuration, all default ports are part of VLAN 1.
Figure. 1. Link type of VLAN
Access port and link
The access link is a link between switch and host (as we can see in figure 1). All hosts in the same VLAN, have access links with switches, and communication with frames that are not marked. All ethernet ports in the switch, in the same VLAN, are access ports.
The main features of the access port are:
Default VLAN is 1.
Communication between devices in the same VLAN is with untagged frames.
Discard all non-Access VLAN frames.
In figure 2, we can see the access link configuration on the switch.
Figure 2. Access link configuration
Trunk port and link
A trunk link is a link between two or more VLANs, it can belong to multiple VLANs. This link allows to send and receive tagged frames from different VLANs. A network administrator uses trunk links for interconnection between switches and for connection between router and switch. These Ethernet ports, ports for connection between different VLANs, are trunk ports. Communication between different VLANs requires tagging all frames.
The main features of the trunk port are:
A trunk port can be a member of all VLANs (1-4095),
A trunk port forwards multiple VLAN frames, and
A trunk port can allow all or only certain VLANs to communicate with each other.
Figure 3. shows us the trunk-link configuration.
Figure 3. Trunk link configuration
Hybrid port
The hybrid port is a port for connection to either hosts or switches. This port can receive and send multiple VLAN packets. It can belong to multiple VLANs.
On the one switch, we can have a trunk port or hybrid port. The difference between these ports is that the hybrid port can allow untagged frames from many VLANs. On the other side, the trunk port allows only the default VLAN packet to be untagged. Finally, there cannot be a trunk and a hybrid port on the same switch.
Continued in the next article.
Thank you!
For more information, please click:
Basic principles of VLAN technology (1)
Basic principles of VLAN technology (2)
Basic principles of VLAN technology (3)
