What Is A Trunk Port And Why Do I Need One?
This article assumes that the reader has a fundamental knowledge computer networking and of VLAN segmentation. We will not cover those topics for the sake of brevity.
Please search for a course online if you need to cover computer networking basics, we will not cover that here.
Read here if you need a refresh on VLAN fundamentals: https://www.redhat.com/sysadmin/vlans-sysadmins-basics
In short, a trunk port is a port on a switch or router that is configured to carry traffic from multiple VLANs. This is compared to an access port, which allows access to only one VLAN. It is increasingly common to see VLAN segmentation in the fuel center environment for the purpose of providing security for consumer payment data. Especially as other types of data, such as advertisement media, are starting to get pushed to fuel dispensers. AvaLAN’s fuel center equipment, including our wireless EMV kit, can provide this segmentation in the pump using the five-port switch integrated into each AvaLAN in-dispenser unit. This is currently most common on Wayne’s Anthem dispenser platform, but we expect it to become the norm across other dispenser lines soon.
Because of this, the AvaLAN in-store AP will be sending tagged traffic from multiple VLANs to the in-store firewall and will, therefore, require a connection to a port configured as a trunk. The traffic that AvaLAN devices send for checking into our cloud services will be sent as untagged traffic so that you can manage this by configuring the native VLAN on the trunk port assigned to the dispensers. Trunk ports with a native VLAN available are sometimes called hybrid ports.
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