Lantronix S3220 Series User Guide Rev J PDF 34.75 MB - Page 27

Transition Networks ION x222x / x32xx User Guide How VLAN Tunneling Works A tunnel port is a port that is configured to support 802.1q (VLAN) tunneling. Each customer comes in on a dedicated customer‐facing port on the service provider switch where a VLAN that is dedicated to tun‐ neling is assigned. The service provider assigns each customer an outer VLAN tag or a service provider VLAN tag that uniquely identifies him within the network. The service provider VLAN also keeps the cus‐ tomer traffic isolated from other customer traffic that is traversing the same service provider network. That service provider VLAN supports all the VLANs of the customer. VLAN Tunneling refers to multiple tagging of dot1Q frames as they enter a service provider switch from a client switch. VLAN Tunneling can tag or untag any frames that it receives from the customer tag. VLAN Tunneling also has native VLAN frames that are untagged. The service provider switch adds the outer VLAN tag. Tagged and untagged customer traffic comes from a port on a customer device and enters the service‐ provider edge switch through a tunnel port. Each customer edge port that is connected to a VLAN tunnel port is typically configured as a trunk port. The customer trunk port is unaware of the provider VLAN tunnel and can communicate with all of its other trunk ports that are connected to the metro network of the provider as if they were directly connected. This makes the process transparent to the enter‐ prise's switching network. A hub customer edge might have connectivity to two remote spoke sites and have only half of the VLANs from the hub site go to one site, and the remaining VLANs go to the second remote site. This is possible using two service provider VLANs for this enterprise customer when certain sites need to see only some and not all of the VLAN traffic from the hub site. 33472 Rev. J Figure 5: VLAN Tunneling Example https://www.transition.com Page 27 of 700