Content

| 10.1 |  | Ethernet Solutions for Transparent LAN Services |
| 10.1.2 |  | VLAN tunneling |

VLAN tunneling in the metro environment allows customers to extend their logical network topology across wide geographic areas. This comes into play especially when VoIP technologies are implemented. Without VLAN tunneling, customers are forced to renumber their existing VLANs, or the service provider is forced to provide some sort of VLAN translation at the access point to support multiple customers with overlapping VLAN numbers.

However, through DWDM and separate wavelength routing solutions, each customer is completely segmented from the others, allowing complete autonomy.

In Figure , VLAN service for customers A and B is illustrated. VLAN tunneling allows the service provider to support overlapping VLAN numbers on the same physical port.

Customer | VLAN
A | 1, 2, 3, 4, 5
B | 1, 2, 3

VLAN tunneling supports the isolation of customer A's VLAN 1, 2, and 3 from customer B's VLAN 1, 2, and 3 over the same physical optical interface. Therefore, support is provided for VLAN 1, 2, 3, 4, and 5 for customer A and VLAN 1, 2, and 3 for customer B over the same fiber.