Dell SmartFabric OS10 User Guide Release 10.5.4

VLAN stacking

VLAN stacking enables service providers to offer separate VLANs to customers with no coordination between customers, with minimal coordination between customers and the provider.

Using only 802.1Q VLAN tagging, all customers must use unique VLAN IDs to ensure that traffic is segregated, and customers and the service provider must coordinate to ensure that traffic is mapped correctly across the provider network. Even under ideal conditions, customers and the provider may share the 4094 available VLANs.

Instead, VLAN stacking allows service providers to add their own VLAN tag to frames traversing the provider network. The provider can differentiate customers even if they use the same VLAN ID, and providers can map multiple customers to a single VLAN to overcome the 4094 VLAN limitation. The providers network forwarding decisions are based on the provider VLAN tag only. This tag enables the provider to map traffic through the core independently of the customer; the customer and provider only coordinate at the provider edge.