This chapter describes design alternatives for removing interdependence of data centers by using spanning-tree isolation techniques.
Data center Layer 2 interconnect solutions that use the Virtual Private LAN Service (VPLS) offer the following key advantages:
• Multisite Layer 2 transport over Layer 3 protected links
• Spanning-tree isolation in the core network that connects remote locations
Several designs exist for data center Layer 2 connectivity because a VPLS device can connect to the aggregation switch in various ways. These designs depend on the following conditions:
• IEEE 802.1Q-in-Q VLAN tag (QinQ) for VLAN scalability
• Monotenant or multitenant data center with local ...