MPLS Configuration on Cisco IOS Software

VPLS Topology—Single PE or Direct Attachment

The single PE or direct attachment architecture uses a flat architecture and supports Ethernet port, 802.1Q VLAN, and dot1q tunnel modes. The CEs are directly connected to the PE routers, and this architecture involves the creation of a separate VSI for each customer. Customer traffic originating from the CE in native Ethernet or VLAN tagged frames are MPLS encapsulated with an AToM stack. Direct attachment VPLS also uses a full mesh of directed LDP and tunnel LSPs between all the PE routers. Although this creates signaling overhead, the real detriment to large-scale deployment is the packet replication requirements for each provisioned VC on a PE router. Due to scalability constraints, this solution ...