mentations. In the early 2000s, the Internet and private data services were merged onto a common MPLS infra- structure. In the mid-2000s, Ethernet started to become the transport technology for both access and core trunking, supplanting the synchronous optical networking (SONET) technologies. On this common IP MPLS technology built on Ethernet links, various services were imple- mented in the network edge where access and core met. These edges were the PE routers or service gateways that created public and private layer 2 and layer 3 services. A nonexhaustive list of edge network services on these service provider networks as are follows: Internet broadband service: Implemented on Broadband Network Gateways (BNGs, also called Broadband Remote Access Server). This provides the ubiquitous broadband con- sumer and small business Internet service. The BNG implements per subscriber IP address allocation and routing, security filters, class of service policy enforcement, and usage sta- tistics. In the service provider space, these have been accessed by various types of DSL technologies and more recently passive optical network (PON) technologies. Enterprise dedicated Internet service: For large enterprises, PE routers provide similar functions to the BNG. They provide per customer IP address allocation and routing, secu- rity filters, denial of service (DOS) protection, and access connectivity monitoring. Internet peering: Implemented on large-edge IP routers that exchange Internet routes with other Internet transit providers. Internet peering is what creates the global Internet reach- ability across all the ISPs. These peering routers implement various security filters and route policies that protect the ISP infrastructure and the Internet at large. Service-provider-based IP VPN service: Implemented on IP VPN PE routers. This service provides private IP networks for interconnecting sites using IP routing. This is used both by enterprises to create private IP intranets and internally for service provider infrastruc- tu