In this chapter, we provided an operational overview of security considerations for each MPLS VPN component?for example, P, PE and CE. Using a building block approach in order to understand essential service and topological factors that affect security mechanisms, we have recommended best practice guidelines for each MPLS VPN service component. We introduced topics and basic configurations, such as Layer 2, which we will further discuss in Chapters 7 and 9. Finally, we summarized the best practices into an implementation checklist and supplied actual configuration examples that highlight principles discussed in this chapter.