Versatile Routing and Services with BGP: Understanding and Implementing BGP in SR-OS

Foreword

Over the past decade we have witnessed an exciting evolution of Internet Protocol (IP) networks from best-effort networks providing basic Internet access services to true multi-service networks providing fixed residential and mobile broadband services, business Virtual Private Network (VPN) services, cloud services, and carrying more and more mission-critical applications.

IP networks have gradually replaced most of the legacy networks of the past, resulting in more efficient and converged network infrastructures. This is not only the case for service provider and enterprise networks; the same evolution applies to strategic industry networks such as defense, energy, health care, transportation, and government networks.

When it comes to IP networking, there is arguably no protocol more important or successful than the Border Gateway Protocol (BGP)—it is the protocol that has tied the Internet together over the course of its impressive development in the past 20-plus years.

As the scope of IP networking has evolved over time, so has BGP. BGP has been extended to enable new services such as IP VPN (BGP/MPLS IPv4 VPN and 6VPE) and Layer 2 VPN (Virtual Private LAN, Virtual Leased Line, and BGP/MPLS based Ethernet VPN) services, to support network optimizations such as those provided by large-scale MPLS network designs—now commonly known as seamless MPLS—to simplify operations, to enhance network security and to improve network stability, resiliency and reconvergence performance. ...