Bringing high availability to BGP: A survey

The Border Gateway Protocol (BGP) interconnects the Autonomous Systems forming the global Internet. The high stability and scalability offered by the protocol motivated its use for other critical networking services, making BGP a key component for IP networks. BGP was, however, unable to adapt to network changes fast enough to fulfill the Service Level Agreements imposed to operators. Different proposals had been made in the last years to adapt BGP to these stricter requirements. This document surveys these enhancements, focusing on those already accessible to network operators or in an advanced state of standardization. We describe and compare these techniques with different alternatives, and provide basic recommendations for their deployment and operation.