Chapter 4. Reimagining BGP Configuration
This chapter shows how router configuration can be reduced by completely eliminating interface IP addresses and specifying the remote-as of each neighbor. Both of these improvements will make configuring a BGP router in the data center a snap, and automation a breeze.
In Chapter 3, we showed how you could eliminate IP address usage from the BGP configuration. However, the operator still needs to configure IP addresses on the interfaces for BGP peering. Because these interface addresses are never used for anything but BGP configuration and their information is never propagated via BGP, their configuration is a meaningless holdover from the service provider world in the data center. Another issue mentioned toward the end of Chapter 3 about automating the configuration is the need to know the remote-as of the peer.
After we eliminate these two requirements, we’re left with a configuration that is homogeneous and duplication-free across the nodes, with the only node-specific content being the node’s ASN and its router-id. In other words, the configuration is very automation friendly, and simple.
To achieve these goals, we’ll need to understand a topic almost as old as routing: unnumbered interfaces, and how we adapt this construct to BGP.
The Need for Interface IP Addresses and remote-as
Because BGP runs on TCP/IP, it needs an IP address to create a connection. How can we identify this remote node’s address while at the same time not allocating ...