BGP PIC – Prefix Independent Convergence Fundemantals
BGP PIC ( Prefix Independent Convergence ) is a BGP Fast reroute mechanism which can provides sub second convergence even for the 500K internet prefixes by taking help of IGP convergence.
BGP PIC uses hierarchical data plane in contrast to flat FIB (Forwarding table) design which is used by Cisco CEF and many legacy platforms.
In a hierarchical dataplane , the FIB used by the packet processing engine reflects recursions between the routes.
I will explain the recursion concept throughout the post so don’t worry about the above sentence, it will make sense.
There are two implementation of BGP PIC concept and they can protect the network traffic from multiple failures.
Link, node in the core or edge of the network can be recovered under a second and most of the case under 100ms ( It mostly depends on IGP convergence, so IGP should be tuned or IGP FRR can be used ).
In this article I will not explained IGP fast convergence or IGP Fast reroute but you can read my Fast reroute mechanism article from here.
BGP PIC can be thought as BGP Fast Reroute Mechanism which relies on IGP convergence for the failure detection. ( All overlay Continue reading
