Performance Routing (PfR) uses Protocol Independent Routing Optimization (PIRO) to control path selection for Open Shortest Path First (OSPF) and Intermediate System-to-Intermediate System (IS-IS) routes. PfR can control path selection directly for Border Gateway Protocol (BGP), Enhanced Interior Gateway Routing Protocol (EIGRP), and static routes.
PfR enhances traditional routing methods by dynamically selecting the best path for traffic classes based on network performance. The path selection procedure can be influenced by several factors, including delay, packet loss, reachability, throughput, jitter, and mean opinion score (MOS). When PfR wants to modify a path for a traffic class, it will search for a parent route, which is an exact matching route or a less specific route. PfR will search for a parent route in the following locations, in order:
1. BGP routing database
2. EIGRP routing database
3. Static route database
PIRO extends the capabilities of PfR by searching for a parent route within the IP Routing Information Base (RIB) after the other locations have been searched.