For questions about FRR (Fast ReRoute), where it is a MPLS (Multiprotocol Label Switching) and IP resiliency technology to provide fast traffic recovery upon link or router failures for mission critical services.

MPLS fast reroute (FRR) refers to local protection methods such as one-to-one and many-to-one (facility) backup. In the general networking community, the term FRR has become a shorthand way of describing the entire spectrum of MPLS traffic protection mechanisms.

http://www.juniper.net/techpubs/en_US/junos11.4/information-products/topic-collections/nog-mpls-frr/nog-mpls-frr.pdf