C800-universalk9-mz.spa.159-3.m10.bin

In 15.9(3)M10, BFD is available for physical interfaces but not consistently for IPv6 over generic tunneling. Adding BFD for Tunnel interfaces with IPv6 neighbor discovery proxy would allow <50ms failover instead of 20+ seconds via routing protocol hellos.

: Translates to Cisco IOS Release 15.9(3)M10 , where 15.9 is the major release line, (3) is the train identifier, and M10 represents the tenth maintenance rebuild of that release. c800-universalk9-mz.spa.159-3.m10.bin