RA Option Bit,Description,Reference
0,M - Managed Address Configuration Flag,[RFC4861]
1,O - Other Configuration Flag,[RFC4861]
2,H - Mobile IPv6 Home Agent Flag,[RFC3775]
3,Prf - Router Selection Preferences,[RFC4191]
4,Prf - Router Selection Preferences,[RFC4191]
5,P - Neighbor Discovery Proxy Flag,[RFC4389]
6,S - SNAC Router Flag,[RFC-ietf-6man-snac-router-ra-flag-03]
7-53,R - Reserved; Available for assignment,[RFC5175]
54-55,Private Experimentation,[RFC5175]