An arrangement and method for radio network relocation of a mobile terminal (114) from a first base station controller (122) to a second base station controller (122′) by anchoring at least some SGSN functions with respect to the first base station controller; and relocating at least some RNC functions from the first base station controller to the second base station controller. RNC (124), SGSN (132) and GGSN (134) components may be integrated together, and the RNC (124) may be parented by an SGSN. Alternatively, RANAP SGSN functionality may be split between SGSN and RNC, RANAP and user plane signals may be relayed by the first base station controller to the second base station controller, and the first base station controller may act as an anchor.