RRC RAB RLC

Radio Access Bearer (RAB) is used for the transfer of user data. One or more independent and

simultaneous UE-CN Radio Access Bearer connections can exist for each user.

Signalling connection is divided into two parts: RRC connection and Iu connection. This implies

that the UE may have separate signalling connections, one to each CN domain (packet and circuit

switched).

Radio Bearer (RB) is the service offered by the Access Stratum between RNC and UE on top of layer

2.

Radio Link (RL; not shown in the slide) is a bi-directional connection between an UE and a base

station cell. Each RL is comprised of all the channels that are associated with the same physical layer

control channel (DPCCH).