UTRAN means Universal Terrestrial Radio Access Network which is used as a umbrella term for the the access network in UMTS which consist of Air Interface, NodeB and RNC. Single UTRAN serves both CS (Circuit Switched) and PS (Packet Switched) network connected with the IuCS and IuPS interface to the core network.
The eUTRAN means Evolved Universal Terrestrial Radio Access Network and is used as a umbrella term for the access network for the LTE technology it consists of Air Interface and eNodeB (both RNC and Node B functions are done by eNodeB in LTE). eUTRAN is a flat IP architecture as opposed to UMTS-UTRAN.
