 The user's data flow bypasses the Radio Network Controller (RNC) and the SGSN of the previous 3GPP UMTS architecture versions, thus simplifying the architecture, reducing costs and delays.This is nearly identical to the 3GPP Long Term Evolution (LTE) flat architecture as defined in the 3GPP standard Rel-8.The changes allow cost effective modern link layer technologies such as xDSL or Ethernet, and these technologies are no longer tied to the more expensive and rigid requirements of the older standard of SONET/SDH and E1/T1 infrastructure.