RRC and RAB

Hello,

Sending requests and receipts is part of signaling, or the RRC. The shipment of purchases is the data part, or the RAB. In our scenario, the RRC are the Rails, and RAB is the full service of sending data between the UE and the CN.

• RRC: Radio Resource Control

• RAB: Radio Access Bearer

Note: the RRC is in Layer 3 - control plane, while the RAB occurs between the UE and CN, in the user plane.

Thanks

RRC stands for Radio Resource Control.  UE needs resources from UTRAN network, it requests for the same. UE needs resources when it wants to establish either CS call or PS call. In order to do this following three steps 

• RRC Connection Request: From UE to RNC
• RRC Connection Setup: RNC assigns traffic channel(i.e. transport channel) and creates SRB(Signaling Radio Bearer).
• RRC Connection Complete

RAB stands for Radio Access Bearer. AS entity provides NAS to take care of information transfer between UE and Core Network(CN). This is known as RAB.

RAB across the UMTS system end to end from UE(i.e. mobile) to MSC/SGSN. Based on functionality and position in the system, RAB are of two main types. RB and lu bearer. RB(Radio Bearer) is between UE and RNC entities while lu bearer is between RNC and Core Network(CN).

RB is used for both user data as well as signaling. The RB used only for signaling purposes is known as SRB(Signaling Radio Bearer) used in control plane. There is another term 'TRB' used to refer Traffic Radio Bearer. TRB is used in User Plane.

Based on circuit switched call (CS call) or packet switched call (PS call), RAB type lu-interface carry either voice or data information.