Signaling radio bearers
Signaling Radio Bearers (SRBs) are defined as Radio Bearers (RBs) that are used only for the transmission of RRC and NAS messages. More specifically, the following SRBs are defined: SRB0 is for RRC messages using the CCCH logical channel. SRB1 is for RRC messages (which may include a piggybacked NAS message) as well as for…