Question: Which interface and protocol are involved when an SRNC (Serving RNC) requests the transfer of a signaling message on the Signaling Radio Bearer 2 (SRB2) to a specific cell?
Option 1: Iub interface, using NBAP (Node B Application Part) signalling
Option 2: Iur-g interface, using RNSAP (Radio Network Subsystem Application Part) signalling for SRB2 transfer
Option 3: Iu-PS interface, using RANAP (Radio Access Network Application Part) signalling for CCCH messages
Option 4: Iur-g interface, using RNSAP (Radio Network Subsystem Application Part) signalling for Uu message on CCCH, initiated by the SBSS to the DRNC
Explanation: This question requires understanding of UTRAN interfaces and signaling protocols. The correct answer, Option 2, is specific to the Iur-g interface, which is used between RNCs (Radio Network Controllers) for certain operations, including the transfer of signaling messages like those on SRB2 as described in the context. RNSAP is the protocol used over this interface for such signaling. The other options are incorrect because they either refer to different interfaces (Iub, Iu-PS), different protocols (NBAP, RANAP), or a scenario (Option 4) that, while related, does not precisely match the question's specifics about SRNC, SRB2, and the cell context.