A method of establishing a terminating communication session originated from another party towards a user equipment, UE, by way of a media gateway, MGW, controlled by a control server, the communication session comprising a secure connection between the UE and the MGW, and wherein the setup of the secure connection comprises a security handshake procedure, the method comprising: • prior to receiving a communication session set-up request at the control server: ∘ determining by the control server whether the MGW supports a procedure for early commencement of the security handshake; ∘ providing by the UE to the control server an indication that the UE supports the procedure for early commencement of the security handshake procedure and connection parameters for use in the security handshake; and ∘ storing the indication and connection parameters at the control server; • on receiving the terminating communication session set-up request originated from the another party by the control server, if the UE has provided an indication that it supports the procedure and connection parameters, and the control server has determined that the MGW supports the procedure: ∘ sending an instruction from the control server to the MGW to commence the security handshake procedure, the instruction comprising the connection parameters for the UE, wherein the instruction is sent before sending the communication session setup request towards the UE; ∘ commencing the handshake procedure to set up a secure communications session; and ∘ completing the establishing of the communication session. • prior to receiving a communication session set-up request at the control server: ∘ determining by the control server whether the MGW supports a procedure for early commencement of the security handshake; ∘ providing by the UE to the control server an indication that the UE supports the procedure for early commencement of the security handshake procedure and connection parameters for use in the security handshake; and ∘ storing the indication and connection parameters at the control server; ∘ determining by the control server whether the MGW supports a procedure for early commencement of the security handshake; ∘ providing by the UE to the control server an indication that the UE supports the procedure for early commencement of the security handshake procedure and connection parameters for use in the security handshake; and ∘ storing the indication and connection parameters at the control server; • on receiving the terminating communication session set-up request originated from the another party by the control server, if the UE has provided an indication that it supports the procedure and connection parameters, and the control server has determined that the MGW supports the procedure: ∘ sending an instruction from the control server to the MGW to commence the security handshake procedure, the instruction comprising the connection parameters for the UE, wherein the instruction is sent before sending the communication session setup request towards the UE; ∘ commencing the handshake procedure to set up a secure communications session; and ∘ completing the establishing of the communication session. ∘ sending an instruction from the control server to the MGW to commence the security handshake procedure, the instruction comprising the connection parameters for the UE, wherein the instruction is sent before sending the communication session setup request towards the UE; ∘ commencing the handshake procedure to set up a secure communications session; and ∘ completing the establishing of the communication session.