Chapter Questions
Describe the media gateway (MG), the signaling gateway (SG), and the media gateway controller (MGC). Which protocols are executed between these nodes?
Show how short message service (SMS) can be implemented in GSMIP. Do you need to add new packages in the MGCP Connection Model? (See Chapter 1 for details of SMS.)
How can a QoS mechanism be implemented in GSM-IP? Which MGCP command is responsible for QoS setup?
Please implement a GSM-IP system using H.323. Can GSM-IP and/or vGPRS be implemented in SIP (see Chapter 12)?
Consider a vGPRS call session between an MS and an H. 323 terminal. Suppose that the H. 323 user hangs up the phone first. Draw the callrelease message flow.
In vGPRS, how do SGSN and GGSN support VoIP QoS? (Hint: See the QoS model described in Chapter 4.)
Draw the vGPRS location update message flow when the MS movement involves the crossing of two SGSNs.
Redraw the vGPRS inter-system handoff message flow in Figure 10.18 such that both VMSC1 and VMSC2 are connected to the same SGSN.
Draw the registration message flow due to MS movement in vGPRS. Point out the steps that are different from the standard GSM registration procedure.
Compare vGPRS with the 3GPP TR 21.978 approach in terms of MS call termination.
Show the message flow for call setup from a GSM-IP user to a vGPRS user through the Internet.