Internet Access and VoIP Communication Using 3G Multi-APN

For some enterprise branches that access the Internet using 3G, they also need to connect to the IP Multimedia Subsystem (IMS) network for Voice over Internet Protocol (VoIP) communication. 3G multi-Access Point Name (APN) can meet the requirement.

Figure 11-6 shows the 3G multi-APN scenario of an enterprise branch.

1. The router that supports 3G access, for example, the Router in Figure 11-6, is deployed in the enterprise branch.
2. The 3G interface is virtualized into two channel interfaces, and each channel interface is similar to a logical interface. The channel interface can have an independent IP address, can be used for Dial Control Center (DCC) dial-up, and can be configured with services such as voice and VPN.
3. Two APNs can be created on the Router. One APN is used to identify the Internet, and the other APN is used to identify the IMS network.
4. Each of the 3G channel interfaces is bound to an APN. One channel interface is used for Internet access, and the other channel interface is used to connect to the IMS network for VoIP communication. IPSec is configured on the channel interface that is connected to the Internet and IPSec VPN is created between the headquarters and branch. IPSec ensures secure data exchanges between the headquarters and branch.
5. The two channel interfaces share the uplink bandwidth of the 3G interface, so QoS needs to be deployed to ensure that key services can be scheduled first. For example, to improve the quality of VoIP services, when the two channel interfaces transmit VoIP and data services respectively, you can configure QoS on the 3G interface to ensure that VoIP services are scheduled first.

Figure 11-6 Enterprise branch using 3G multi-APN for Internet access and VoIP communication