5G APN
Introduction to APN
An access point name (APN) identifies an external public data network (PDN) that a user needs to access. Users connect to a PDN using the APN of the PDN, as shown in Figure 13-4. An IP multimedia subsystem (IMS) network is a voice communications network provided by carriers. An enterprise data gateway is the entry point to the enterprise headquarters. Users can access the IMS network through APN 1 and access the enterprise headquarters network through APN 2.
APN Backup
To improve link reliability, the 5G modem of routers supports APN backup. That is, multiple APN profiles can be bound to the same cellular interface or cellular channel interface, and each APN profile can have a different priority configured. The APN configured in a high-priority APN profile is the active APN, whereas the APN configured in a low-priority APN profile is the standby APN. A router first accesses a network through the active APN. If the network is faulty, the router accesses the network through the standby APN.
5G Multi-APN
To access different networks, the 5G modem of a router supports multiple APNs (currently two APNs). A cellular interface on a router contains multiple cellular channel interfaces. Each cellular channel interface is a logical service interface that has its own IP address, DCC dial-up configuration, and services (such as voice, data, and VPN). Each APN is bound to a cellular channel interface, and multiple APNs share one cellular interface. In Figure 13-5, the router accesses the Internet through APN 1 for data communication and accesses an IMS network for VoIP communication through APN 2. The two APNs share the uplink bandwidth on the 5G cellular interface. In this case, QoS is required to schedule APNs for different services. Voice services have high real-time requirements. Therefore, QoS needs to be configured on the cellular interface to ensure that voice services are first scheduled.
