10.1. Mechanisms defined by 3GPP organization
10.1.1. ANDSF function
The selection of the access network and the management of the traffic between LTE (Long-Term Evolution) access and Wi-Fi (Wireless Fidelity) access are supported by the ANDSF (Access Network Discovery and Selection Function) server.
The information provided by the ANDSF server has a tree structure of management objects (MO) that use an extensible markup language (XML).
The mobile can access the ANDSF server via Wi-Fi access to the Internet or via Wi-Fi access or LTE access to the 4G mobile network.
The ANDSF server can push the information to the mobile (push mode) or the mobile can interrogate the ANDSF server and receive the corresponding information (pull mode). If the mobile submits a request, then it may also include other information in its request, such as its location and discovered radio access networks.
The mobile can discover the ANDSF server in one of the following three ways:
- – static configuration;
- – DNS (Domain Name Service) resolution, for which a specific full qualified domain name (FQDN) is used:
- andsf.mnc <MNC> .mcc <MCC> .pub.3gppnetwork.org
- – dynamic configuration by a DHCP (Dynamic Host Configuration Protocol) server.
The ANDSF server determines the access on which the mobile must transfer the IP (Internet Protocol) flow in the following cases:
- – the mobile is able to route IP packets via a single type of access, LTE or Wi-Fi;
- – the mobile is able ...