Simplified Network

Diameter routing function includes routing based on application ID and realm name, incoming peer ID, host name, command code subscriber ID (IMSI, MSISDN, PUI, PVI),etc.

Interworking of Diameter signaling networks constructed by different carriers facilitates service cooperation but also incurs network attacks through illegal signaling. The carriers need to screen illegal requests in Diameter signaling to make the Diameter signaling network more secure and reliable. Diameter signaling screening screens illegal request messages in Diameter signaling to enhance security and reliability of the Diameter signaling network.

SS7 routing function includes: routing on MTP3/M3UA layer, routing on SCCP layer, routing on MAP layer.

Similar to Diameter Signaling Screening, SS7 signaling screening screens illegal request messages in SS7 signaling to enhance security and reliability of the SS7 signaling network. SS7 Signaling Screening includes: screening on MTP3/M3UA layer, screening on SCCP layer, screening on MAP layer.

Mobile Number Portability is a service that enables subscribers to retain their existing numbers when they switch from one operator to another. MNP NE provides the query of subscriber home operator and HLR according to its subscriber number.

In the development of network, the stage of different network is always different. e.g. the network of operator A is 3G, the network of operator B is 4G. When different networks need to interwork, interworking equipment is needed to translate the different signaling between different networks.

By deploying an SCP, signaling links can be converged between NFs, simplifying the network architecture and reducing the number of links between NFs.

• Indirect communication: message forwarding and routing to destination NF/NF service; 
• Mode C: The NF performs service discovery, and the SCP forwards the signaling routes; 
• Mode D: The NF no longer discovers services. The SCP is responsible for the agent service discovery and signaling route forwarding.

BSF (Binding Support Function) implements the PDU session binding function for 5G users. In BSF, each PDU session stores the session binding information including user ID, DNN, UE address (IP address or MAC address), and PCF address selected by SMF. It provides the PCF address query service for AF or NEF to ensure that the AF can identify the UE's service based on the UE address, so that the N5/Rx interface messages can be routed to the corresponding PCF for the PDU session of the UE.

SEPP provides the following functions for 5G signaling protection: 

• As a non-transparent agent, SEPP forwards signaling between VPLMN and HPLMN (N32 interface); 
• Between SEPPs, mutual authentication and key negotiation, and secure transmission of signaling messages;
• Filtering signaling messages, screening illegal signaling messages, and checking anti-fraud at the application layer and IP layer;
• Topology hiding to restrict the internal topology to be visible to the outside.

• Providing functions such as NF registration, NF update and NF subscription/notification, to achieve automation NF management in the 5GC SBA; 
• Providing NF and service dynamic discovery services for local NFs and roaming NFs; 
• Providing an oAuth2-based authorization mechanism to prevent illegal NF access to the network and ensure network security of the communication between NFs.

• Providing information such as allowed NSSAI, configured NSSAI and target AMF set to the initial AMF to assist AMF to implement re-allocation; 
• Providing the NRF ID and NSI ID to AMF, to assist AMF to select SMF in local/roaming scenarios; 
• Providing TA-based NSSAI availability management and supporting subscription, unsubscription, update, notification and deletion for NSSAI-related availability information.

Providing the mobile network Gn/Gp DNS function and supporting multiple query methods such as recursive query and iterative query.