Application Scenarios for Static Mapping
Figure 1 shows the main application scenario of static mapping. In this scenario:
The CPE serves as a user access device to allocate private IPv4 addresses to users and perform level-1 NAT on service traffic.
The BRAS works at the access layer of the MAN. Generally having a built-in DHCP server module, the BRAS allocates addresses to CPEs to communicate with the CGN device.
As the traffic convergence point, the CGN receives the static mappings, generates a static mapping table, and maintains it, implementing carrier-grade NAT.
The AAA server maintains the static mappings on the CGN device, authenticates, authorizes, and charges users (CPEs), and records and maintains user charging and account information.
The network management server manages the CGN device and sends the user address static mappings to the CGN device and AAA server.
