BRAS CGN Failover via DHCP Public IP Assignment
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Solution Overview
Problem
The existing methods for carrier grade network address translation (CGN) in broadband remote access servers (BRAS) require complex and costly procedures for failover, leading to prolonged service recovery times when a CGN fails, as they necessitate switching traffic to a backup BRAS and reconfiguring IP addresses.
Innovation Solution
Implementing a method where the BRAS directly assigns a public IP address to terminals upon detecting a CGN failure, either from a local or remote standby public address pool, eliminating the need for traffic transfer and backup CGN configuration, thereby shortening service recovery times and reducing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If backup BRAS with CGN is configured for failover, then system reliability is improved, but device complexity and cost increase
Solution Approach 1:
The patent extracts the CGN function from the BRAS hardware and implements it as a software feature on the DHCP server. This allows the BRAS to failover to a backup without requiring the backup to have identical CGN hardware configurations, thereby reducing device complexity while maintaining reliability
Solution Approach 2:
The DHCP server is given multiple functions: it serves as both the primary DHCP server and a backup CGN address pool provider. When the BRAS fails, the DHCP server can directly assign public IP addresses from its standby pool, eliminating the need for separate backup CGN infrastructure
2Reliability
If traffic switching to backup BRAS is performed upon CGN failure, then system reliability is improved, but service recovery time increases
Solution Approach 1:
The DHCP server pre-configures a standby public IP address pool in advance. When BRAS failure occurs, addresses are immediately available from this pre-prepared pool without requiring traffic switching or reconfiguration delays, thus reducing service recovery time while maintaining reliability
3Reliability
If backup CGN configuration is implemented, then system reliability is improved, but operational cost increases
Solution Approach 1:
The patent merges the backup CGN address pool functionality into the existing DHCP server infrastructure. This consolidation eliminates the need for separate backup CGN hardware and licensing costs, reducing operational expenses while maintaining system reliability through the same DHCP server that already provides address management services
Data Source
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AI summary
Embodiments of the present invention provide an address assignment method, a device, and a system. The method is applicable to a network having a broadband remote access server BRAS, where the BRAS is set with carrier grade net address translation CGN, the method including: detecting, by the BRAS, that the locally set CGN fails; receiving, by the BRAS, an access request sent by a terminal; and assigning, by the BRAS, a public IP address to the terminal. In the embodiments of the present invention, when the CGN fails, terminal traffic transfer is not required, thereby shortening terminal service recovery time when the CGN of the BRAS fails, and lowering costs.