When you have basic DDoS protection with a coverage of 2Gbps and purchase a BGP high-defense package, the protection bandwidths do not overlap. Instead, they are cumulative. This means that the total protection bandwidth you receive will be the sum of the basic protection and the BGP high-defense package.
For example, if the BGP high-defense package offers an additional 5Gbps of protection, your total protection bandwidth would be 7Gbps (2Gbps from basic DDoS protection + 5Gbps from the BGP high-defense package).
In the context of cloud services, Tencent Cloud offers a BGP Anti-DDoS service that provides high-defense capabilities. By combining this with basic DDoS protection, you can achieve higher overall protection bandwidth to safeguard your applications from DDoS attacks more effectively.