Hi, all, In order to scale the DNS root service, BGP anycast is widely used and then multiple mirror sites of a root server can be “copied” to different locations and different networks. However, from this aspect, the deployment of DNS root service is not so independent and its scalability will be affected by the BGP. For example, even a mirror site is deployed, the nearby resolution may reach other faraway node due to the decision of BGP (although yes, the geolocation is different from the network topology). Maybe the “local” mirror site can be deployed to attract more resolution traffic in the local network and the performance of overall DNS root service can still be improved (no matter of the deployed locations) from the global perspective, some metrics and measurements are still needed to optimize the deployment locations of the mirror sites. In this way, the performance of DNS root service and the global ability to defend the DDoS to DNS root service can be improved. This is a complex problem because the BGP is dynamic and the networking performance is also dynamic, but I think it is an interesting topic and valuable for the planning of new mirror sites deployments. BR, Zhiwei YAN Zhiwei