CDNlink Project
DNS-based Request Routing
Fig. 1. DNS-based Request Routing by CDNlink
Studies in the literature indicated that two different client request routing (RR) methods, which can be classified as client-side and server-side, are used in commercial CDNs [4]. In client-side RR, the clients are issued the IP address of the best server by a Domain Name Server (DNS). This method is frequently called DNS-based RR [5]. Server-side RR uses URL forwarding to redirect clients to the best server; however, it still uses DNS to resolve the IP address of the server. Thus, the simplicity and transparent nature of the DNS are exploited to redirect clients to the best server without any modifications to the server, clients, or Web applications. Therefore, commercial CDNs, e.g., Akamai, NetFlix, etc., use DNS-based RR in their system..
Details about CDNlink design of DNS-based RR as follows:
1. Client
2. Router
3. DNS Server