This illustration includes four different networks of routers arranged in a diamond shape. At the bottom point of the diamond is network AS1, which includes four routers, labeled 1a, 1b, 1c, and 1d. At the right point of the diamond is network AS2, which includes three routers, labeled 2a, 2b, and 2c. At the left point of the diamond is network AS3, which includes three routers, labeled 3a, 3b, and 3c. At the top point of the diamond is AS4, which includes three routers, labeled 4a, 4b, and 4c. CDN Server A is connected to router 3b, and advertises the IP address 212.21.21.21. CDN Server B is connected to router 1d, and advertises the same IP address as Server A. A note associated with router 2b indicates: "Receive BGP advertisements from 212.21.21.21 from AS1 and rom AS4. Forward towards Server B since it is closer.