Think of DUNDi as a large phone book that allows you to ask peers if they know of an alternative VoIP route to an extension number or PSTN telephone number. For example, assume that you are connected to the DUNDi-test network (a free and open network that terminates calls to traditional PSTN numbers). You ask your friend Bob if he knows how to reach 1-212-555-1212, a number for which you have no direct access. Bob replies, “I don’t know how to reach that number, but let me ask my peer Sally.” Bob asks Sally if she knows how to reach the requested number, and she responds with, “You can reach that number at IAX2/dundi:very_long_password@hostname/extension.” Bob then stores the address in his database and passes on to you the information about how to reach 1-800-555-1212 via VoIP, allowing you an alternative method of reaching the same destination through a different network. Because Bob has stored the information he found, he’ll be able to provide it to any peers who later request the same number from him, so the lookup won’t have to go any further. This helps reduce the load on the network and increases response times for numbers that are looked up often. (However, it should be noted that DUNDi creates |
a rotating key and, thus, stored information is valid for a limited period of time