Distributed Universal Number Discovery (DUNDi) is a VoIP routing protocol that provides directory services for Asterisk systems.
In the DUNDi configuration one can limit the number of consecutive lookups between peers by setting the TTL.
Low values represent a high priority and must be chosen first when more than one answer is received from a lookup.
The above DUNDi lookup tells the PBX to ask the known peers if they know how to reach extension 301 in the "priv" network.
The answer consists of 6 parts: In order to prevent the network from overloading and at the same time keep the responses as quick as possible, the involved peers will cache the lookups they see.