Without this information, a time distribution network is a black box. TimeKeeper looks at all the sources of time, in any protocol, that it can see around it, and tracks each source back to its source. These maps, especially in larger and older firms, find all sorts of interesting things. They find “redundant” time sources that are not. They find odd cycles that can cause dumb NTP implementations to oscillate between sources. They can find unexpectedly long legs (edge length corresponds to one way delay). In one corporate network they discovered a GPS source that was, to the surprise of users, failing over to a modem connected to a trans-Atlantic feed. These pictures are a way of creating actionable information from reams of difficult to understand data.