See [need link here] for algorithm details.

The NDN pub-sub algorithm is designed using the following criteria:

• subscriber-driven
• lightweight
• avoid unnecessary IO

It makes the following guarantees:

• each publisher will order its own messages by the order in which they were published; however, the mechanism for this ordering (i.e. a monotonically-increasing ID) will not maintain the guarantee across multiple publishers (in this case, an application-level mechanism, like a time-synchronized timestamp, must be used; alternatively, try ChronoSync)
• publishers will provide the messages published on a topic for a specified lifetime; even after being closed, the publisher must maintain a registered prefix and respond to subscriber requests for data
• subscribers will eventually discover all routable publishers