A DOoM 2 object address consists of a hierarchical sequence of node names. In the initial release, a node name must consist of at most 31 case-sensitive alphanumeric (A-Z, a-z, 0-9, _) octets. Subsequent releases may extend this using an escape mechanism to non-English character sets. Node names are separated by colons in a string representation of an address, with the most significant node appearing first.
An example of a valid address might be "nsa:john_chew:board_front_end".
Each router is responsible for a (sub)hierarchy of the address space, which forms a graph-theoretical forest rooted at the backbone routers.