There are many ways to implement a p2p network structured, unstructured or hybrid. In structured architecture there are logfiles or nada(nano data centers) or supernodes generally and all these in order to know where to find the information. In DHT plan there is a key and a value pair hushed together. Hashing info must have the information e.x. query, response, error. Query belongs ping, find node, get peers, announce peer. The ID may contain information as 12304 that means the 123 piece of 4th block.