Routing is the way to determine where to find a given content, peer, or IPNS record.

Delegated Routing V1 HTTP API
Delegated routing is a mechanism for IPFS implementations to use for offloading content routing, peer routing and naming to another process/server. This specification describes an HTTP API for delegated routing of content, peers, and IPNS.
Bitswap Protocol
Bitswap is a libp2p data exchange protocol for finding, sending and receiving content addressed blocks of data. It attempts to acquire blocks from the p2p network that have been requested by the client, and also send blocks to others who want them.