The TON Project uses its own peer-to-peer network protocols.
TON Blockchain uses these protocols to propagate new blocks, send and collect transaction candidates and so on.
While the networking demands of single-blockchain projects, such as Bitcoin or Ethereum, can be met quite easily (one essentially needs to construct a peer-to-peer overlay network and then propagate all new blocks and transaction candidates via a gossip protocol), whereas multi-blockchain projects, such as TON, are much more demanding (e.g. one must be able to subscribe to updates of only some shardchains, not necessarily all of them).
TON Ecosystem services (e.g. TON Proxy, TON Sites, TON Storage) run on these protocols.
Once the more sophisticated network protocols needed to support TON Blockchain are in place, it turns out that they can easily be used for purposes not necessarily related to the immediate demands of the blockchain itself, thus providing more possibilities and flexibility for creating new services in the TON Ecosystem.