The below diagram depicts the interaction between two Cosmos SDK-based chains, Osmosis and Landslide, through the IBC protocol. The IBC Relayer acts as a mediator between the two chains.
When a message transfer is initiated by Chain A (Osmosis), it generates a packet commitment (hash) and stores it in the KV store by key (port, channel, sequence). Then it emits a packet event and the IBC Relayer handles this event. The IBC Relayer queries for the packet commitment proof from Chain A (Osmosis), which is then returned by Chain A (Osmosis). The IBC Relayer creates a message to relay the packet to Chain B (Landslide).
After receiving the message, Chain B (Landslide) sends back a WriteAck result to the IBC Relayer. The IBC Relayer then queries for the acknowledgement proof from Chain B (Landslide), which is then returned by Chain B (Landslide). The IBC Relayer creates an acknowledgement message containing the packet, acknowledgement, and proofs, which is then sent to Chain A (Osmosis).