docs.waku.org/docs/overview/concepts/protocols.md

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Protocols

Waku takes a modular approach, providing a range of protocols that enable applications to control the trade-offs involved in the Anonymity Trilemma. This flexibility empowers applications to make informed choices regarding the desired balance between anonymity, scalability, and latency. Here are the main protocols provided by Waku:

Relay

Relay protocol employs a Pub/Sub architecture to facilitate message routing among peers. It extends the libp2p GossipSub protocol to create a privacy-focused peer-to-peer messaging protocol that enables secure communication channels, encryption, and protection against censorship. It also scales the Waku Network to accommodate many nodes efficiently.

RLN Relay

RLN Relay protocol extends the Relay protocol by using Rate Limit Nullifiers (RLN) to provide efficient and economic spam prevention. It enforces a rate limit on messages over time for all peers in the network, economically preventing spam, and imposes financial penalties and network removal for spammers. You can find more details in the RLN Relay blog post.

Filter

Filter protocol allows light nodes to selectively subscribe to specific messages transmitted by other peers using content topics. It is designed to be a lightweight alternative for accessing the Relay network, particularly tailored for devices with limited bandwidth.

:::info Filter protocol helps optimize bandwidth usage, but it has fewer privacy guarantees as it must disclose the content topic to its peers to retrieve messages. :::

Store

Store protocol is responsible for storing messages relayed in the network, making it possible to query and retrieve them later. This functionality benefits offline peers by enabling them to retrieve missed messages upon reconnection.

:::info Using Relay and Filter protocols is recommended when a node is online, as Store does not guarantee data availability. The Store protocol is suitable for retrieving messages when connecting to the network, like when a dApp starts. :::

Light Push

Light Push is a Request/Response protocol for nodes with limited bandwidth and short connection windows. It allows a client to receive an acknowledgment when sending messages, indicating that at least one peer has received them. Subsequently, the remote peer forwards these messages to the Relay network.

:::info While the Light Push protocol acknowledges the receipt by the remote peer, it does not guarantee network-wide propagation. :::

Waku Message

Waku Message specifies the message structure used in the Waku Network. It defines the attributes and metadata fields that accompany a message, including the following:

• content_topic attribute for content-based filtering.
• payload attribute containing the message data payload to be sent.
• meta attribute for conveying additional details to various protocols for application-specific processing.
• timestamp attribute signifying the time at which the message was generated by its sender.
• ephemeral attribute specifying whether the network should not persist the message.