We are using protobuf RPC messages between peers. Here's what the protobuf messages looks like, as defined in the PubSub interface. Please see [PubSub interface spec](https://github.com/libp2p/specs/blob/master/pubsub/README.md) for more details.
In this section we specify two things how WakuSub is using these messages.
## Protobuf
```protobuf
message RPC {
repeated SubOpts subscriptions = 1;
repeated Message publish = 2;
message SubOpts {
optional bool subscribe = 1;
optional string topicid = 2;
}
message Message {
optional string from = 1;
optional bytes data = 2;
optional bytes seqno = 3;
repeated string topicIDs = 4;
optional bytes signature = 5;
optional bytes key = 6;
}
```
WakuSub does not currently use the `ControlMessage` defined in GossipSub.
However, later versions will add likely add this capability.
`TopicDescriptor` as defined in the PubSub interface spec is not currently used.
## RPC
These are messages sent to directly connected peers. They SHOULD NOT be
gossiped. See section below on how the fields work.
## Message
The `from` field MAY indicate which peer is publishing the message.
