Update PROTOCOL.md

1 files changed, 46 insertions, 8 deletions

diff --git a/PROTOCOL.md b/PROTOCOL.md
index 886161c..b6d249e 100644
--- a/PROTOCOL.md
+++ b/PROTOCOL.md
@@ -36,14 +36,52 @@ All payload types are described in following files:
 * [Kaitai Struct](https://git.sr.ht/~rctt/solec/blob/main/solec.ksy)
 * [SVG graph](https://git.sr.ht/~rctt/solec/blob/main/solec.svg)
 
-### Payload types
+## Client-server connection initialization
 
-| Type | Name         |
-|------|--------------|
-| 0x01 | Handshake    |
-| 0x02 | Ping         |
-| 0x03 | Pong         |
-| 0x04 | Message      |
-| 0xFF | Test         |
+1. Initialize TCP connection
+2. Receive `handshake`
+3. Send `hadnshake`
+4. Send `auth`
+5. Receive `success` or `error`
 
+## Client-server messaging
 
+After successfull auth server will listen for payloads of `message` type.
+Sending different payload will result in error and connection will be closed
+by the server.
+
+Message consist of following fields:
+* Source - address of the user sending a message
+* Target - address of channel or user receiving a message
+* Timestamp - set by user sending a message, UTC timezone
+* Content - UTF-8 string
+
+## Addresses
+
+Source and target addresses are similair to e-mail addresses. There are two
+parts separated by `@` where second part is address of the server where
+specific user or channel is registered on.
+
+Target addresses is set to user that created specific message. Messaegs can be
+relayed between servers so it's necessary to keep that info as part of the
+message.
+
+Channel addresses always starts from `#` to distinct them from user addresses.
+Because of that user address cannot start from this character.
+
+Channels can be grouped in a hierarchy. Levels of channels hierarchy are
+separated by `.`.
+
+`*` is special address reserved for broadcast messages send by the server
+administrator.
+
+| Type      | Address              |
+|-----------|----------------------|
+| user      | user@example.org     |
+| channel   | #channel@example.org |
+| broadcast | *@example.org        |
+
+## Channels hierarchy
+
+Channels can be groupped into a hierarchy. Channels hierarchy can be used to
+simplify moderation and management.
\ No newline at end of file