improved documentation

docs/protocol/layers/framing.md

 # Framing Layer
 
+This describes the lowest layer of the protocol, on which the
+[Message Layer](message.md) rests.
+
+This layer is named the "framing" layer, because its only purpose is to frame
+messages of higher layers and negotiate basic features for this use case.
+
 ## State Machine
 
 The framing layer has two possible states: `HANDSHAKE` and `CONNECTED`.

docs/protocol/layers/message.md

 # Message Layer
 
+This describes the second layer of the protocol, the message layer, which rests
+upon the [Framing Layer](framing.md).
+
 ## State Machine
 
-The framing layer has two possible states: `HANDSHAKE` and `CONNECTED`.
+The message layer has two possible states: `HANDSHAKE` and `CONNECTED`.
 It starts off in `HANDSHAKE` state.
 
 ## Handshake State

docs/protocol/layers/overview.md

-# Layers
-
-The lowest layer is the [Framing Layer](framing.md), on top of that rests the
-[Message Layer](message.md).
-
-How to interpret those messages is going to be described at a later time.
\ No newline at end of file

mkdocs.yml

@@ -13,7 +13,6 @@ nav:
     - "Upgrade Guide": usage/upgrade_guide.md
   - "Protocol":
     - "Layers":
-      - "Overview": protocol/layers/overview.md
       - "Framing": protocol/layers/framing.md
       - "Message": protocol/layers/message.md
     - "Serialization":