Update the protocol document with details of the transfer protocol

PROTOCOL.md

@@ -20,3 +20,36 @@ Protocol Specification for groundstation
 * stationd shall implement a notification type to allow clients (web ui, native
   etc) to be notified immediately of new data.
 
+## Transfer of data
+
+* Data is requested by sending a serialized hash, with the keys:
+
+```javascript
+{
+    "type": REQUEST,
+    "request": KEYWORD, // KEYWORDs include LISTALLOBJECTS FETCHOBJECT
+    "id": UUID          // UUID shall be a uuid to marry up with the response
+}
+```
+
+* Data shall be replied to with a similar hash,
+
+```javascript
+{
+    "type": RESPONSE,
+    "phrase": KEYWORD, // KEYWORDs include TRANSFER and TERMINATE. more than a
+                       // single response is valid for a request, TERMINATE
+                       // signifies that the storage allocated to the request
+                       // may be freed
+    "id": UUID,        // The UUID sent with the request. In the case
+    "payload": PAYLOAD // The payload associated with the request. request type specific.
+}
+```
+
+* When a connection is initialized, the recieving node will check if it already
+  has a connection to the given party and sever it in that case.
+* Should the connection not be severed, the connecting party shall immediately
+  issue a `LISTALLOBJECTS` request. This will essentially kick off the event
+  loop, at this point all requests can be responded to in kind as a result of
+  the ordinary event loop without outside interference.
+