updated protocol definition

1 files changed, 12 insertions, 7 deletions

diff --git a/doc/protocol.md b/doc/protocol.md
index 3c53a2a..74bdbd2 100644
--- a/doc/protocol.md
+++ b/doc/protocol.md
@@ -4,8 +4,9 @@ Messages
 init
 ----
 
-The streamer-id and tags are optional. All other fields are mandatory. If the streamer-id
-is not defined all data-update messages must contain a streamer-id.
+All fields except version are optional. The values in this message are treated as
+defaults which will be used if the corresponding value is missing in subsequent
+update messages.
 
 {
   "version": 1,
@@ -18,15 +19,19 @@ is not defined all data-update messages must contain a streamer-id.
 data-update
 -----------
 
-All elements inside data are optional. The update must contain all data gathered between
-start-time and start-time + duration-ms.
-If defined by the init message the streamer-id is optional as well and when present it's
-values override the values of the init message.
+All values which have been defined by the init message are optional. In any case the
+values from data updates override values from init. Stateless interfaces will not use
+init messages and therefore all values must be defined here.
+If an interface (i.e. REST) has other means to detect protocol versions the version
+field may be omitted entirely.
 
 {
+  "version": 1,
+  "hostname": "myhostname",
+  "streamer-id": { "content-id": "av-orig", "format": "flash", "quality": "medium" },
+  "tags": [ "elevate", "2014", "discourse" ]
   "start-time": "2014-08-03T12:34:56.123Z",
   "duration-ms": 5000,
-  "streamer-id": { "content-id": "av-orig", "format": "flash", "quality": "medium" },
   "data": {
     "clients": [
        { "ip": "127.0.0.1", "port": 1234, "bytes-sent": 12094, "user-agent": "Mozilla Version 28", .... },