diff --git a/TransportApp.markdown b/TransportApp.markdown
index ebf898a..779580d 100644
--- a/TransportApp.markdown
+++ b/TransportApp.markdown
@@ -1,5 +1,9 @@
 TransportApp is an application that uses [BSP](BSP) to synchronise transport properties, which describe how to connect to devices over various transports.
 
+### Channel identifiers
+
+TransportApp uses a single channel with a random identifer.
+
 ### Message types
 
 **0: PROPERTIES** - The content is a [BDF](BDF) list with three elements: transport identifier (string), version (int), and transport properties (dictionary). The identifier and properties are supplied by the transport plugin. The version is incremented whenever the properties change.