diff --git a/src/runtime2/communication.rs b/src/runtime2/communication.rs
index c615f06d5d5d08a99f8dbae16ff36c34639be553..c092fc99311d9c12835221b9707fe1e20b6827be 100644
--- a/src/runtime2/communication.rs
+++ b/src/runtime2/communication.rs
@@ -17,6 +17,11 @@ impl PortId {
     }
 }
 
+pub struct CompPortIds {
+    pub comp: CompId,
+    pub port: PortId,
+}
+
 #[derive(Debug, PartialEq, Eq, Clone, Copy)]
 pub enum PortKind {
     Putter,
@@ -56,9 +61,29 @@ pub struct DataMessage {
     pub content: ValueGroup,
 }
 
+#[derive(Debug)]
+pub enum PortAnnotationKind {
+    Getter(PortAnnotationGetter),
+    Putter(PortAnnotationPutter),
+}
+
+#[derive(Debug)]
+pub struct PortAnnotationGetter {
+    pub self_comp_id: CompId,
+    pub self_port_id: PortId,
+    pub peer_comp_id: CompId,
+    pub peer_port_id: PortId,
+}
+
+#[derive(Debug)]
+pub struct PortAnnotationPutter {
+    pub self_comp_id: CompId,
+    pub self_port_id: PortId,
+}
+
 #[derive(Debug)]
 pub struct MessageDataHeader {
-    pub expected_mapping: Vec<(PortId, Option<u32>)>,
+    pub expected_mapping: Vec<(PortAnnotationKind, Option<u32>)>,
     pub new_mapping: u32,
     pub source_port: PortId,
     pub target_port: PortId,