diff --git a/src/runtime2/communication.rs b/src/runtime2/communication.rs
index e69de29bb2d1d6434b8b29ae775ad8c2e48c5391..f3397eeba71f6fff803b9329a782911f1e2652ee 100644
--- a/src/runtime2/communication.rs
+++ b/src/runtime2/communication.rs
@@ -0,0 +1,38 @@
+use super::runtime::*;
+
+#[derive(Copy, Clone)]
+pub struct PortId(pub u32);
+
+impl PortId {
+    pub fn new_invalid() -> Self {
+        return Self(u32::MAX);
+    }
+}
+
+pub struct Peer {
+    pub id: CompId,
+    pub(crate) handle: CompHandle,
+}
+
+pub enum PortKind {
+    Putter,
+    Getter,
+}
+
+pub enum PortState {
+    Open,
+    Closed,
+}
+
+pub struct Port {
+    pub self_id: PortId,
+    pub peer_id: PortId,
+    pub kind: PortKind,
+    pub state: PortState,
+    pub local_peer_index: u32,
+}
+
+/// Public inbox: accessible by all threads. Essentially a MPSC channel
+pub struct InboxPublic {
+
+}
\ No newline at end of file