diff --git a/src/runtime2/communication.rs b/src/runtime2/communication.rs
index f3397eeba71f6fff803b9329a782911f1e2652ee..4fee962a9b41daa870d84b2b60e71585d5b630a3 100644
--- a/src/runtime2/communication.rs
+++ b/src/runtime2/communication.rs
@@ -1,3 +1,4 @@
+use crate::protocol::eval::*;
 use super::runtime::*;
 
 #[derive(Copy, Clone)]
@@ -11,6 +12,7 @@ impl PortId {
 
 pub struct Peer {
     pub id: CompId,
+    pub num_associated_ports: u32,
     pub(crate) handle: CompHandle,
 }
 
@@ -21,6 +23,7 @@ pub enum PortKind {
 
 pub enum PortState {
     Open,
+    Blocked,
     Closed,
 }
 
@@ -29,10 +32,36 @@ pub struct Port {
     pub peer_id: PortId,
     pub kind: PortKind,
     pub state: PortState,
-    pub local_peer_index: u32,
+    pub peer_comp_id: CompId,
+}
+
+pub struct Channel {
+    pub putter_id: PortId,
+    pub getter_id: PortId,
+}
+
+pub struct DataMessage {
+    pub source_port_id: PortId,
+    pub target_port_id: PortId,
+    pub content: ValueGroup,
+}
+
+pub struct ControlMessage {
+    pub id: u32,
+    pub sender_comp_id: CompId,
+    pub content: ControlContent,
+}
+
+pub enum ControlContent {
+    Ack,
+    Ping,
+    PortPeerChangedBlock,
+    PortPeerChangedUnblock,
+}
+
+pub enum Message {
+    Data(DataMessage),
+    Control(ControlMessage),
 }
 
-/// Public inbox: accessible by all threads. Essentially a MPSC channel
-pub struct InboxPublic {
 
-}
\ No newline at end of file