diff --git a/src/runtime2/connector.rs b/src/runtime2/connector.rs
index 518df447c90e662382a0aaa57b9afc856d5eada9..3f75f4875bc9236146b9d7e95b5b23d8769bf670 100644
--- a/src/runtime2/connector.rs
+++ b/src/runtime2/connector.rs
@@ -3,24 +3,8 @@ use std::collections::HashMap;
 use crate::{PortId, ProtocolDescription};
 use crate::protocol::{ComponentState, RunContext, RunResult};
 use crate::protocol::eval::{Prompt, Value, ValueGroup};
-use crate::runtime2::inbox::{Inbox, Message};
-
-#[derive(Clone, Copy, PartialEq, Eq)]
-pub(crate) struct PortIdLocal {
-    pub id: u32,
-}
-
-impl PortIdLocal {
-    pub fn new(id: u32) -> Self {
-        Self{ id }
-    }
-
-    // TODO: Unsure about this, maybe remove, then also remove all struct
-    //  instances where I call this
-    pub fn new_invalid() -> Self {
-        Self{ id: u32::MAX }
-    }
-}
+use crate::runtime2::inbox::{Inbox, OutboxMessage};
+use crate::runtime2::port::PortIdLocal;
 
 /// Represents the identifier of a branch (the index within its container). An
 /// ID of `0` generally means "no branch" (e.g. no parent, or a port did not
@@ -67,7 +51,7 @@ pub(crate) struct Branch {
     sync_state: SpeculativeState,
     next_branch_in_queue: Option<u32>,
     // Message/port state
-    inbox: HashMap<PortIdLocal, Message>, // TODO: @temporary, remove together with fires()
+    inbox: HashMap<PortIdLocal, OutboxMessage>, // TODO: @temporary, remove together with fires()
     ports_delta: Vec<PortOwnershipDelta>,
 }
 
@@ -261,6 +245,23 @@ impl BranchQueue {
     }
 }
 
+/// Public fields of the connector that can be freely shared between multiple
+/// threads. Note that this is not enforced by the compiler. The global store
+/// allows retrieving the entire `Connector` as a mutable reference by one
+/// thread, and this `ConnectorPublic` by any number of threads.
+pub(crate) struct ConnectorPublic {
+    pub inbox: Inbox,
+}
+
+impl ConnectorPublic {
+    pub fn new() -> Self {
+        ConnectorPublic{
+            inbox: Inbox::new(),
+        }
+    }
+}
+
+// TODO: Maybe prevent false sharing by aligning `public` to next cache line.
 pub(crate) struct Connector {
     // State and properties of connector itself
     id: u32,
@@ -271,8 +272,8 @@ pub(crate) struct Connector {
     sync_pending_get: BranchQueue,
     sync_finished: BranchQueue,
     // Port/message management
-    ports: ConnectorPorts,
-    inbox: Inbox,
+    pub ports: ConnectorPorts,
+    pub public: ConnectorPublic,
 }
 
 struct TempCtx {}
@@ -307,7 +308,7 @@ impl Connector {
             sync_pending_get: BranchQueue::new(),
             sync_finished: BranchQueue::new(),
             ports: ConnectorPorts::new(owned_ports),
-            inbox: Inbox::new(),
+            public: ConnectorPublic::new(),
         }
     }
 
@@ -441,7 +442,7 @@ impl Connector {
             },
             RunResult::BranchPut(port_id, value_group) => {
                 // Branch performed a `put` on a particualar port.
-                let local_port_id = PortIdLocal{ id: port_id.0.u32_suffix };
+                let local_port_id = PortIdLocal{ index: port_id.0.u32_suffix };
                 let local_port_index = self.ports.get_port_index(local_port_id);
                 if local_port_index.is_none() {
                     todo!("handle case where port was received before (i.e. in ports_delta)")
@@ -470,9 +471,8 @@ impl Connector {
                     // Put in run results for thread to pick up and transfer to
                     // the correct connector inbox.
                     port_mapping.mark_definitive(branch.index, 1);
-                    let message = Message{
+                    let message = OutboxMessage {
                         sending_port: local_port_id,
-                        receiving_port: PortIdLocal::new_invalid(),
                         sender_prev_branch_id: BranchId::new_invalid(),
                         sender_cur_branch_id: branch.index,
                         message: value_group,
@@ -709,7 +709,7 @@ impl Connector {
 pub(crate) struct RunDeltaState {
     // Variables that allow the thread running the connector to pick up global
     // state changes and try to apply them.
-    pub outbox: Vec<Message>,
+    pub outbox: Vec<OutboxMessage>,
     pub new_connectors: Vec<Connector>,
     // Workspaces
     pub ports: Vec<PortIdLocal>,