diff --git a/core/federated/RTI/rti_remote.c b/core/federated/RTI/rti_remote.c
index b60736bda..f3d540115 100644
--- a/core/federated/RTI/rti_remote.c
+++ b/core/federated/RTI/rti_remote.c
@@ -377,7 +377,7 @@ void handle_port_absent_message(federate_info_t *sending_federate, unsigned char
 }
 
 void handle_timed_message(federate_info_t *sending_federate, unsigned char *buffer) {
-    size_t header_size = 1 + sizeof(uint16_t) + sizeof(uint16_t) + sizeof(int32_t)
+    size_t header_size = 1 + sizeof(uint16_t) + sizeof(uint16_t) + sizeof(uint32_t)
             + sizeof(int64_t) + sizeof(uint32_t);
     // Read the header, minus the first byte which has already been read.
     read_from_socket_fail_on_error(
diff --git a/core/federated/federate.c b/core/federated/federate.c
index 57ff1c750..46c5b89ed 100644
--- a/core/federated/federate.c
+++ b/core/federated/federate.c
@@ -528,7 +528,7 @@ static int handle_tagged_message(int* socket, int fed_id) {
     _lf_get_environments(&env);
 
     // Read the header which contains the timestamp.
-    size_t bytes_to_read = sizeof(uint16_t) + sizeof(uint16_t) + sizeof(int32_t)
+    size_t bytes_to_read = sizeof(uint16_t) + sizeof(uint16_t) + sizeof(uint32_t)
             + sizeof(instant_t) + sizeof(microstep_t);
     unsigned char buffer[bytes_to_read];
     if (read_from_socket_close_on_error(socket, bytes_to_read, buffer)) {
@@ -2653,7 +2653,7 @@ int lf_send_tagged_message(environment_t* env,
     buffer_head += sizeof(uint16_t);
 
     // The next four bytes are the message length.
-    encode_int32((int32_t)length, &(header_buffer[buffer_head]));
+    encode_uint32((uint32_t)length, &(header_buffer[buffer_head]));
     buffer_head += sizeof(int32_t);
 
     // Apply the additional delay to the current tag and use that as the intended
diff --git a/core/federated/network/net_util.c b/core/federated/network/net_util.c
index 813e5cd07..6bc3fd0d7 100644
--- a/core/federated/network/net_util.c
+++ b/core/federated/network/net_util.c
@@ -403,7 +403,7 @@ void extract_header(
     // printf("DEBUG: Message for port %d of federate %d.\n", *port_id, *federate_id);
 
     // The next four bytes are the message length.
-    int32_t local_length_signed = extract_int32(&(buffer[sizeof(uint16_t) + sizeof(uint16_t)]));
+    uint32_t local_length_signed = extract_uint32(&(buffer[sizeof(uint16_t) + sizeof(uint16_t)]));
     if (local_length_signed < 0) {
         lf_print_error_and_exit(
             "Received an invalid message length (%d) from federate %d.",
diff --git a/include/core/federated/network/net_common.h b/include/core/federated/network/net_common.h
index 9ea720fd7..8f2bc3f5a 100644
--- a/include/core/federated/network/net_common.h
+++ b/include/core/federated/network/net_common.h
@@ -386,7 +386,7 @@ THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  * Byte identifying a timestamped message to forward to another federate.
  * The next two bytes will be the ID of the destination reactor port.
  * The next two bytes are the destination federate ID.
- * The four bytes after that will be the length of the message.
+ * The four bytes after that will be the length of the message (as an unsigned 32-bit int).
  * The next eight bytes will be the timestamp of the message.
  * The next four bytes will be the microstep of the message.
  * The remaining bytes are the message.