1 files changed, 15 insertions, 0 deletions
diff --git a/src/main/java/derms/net/il/ControlMessage.java b/src/main/java/derms/net/il/ControlMessage.java
new file mode 100644
index 0000000..de69fe8
--- /dev/null
+++ b/src/main/java/derms/net/il/ControlMessage.java
@@ -0,0 +1,15 @@
+package derms.net.il;
+
+import java.io.Serializable;
+
+class ControlMessage implements Serializable {
+    final Type type;
+    final int id; // One greater than the sequence number of the highest sent data message.
+    final int ack; // Last in-sequence data message received by the transmitter of the message.
+
+    ControlMessage(Type type, int id, int ack) {
+        this.type = type;
+        this.id = id;
+        this.ack = ack;
+    }
+}