diff --git a/test/test-network/conf/25-qdisc-cake.network b/test/test-network/conf/25-qdisc-cake.network
index b13720c6dd..6a1364214d 100644
--- a/test/test-network/conf/25-qdisc-cake.network
+++ b/test/test-network/conf/25-qdisc-cake.network
@@ -21,3 +21,5 @@ PriorityQueueingPreset=diffserv8
 FirewallMark=0xff00
 Wash=yes
 SplitGSO=yes
+RTTSec=1sec
+AckFilter=aggressive
diff --git a/test/test-network/systemd-networkd-tests.py b/test/test-network/systemd-networkd-tests.py
index 7da22349fa..e4e92d5a37 100755
--- a/test/test-network/systemd-networkd-tests.py
+++ b/test/test-network/systemd-networkd-tests.py
@@ -3485,6 +3485,8 @@ class NetworkdTCTests(unittest.TestCase, Utilities):
         self.assertIn('overhead 128', output)
         self.assertIn('mpu 20', output)
         self.assertIn('fwmark 0xff00', output)
+        self.assertIn('rtt 1s', output)
+        self.assertIn('ack-filter-aggressive', output)
 
     @expectedFailureIfModuleIsNotAvailable('sch_codel')
     def test_qdisc_codel(self):