diff --git a/src/core/openthread-core-default-config.h b/src/core/openthread-core-default-config.h
index 8bd0dea49..92b9578c1 100644
--- a/src/core/openthread-core-default-config.h
+++ b/src/core/openthread-core-default-config.h
@@ -1776,4 +1776,35 @@
 #define OPENTHREAD_CONFIG_POSIX_SETTINGS_PATH "tmp"
 #endif
 
+/**
+ * @def OPENTHREAD_CONFIG_FAILED_CHILD_TRANSMISSIONS
+ *
+ * This setting configures the number of consecutive MCPS.DATA-Confirms having Status NO_ACK
+ * that cause a Child-to-Parent link to be considered broken.
+ *
+ */
+#ifndef OPENTHREAD_CONFIG_FAILED_CHILD_TRANSMISSIONS
+#define OPENTHREAD_CONFIG_FAILED_CHILD_TRANSMISSIONS 4
+#endif
+
+/**
+ * @def OPENTHREAD_CONFIG_MINIMUM_POLL_PERIOD
+ *
+ * This setting configures the minimum poll period in milliseconds.
+ *
+ */
+#ifndef OPENTHREAD_CONFIG_MINIMUM_POLL_PERIOD
+#define OPENTHREAD_CONFIG_MINIMUM_POLL_PERIOD 10
+#endif
+
+/**
+ * @def OPENTHREAD_CONFIG_RETX_POLL_PERIOD
+ *
+ * This setting configures the retx poll period in milliseconds.
+ *
+ */
+#ifndef OPENTHREAD_CONFIG_RETX_POLL_PERIOD
+#define OPENTHREAD_CONFIG_RETX_POLL_PERIOD 1000
+#endif
+
 #endif // OPENTHREAD_CORE_DEFAULT_CONFIG_H_
diff --git a/src/core/thread/data_poll_manager.hpp b/src/core/thread/data_poll_manager.hpp
index 03b3d1dd6..aa9d11db6 100644
--- a/src/core/thread/data_poll_manager.hpp
+++ b/src/core/thread/data_poll_manager.hpp
@@ -196,16 +196,17 @@ private:
     enum // Poll period under different conditions (in milliseconds).
     {
         kAttachDataPollPeriod   = OPENTHREAD_CONFIG_ATTACH_DATA_POLL_PERIOD, ///< Poll period during attach.
-        kRetxPollPeriod         = 1000,                                      ///< Poll retx period due to tx failure.
+        kRetxPollPeriod         = OPENTHREAD_CONFIG_RETX_POLL_PERIOD,        ///< Poll retx period due to tx failure.
         kNoBufferRetxPollPeriod = 200,                                       ///< Poll retx due to no buffer space.
         kFastPollPeriod         = 188,                                       ///< Period used for fast polls.
-        kMinPollPeriod          = 10,                                        ///< Minimum allowed poll period.
+        kMinPollPeriod          = OPENTHREAD_CONFIG_MINIMUM_POLL_PERIOD,     ///< Minimum allowed poll period.
     };
 
     enum
     {
         kQuickPollsAfterTimeout = 5, ///< Maximum number of quick data poll tx in case of back-to-back poll timeouts.
-        kMaxPollRetxAttempts    = 5, ///< Maximum number of retransmit attempts of data poll (mac data request).
+        kMaxPollRetxAttempts = OPENTHREAD_CONFIG_FAILED_CHILD_TRANSMISSIONS, ///< Maximum number of retransmit attempts
+                                                                             ///< of data poll (mac data request).
     };
 
     enum PollPeriodSelector
diff --git a/src/core/thread/mle_constants.hpp b/src/core/thread/mle_constants.hpp
index 3c1c7b1ac..bdb3800da 100644
--- a/src/core/thread/mle_constants.hpp
+++ b/src/core/thread/mle_constants.hpp
@@ -48,7 +48,7 @@ enum
 {
     kMaxChildren               = OPENTHREAD_CONFIG_MAX_CHILDREN,
     kMaxChildKeepAliveAttempts = 4, ///< Maximum keep alive attempts before attempting to reattach to a new Parent
-    kFailedChildTransmissions  = 4, ///< FAILED_CHILD_TRANSMISSIONS
+    kFailedChildTransmissions  = OPENTHREAD_CONFIG_FAILED_CHILD_TRANSMISSIONS, ///< FAILED_CHILD_TRANSMISSIONS
 };
 
 /**
@@ -74,7 +74,13 @@ enum
     kMaxChildIdRequestTimeout       = 5000,  ///< Maximum delay for receiving a Child ID Request
     kMaxChildUpdateResponseTimeout  = 2000,  ///< Maximum delay for receiving a Child Update Response
     kMaxLinkRequestTimeout          = 2000,  ///< Maximum delay for receiving a Link Accept
-    kMinTimeout = (((kMaxChildKeepAliveAttempts + 1) * kUnicastRetransmissionDelay) / 1000), ///< Minimum timeout(s)
+    kMinTimeoutKeepAlive            = (((kMaxChildKeepAliveAttempts + 1) * kUnicastRetransmissionDelay) /
+                            1000), ///< Minimum timeout(s) for keep alive
+    kMinTimeoutDataPoll             = (OPENTHREAD_CONFIG_MINIMUM_POLL_PERIOD +
+                           OPENTHREAD_CONFIG_FAILED_CHILD_TRANSMISSIONS * OPENTHREAD_CONFIG_RETX_POLL_PERIOD) /
+                          1000, ///< Minimum timeout(s) for data poll
+    kMinTimeout = (kMinTimeoutKeepAlive >= kMinTimeoutDataPoll ? kMinTimeoutKeepAlive
+                                                               : kMinTimeoutDataPoll), ///< Minimum timeout(s)
 };
 
 enum
diff --git a/tests/scripts/thread-cert/Cert_5_1_02_ChildAddressTimeout.py b/tests/scripts/thread-cert/Cert_5_1_02_ChildAddressTimeout.py
index e130ae350..bc77d06e2 100755
--- a/tests/scripts/thread-cert/Cert_5_1_02_ChildAddressTimeout.py
+++ b/tests/scripts/thread-cert/Cert_5_1_02_ChildAddressTimeout.py
@@ -65,13 +65,13 @@ class Cert_5_1_02_ChildAddressTimeout(unittest.TestCase):
 
         self.nodes[ED].set_panid(0xface)
         self.nodes[ED].set_mode('rsn')
-        self.nodes[ED].set_timeout(3)
+        self.nodes[ED].set_timeout(config.DEFAULT_CHILD_TIMEOUT)
         self.nodes[ED].add_whitelist(self.nodes[ROUTER].get_addr64())
         self.nodes[ED].enable_whitelist()
 
         self.nodes[SED].set_panid(0xface)
         self.nodes[SED].set_mode('sn')
-        self.nodes[SED].set_timeout(3)
+        self.nodes[SED].set_timeout(config.DEFAULT_CHILD_TIMEOUT)
         self.nodes[SED].add_whitelist(self.nodes[ROUTER].get_addr64())
         self.nodes[SED].enable_whitelist()
 
diff --git a/tests/scripts/thread-cert/Cert_5_1_07_MaxChildCount.py b/tests/scripts/thread-cert/Cert_5_1_07_MaxChildCount.py
index d6833e71a..820eb04fe 100755
--- a/tests/scripts/thread-cert/Cert_5_1_07_MaxChildCount.py
+++ b/tests/scripts/thread-cert/Cert_5_1_07_MaxChildCount.py
@@ -66,7 +66,7 @@ class Cert_5_1_07_MaxChildCount(unittest.TestCase):
             self.nodes[i].add_whitelist(self.nodes[ROUTER].get_addr64())
             self.nodes[ROUTER].add_whitelist(self.nodes[i].get_addr64())
             self.nodes[i].enable_whitelist()
-            self.nodes[i].set_timeout(3)
+            self.nodes[i].set_timeout(config.DEFAULT_CHILD_TIMEOUT)
 
     def tearDown(self):
         for node in list(self.nodes.values()):
diff --git a/tests/scripts/thread-cert/Cert_5_3_02_RealmLocal.py b/tests/scripts/thread-cert/Cert_5_3_02_RealmLocal.py
index 22221bfbc..aa2e77add 100755
--- a/tests/scripts/thread-cert/Cert_5_3_02_RealmLocal.py
+++ b/tests/scripts/thread-cert/Cert_5_3_02_RealmLocal.py
@@ -70,7 +70,7 @@ class Cert_5_3_2_RealmLocal(unittest.TestCase):
         self.nodes[SED1].set_mode('sn')
         self.nodes[SED1].add_whitelist(self.nodes[DUT_ROUTER2].get_addr64())
         self.nodes[SED1].enable_whitelist()
-        self.nodes[SED1].set_timeout(3)
+        self.nodes[SED1].set_timeout(config.DEFAULT_CHILD_TIMEOUT)
 
     def tearDown(self):
         for node in list(self.nodes.values()):
diff --git a/tests/scripts/thread-cert/Cert_5_3_09_AddressQuery.py b/tests/scripts/thread-cert/Cert_5_3_09_AddressQuery.py
index 9a913c911..3144c884a 100755
--- a/tests/scripts/thread-cert/Cert_5_3_09_AddressQuery.py
+++ b/tests/scripts/thread-cert/Cert_5_3_09_AddressQuery.py
@@ -80,7 +80,7 @@ class Cert_5_3_09_AddressQuery(unittest.TestCase):
         self.nodes[SED1].set_panid(0xface)
         self.nodes[SED1].set_mode('s')
         self.nodes[SED1].add_whitelist(self.nodes[DUT_ROUTER2].get_addr64())
-        self.nodes[SED1].set_timeout(3)
+        self.nodes[SED1].set_timeout(config.DEFAULT_CHILD_TIMEOUT)
         self.nodes[SED1].enable_whitelist()
 
     def tearDown(self):
diff --git a/tests/scripts/thread-cert/Cert_5_6_01_NetworkDataRegisterBeforeAttachLeader.py b/tests/scripts/thread-cert/Cert_5_6_01_NetworkDataRegisterBeforeAttachLeader.py
index 9b52d7190..5142f94c7 100755
--- a/tests/scripts/thread-cert/Cert_5_6_01_NetworkDataRegisterBeforeAttachLeader.py
+++ b/tests/scripts/thread-cert/Cert_5_6_01_NetworkDataRegisterBeforeAttachLeader.py
@@ -70,7 +70,7 @@ class Cert_5_6_1_NetworkDataLeaderAsBr(unittest.TestCase):
         self.nodes[SED1].set_mode('s')
         self.nodes[SED1].add_whitelist(self.nodes[ROUTER].get_addr64())
         self.nodes[SED1].enable_whitelist()
-        self.nodes[SED1].set_timeout(3)
+        self.nodes[SED1].set_timeout(config.DEFAULT_CHILD_TIMEOUT)
 
     def tearDown(self):
         for node in list(self.nodes.values()):
diff --git a/tests/scripts/thread-cert/Cert_5_6_02_NetworkDataRegisterBeforeAttachRouter.py b/tests/scripts/thread-cert/Cert_5_6_02_NetworkDataRegisterBeforeAttachRouter.py
index 6f8a17c74..751c1bddf 100755
--- a/tests/scripts/thread-cert/Cert_5_6_02_NetworkDataRegisterBeforeAttachRouter.py
+++ b/tests/scripts/thread-cert/Cert_5_6_02_NetworkDataRegisterBeforeAttachRouter.py
@@ -70,7 +70,7 @@ class Cert_5_6_2_NetworkDataRouterAsBr(unittest.TestCase):
         self.nodes[SED1].set_mode('s')
         self.nodes[SED1].add_whitelist(self.nodes[LEADER].get_addr64())
         self.nodes[SED1].enable_whitelist()
-        self.nodes[SED1].set_timeout(3)
+        self.nodes[SED1].set_timeout(config.DEFAULT_CHILD_TIMEOUT)
 
     def tearDown(self):
         for node in list(self.nodes.values()):
diff --git a/tests/scripts/thread-cert/Cert_5_6_03_NetworkDataRegisterAfterAttachLeader.py b/tests/scripts/thread-cert/Cert_5_6_03_NetworkDataRegisterAfterAttachLeader.py
index 81d7d680c..26e9cfef2 100755
--- a/tests/scripts/thread-cert/Cert_5_6_03_NetworkDataRegisterAfterAttachLeader.py
+++ b/tests/scripts/thread-cert/Cert_5_6_03_NetworkDataRegisterAfterAttachLeader.py
@@ -70,7 +70,7 @@ class Cert_5_6_3_NetworkDataRegisterAfterAttachLeader(unittest.TestCase):
         self.nodes[SED1].set_mode('s')
         self.nodes[SED1].add_whitelist(self.nodes[ROUTER].get_addr64())
         self.nodes[SED1].enable_whitelist()
-        self.nodes[SED1].set_timeout(3)
+        self.nodes[SED1].set_timeout(config.DEFAULT_CHILD_TIMEOUT)
 
     def tearDown(self):
         for node in list(self.nodes.values()):
diff --git a/tests/scripts/thread-cert/Cert_5_6_04_NetworkDataRegisterAfterAttachRouter.py b/tests/scripts/thread-cert/Cert_5_6_04_NetworkDataRegisterAfterAttachRouter.py
index 900d27e5b..4c049e138 100755
--- a/tests/scripts/thread-cert/Cert_5_6_04_NetworkDataRegisterAfterAttachRouter.py
+++ b/tests/scripts/thread-cert/Cert_5_6_04_NetworkDataRegisterAfterAttachRouter.py
@@ -70,7 +70,7 @@ class Cert_5_6_4_NetworkDataRegisterAfterAttachRouter(unittest.TestCase):
         self.nodes[SED1].set_mode('s')
         self.nodes[SED1].add_whitelist(self.nodes[ROUTER].get_addr64())
         self.nodes[SED1].enable_whitelist()
-        self.nodes[SED1].set_timeout(3)
+        self.nodes[SED1].set_timeout(config.DEFAULT_CHILD_TIMEOUT)
 
     def tearDown(self):
         for node in list(self.nodes.values()):
diff --git a/tests/scripts/thread-cert/Cert_5_6_05_NetworkDataRegisterAfterAttachRouter.py b/tests/scripts/thread-cert/Cert_5_6_05_NetworkDataRegisterAfterAttachRouter.py
index 00a673b8e..38c01dd65 100755
--- a/tests/scripts/thread-cert/Cert_5_6_05_NetworkDataRegisterAfterAttachRouter.py
+++ b/tests/scripts/thread-cert/Cert_5_6_05_NetworkDataRegisterAfterAttachRouter.py
@@ -70,7 +70,7 @@ class Cert_5_6_5_NetworkDataRegisterAfterAttachRouter(unittest.TestCase):
         self.nodes[SED1].set_mode('s')
         self.nodes[SED1].add_whitelist(self.nodes[ROUTER].get_addr64())
         self.nodes[SED1].enable_whitelist()
-        self.nodes[SED1].set_timeout(3)
+        self.nodes[SED1].set_timeout(config.DEFAULT_CHILD_TIMEOUT)
 
     def tearDown(self):
         for node in list(self.nodes.values()):
diff --git a/tests/scripts/thread-cert/Cert_5_6_06_NetworkDataExpiration.py b/tests/scripts/thread-cert/Cert_5_6_06_NetworkDataExpiration.py
index a67d093ba..42c898557 100755
--- a/tests/scripts/thread-cert/Cert_5_6_06_NetworkDataExpiration.py
+++ b/tests/scripts/thread-cert/Cert_5_6_06_NetworkDataExpiration.py
@@ -70,7 +70,7 @@ class Cert_5_6_6_NetworkDataExpiration(unittest.TestCase):
         self.nodes[SED1].set_mode('s')
         self.nodes[SED1].add_whitelist(self.nodes[ROUTER].get_addr64())
         self.nodes[SED1].enable_whitelist()
-        self.nodes[SED1].set_timeout(3)
+        self.nodes[SED1].set_timeout(config.DEFAULT_CHILD_TIMEOUT)
 
     def tearDown(self):
         for node in list(self.nodes.values()):
diff --git a/tests/scripts/thread-cert/Cert_5_6_09_NetworkDataForwarding.py b/tests/scripts/thread-cert/Cert_5_6_09_NetworkDataForwarding.py
index 381d2f94d..4cc4c763e 100755
--- a/tests/scripts/thread-cert/Cert_5_6_09_NetworkDataForwarding.py
+++ b/tests/scripts/thread-cert/Cert_5_6_09_NetworkDataForwarding.py
@@ -78,7 +78,7 @@ class Cert_5_6_9_NetworkDataForwarding(unittest.TestCase):
         self.nodes[SED].set_mode('s')
         self.nodes[SED].add_whitelist(self.nodes[ROUTER1].get_addr64())
         self.nodes[SED].enable_whitelist()
-        self.nodes[SED].set_timeout(3)
+        self.nodes[SED].set_timeout(config.DEFAULT_CHILD_TIMEOUT)
 
     def tearDown(self):
         for node in list(self.nodes.values()):
diff --git a/tests/scripts/thread-cert/Cert_6_5_01_ChildResetSynchronize.py b/tests/scripts/thread-cert/Cert_6_5_01_ChildResetSynchronize.py
index 6631f63c4..dd20110af 100755
--- a/tests/scripts/thread-cert/Cert_6_5_01_ChildResetSynchronize.py
+++ b/tests/scripts/thread-cert/Cert_6_5_01_ChildResetSynchronize.py
@@ -51,7 +51,7 @@ class Cert_6_5_1_ChildResetSynchronize(unittest.TestCase):
 
         self.nodes[ED].set_panid(0xface)
         self.nodes[ED].set_mode('rsn')
-        self.nodes[ED].set_timeout(3)
+        self.nodes[ED].set_timeout(config.DEFAULT_CHILD_TIMEOUT)
         self._setUpEd()
 
     def _setUpEd(self):
diff --git a/tests/scripts/thread-cert/Cert_7_1_01_BorderRouterAsLeader.py b/tests/scripts/thread-cert/Cert_7_1_01_BorderRouterAsLeader.py
index cdd2eeb07..eaba7fcaa 100755
--- a/tests/scripts/thread-cert/Cert_7_1_01_BorderRouterAsLeader.py
+++ b/tests/scripts/thread-cert/Cert_7_1_01_BorderRouterAsLeader.py
@@ -65,7 +65,7 @@ class Cert_7_1_1_BorderRouterAsLeader(unittest.TestCase):
         self.nodes[SED1].set_mode('s')
         self.nodes[SED1].add_whitelist(self.nodes[LEADER].get_addr64())
         self.nodes[SED1].enable_whitelist()
-        self.nodes[SED1].set_timeout(3)
+        self.nodes[SED1].set_timeout(config.DEFAULT_CHILD_TIMEOUT)
 
         self.nodes[ED1].set_panid(0xface)
         self.nodes[ED1].set_mode('rsn')
diff --git a/tests/scripts/thread-cert/Cert_7_1_02_BorderRouterAsRouter.py b/tests/scripts/thread-cert/Cert_7_1_02_BorderRouterAsRouter.py
index aef3a6ae2..4eef8bcd5 100755
--- a/tests/scripts/thread-cert/Cert_7_1_02_BorderRouterAsRouter.py
+++ b/tests/scripts/thread-cert/Cert_7_1_02_BorderRouterAsRouter.py
@@ -70,7 +70,7 @@ class Cert_7_1_2_BorderRouterAsRouter(unittest.TestCase):
         self.nodes[SED2].set_mode('s')
         self.nodes[SED2].add_whitelist(self.nodes[ROUTER].get_addr64())
         self.nodes[SED2].enable_whitelist()
-        self.nodes[SED2].set_timeout(3)
+        self.nodes[SED2].set_timeout(config.DEFAULT_CHILD_TIMEOUT)
 
     def tearDown(self):
         for node in list(self.nodes.values()):
diff --git a/tests/scripts/thread-cert/Cert_7_1_03_BorderRouterAsLeader.py b/tests/scripts/thread-cert/Cert_7_1_03_BorderRouterAsLeader.py
index 5618bfca3..daf6622ef 100755
--- a/tests/scripts/thread-cert/Cert_7_1_03_BorderRouterAsLeader.py
+++ b/tests/scripts/thread-cert/Cert_7_1_03_BorderRouterAsLeader.py
@@ -65,7 +65,7 @@ class Cert_7_1_3_BorderRouterAsLeader(unittest.TestCase):
         self.nodes[SED1].set_mode('s')
         self.nodes[SED1].add_whitelist(self.nodes[LEADER].get_addr64())
         self.nodes[SED1].enable_whitelist()
-        self.nodes[SED1].set_timeout(3)
+        self.nodes[SED1].set_timeout(config.DEFAULT_CHILD_TIMEOUT)
 
         self.nodes[ED1].set_panid(0xface)
         self.nodes[ED1].set_mode('rsn')
diff --git a/tests/scripts/thread-cert/Cert_7_1_04_BorderRouterAsRouter.py b/tests/scripts/thread-cert/Cert_7_1_04_BorderRouterAsRouter.py
index 817295128..d07f0dd11 100755
--- a/tests/scripts/thread-cert/Cert_7_1_04_BorderRouterAsRouter.py
+++ b/tests/scripts/thread-cert/Cert_7_1_04_BorderRouterAsRouter.py
@@ -70,7 +70,7 @@ class Cert_7_1_4_BorderRouterAsRouter(unittest.TestCase):
         self.nodes[SED2].set_mode('s')
         self.nodes[SED2].add_whitelist(self.nodes[ROUTER].get_addr64())
         self.nodes[SED2].enable_whitelist()
-        self.nodes[SED2].set_timeout(3)
+        self.nodes[SED2].set_timeout(config.DEFAULT_CHILD_TIMEOUT)
 
     def tearDown(self):
         for node in list(self.nodes.values()):
diff --git a/tests/scripts/thread-cert/Cert_7_1_05_BorderRouterAsRouter.py b/tests/scripts/thread-cert/Cert_7_1_05_BorderRouterAsRouter.py
index 53f0d552b..5800c94bb 100755
--- a/tests/scripts/thread-cert/Cert_7_1_05_BorderRouterAsRouter.py
+++ b/tests/scripts/thread-cert/Cert_7_1_05_BorderRouterAsRouter.py
@@ -70,7 +70,7 @@ class Cert_7_1_5_BorderRouterAsRouter(unittest.TestCase):
         self.nodes[SED2].set_mode('s')
         self.nodes[SED2].add_whitelist(self.nodes[ROUTER].get_addr64())
         self.nodes[SED2].enable_whitelist()
-        self.nodes[SED2].set_timeout(3)
+        self.nodes[SED2].set_timeout(config.DEFAULT_CHILD_TIMEOUT)
 
     def tearDown(self):
         for node in list(self.nodes.values()):
diff --git a/tests/scripts/thread-cert/Cert_9_2_08_PersistentDatasets.py b/tests/scripts/thread-cert/Cert_9_2_08_PersistentDatasets.py
index 4bb5fff0a..f07e8bff1 100755
--- a/tests/scripts/thread-cert/Cert_9_2_08_PersistentDatasets.py
+++ b/tests/scripts/thread-cert/Cert_9_2_08_PersistentDatasets.py
@@ -92,12 +92,12 @@ class Cert_9_2_8_PersistentDatasets(unittest.TestCase):
     def _setUpEd(self):
         self.nodes[ED].add_whitelist(self.nodes[LEADER].get_addr64())
         self.nodes[ED].enable_whitelist()
-        self.nodes[ED].set_timeout(3)
+        self.nodes[ED].set_timeout(config.DEFAULT_CHILD_TIMEOUT)
 
     def _setUpSed(self):
         self.nodes[SED].add_whitelist(self.nodes[LEADER].get_addr64())
         self.nodes[SED].enable_whitelist()
-        self.nodes[SED].set_timeout(3)
+        self.nodes[SED].set_timeout(config.DEFAULT_CHILD_TIMEOUT)
 
     def tearDown(self):
         for node in list(self.nodes.values()):
diff --git a/tests/scripts/thread-cert/Cert_9_2_10_PendingPartition.py b/tests/scripts/thread-cert/Cert_9_2_10_PendingPartition.py
index ee0107973..557fbac14 100755
--- a/tests/scripts/thread-cert/Cert_9_2_10_PendingPartition.py
+++ b/tests/scripts/thread-cert/Cert_9_2_10_PendingPartition.py
@@ -88,7 +88,7 @@ class Cert_9_2_10_PendingPartition(unittest.TestCase):
         self.nodes[SED1].set_mode('s')
         self.nodes[SED1].add_whitelist(self.nodes[ROUTER1].get_addr64())
         self.nodes[SED1].enable_whitelist()
-        self.nodes[SED1].set_timeout(3)
+        self.nodes[SED1].set_timeout(config.DEFAULT_CHILD_TIMEOUT)
 
     def tearDown(self):
         for node in list(self.nodes.values()):
diff --git a/tests/scripts/thread-cert/Cert_9_2_11_MasterKey.py b/tests/scripts/thread-cert/Cert_9_2_11_MasterKey.py
index 8d863bb54..3eb9eb3e5 100755
--- a/tests/scripts/thread-cert/Cert_9_2_11_MasterKey.py
+++ b/tests/scripts/thread-cert/Cert_9_2_11_MasterKey.py
@@ -89,7 +89,7 @@ class Cert_9_2_11_MasterKey(unittest.TestCase):
         self.nodes[SED1].set_mode('s')
         self.nodes[SED1].add_whitelist(self.nodes[ROUTER1].get_addr64())
         self.nodes[SED1].enable_whitelist()
-        self.nodes[SED1].set_timeout(3)
+        self.nodes[SED1].set_timeout(config.DEFAULT_CHILD_TIMEOUT)
 
     def tearDown(self):
         for node in list(self.nodes.values()):
diff --git a/tests/scripts/thread-cert/Cert_9_2_17_Orphan.py b/tests/scripts/thread-cert/Cert_9_2_17_Orphan.py
index 201b75918..d41199113 100755
--- a/tests/scripts/thread-cert/Cert_9_2_17_Orphan.py
+++ b/tests/scripts/thread-cert/Cert_9_2_17_Orphan.py
@@ -66,7 +66,7 @@ class Cert_9_2_17_Orphan(unittest.TestCase):
         self.nodes[ED1].set_panid(PANID_INIT)
         self.nodes[ED1].add_whitelist(self.nodes[LEADER1].get_addr64())
         self.nodes[ED1].enable_whitelist()
-        self.nodes[ED1].set_timeout(3)
+        self.nodes[ED1].set_timeout(config.DEFAULT_CHILD_TIMEOUT)
 
     def tearDown(self):
         for node in list(self.nodes.values()):
diff --git a/tests/scripts/thread-cert/Cert_9_2_18_RollBackActiveTimestamp.py b/tests/scripts/thread-cert/Cert_9_2_18_RollBackActiveTimestamp.py
index f9cf62a8e..873140247 100755
--- a/tests/scripts/thread-cert/Cert_9_2_18_RollBackActiveTimestamp.py
+++ b/tests/scripts/thread-cert/Cert_9_2_18_RollBackActiveTimestamp.py
@@ -98,7 +98,7 @@ class Cert_9_2_18_RollBackActiveTimestamp(unittest.TestCase):
         self.nodes[SED1].set_panid(PANID_INIT)
         self.nodes[SED1].add_whitelist(self.nodes[ROUTER1].get_addr64())
         self.nodes[SED1].enable_whitelist()
-        self.nodes[SED1].set_timeout(3)
+        self.nodes[SED1].set_timeout(config.DEFAULT_CHILD_TIMEOUT)
 
     def tearDown(self):
         for node in list(self.nodes.values()):
diff --git a/tests/scripts/thread-cert/config.py b/tests/scripts/thread-cert/config.py
index 0d639c0f0..373c01b51 100644
--- a/tests/scripts/thread-cert/config.py
+++ b/tests/scripts/thread-cert/config.py
@@ -68,8 +68,9 @@ INFINITE_COST_TIMEOUT = 90
 MAX_ADVERTISEMENT_INTERVAL = 32
 MLE_END_DEVICE_TIMEOUT = 100
 
-AQ_TIMEOUT = 3 
+AQ_TIMEOUT = 3
 ADDRESS_QUERY_INITIAL_RETRY_DELAY = 15
+DEFAULT_CHILD_TIMEOUT = 6
 
 VIRTUAL_TIME = bool(os.getenv('VIRTUAL_TIME', False))