diff --git a/configs/csfb.yaml.in b/configs/csfb.yaml.in
index 293770074..dcc937c91 100644
--- a/configs/csfb.yaml.in
+++ b/configs/csfb.yaml.in
@@ -136,6 +136,7 @@ pgw:
       - 8.8.4.4
       - 2001:4860:4860::8888
       - 2001:4860:4860::8844
+    mtu: 1400
 pcrf:
     freeDiameter:
       identity: pcrf.localdomain
diff --git a/configs/installed.yaml.in b/configs/installed.yaml.in
index 487e8cc00..7aeaab577 100644
--- a/configs/installed.yaml.in
+++ b/configs/installed.yaml.in
@@ -383,6 +383,19 @@ sgw:
 #
 #  o GTP-U Server(all address avaiable)
 #    gtpu:
+#
+#  o Provide custom SGW GTP-U address to be advertised inside S1AP messages
+#    gtpu:
+#      addr: 10.4.128.21
+#      advertise_addr: 172.24.15.30
+#
+#    gtpu:
+#      addr: 10.4.128.21
+#      advertise_name: sgw1.epc.mnc001.mcc001.3gppnetwork.org
+#
+#    gtpu:
+#     dev: ens3
+#     advertise_name: sgw1.epc.mnc001.mcc001.3gppnetwork.org
 #    
     gtpu:
 
@@ -551,6 +564,17 @@ pgw:
       - 2001:4860:4860::8888
       - 2001:4860:4860::8844
 
+#
+#  <MTU Size>
+#
+#  o Provisioning a limit on the size of the packets sent by the MS
+#    to avoid packet fragmentation in the backbone network
+#    between the MS and the GGSN/PGW and/or across the (S)Gi reference point)
+#    when some of the backbone links does not support
+#    packets larger then 1500 octets
+#
+    mtu: 1400
+
 #
 #  <P-CSCF>
 #
diff --git a/configs/mnc3.yaml.in b/configs/mnc3.yaml.in
index 21e33be65..1970a0bc7 100644
--- a/configs/mnc3.yaml.in
+++ b/configs/mnc3.yaml.in
@@ -106,6 +106,7 @@ pgw:
       - 8.8.4.4
       - 2001:4860:4860::8888
       - 2001:4860:4860::8844
+    mtu: 1400
 pcrf:
     freeDiameter:
       identity: pcrf.localdomain
diff --git a/configs/open5gs/pgw.yaml.in b/configs/open5gs/pgw.yaml.in
index 48b984a23..9f90360fe 100644
--- a/configs/open5gs/pgw.yaml.in
+++ b/configs/open5gs/pgw.yaml.in
@@ -19,3 +19,4 @@ pgw:
       - 8.8.4.4
       - 2001:4860:4860::8888
       - 2001:4860:4860::8844
+    mtu: 1400
diff --git a/configs/simple.yaml.in b/configs/simple.yaml.in
index 22b7d2946..88812b33b 100644
--- a/configs/simple.yaml.in
+++ b/configs/simple.yaml.in
@@ -102,6 +102,7 @@ pgw:
       - 8.8.4.4
       - 2001:4860:4860::8888
       - 2001:4860:4860::8844
+    mtu: 1400
 pcrf:
     freeDiameter:
       identity: pcrf.localdomain
diff --git a/configs/split.yaml.in b/configs/split.yaml.in
index 4b43cb74d..5e083de76 100644
--- a/configs/split.yaml.in
+++ b/configs/split.yaml.in
@@ -100,6 +100,7 @@ pgw:
       - 8.8.4.4
       - 2001:4860:4860::8888
       - 2001:4860:4860::8844
+    mtu: 1400
 pcrf:
     freeDiameter:
       identity: pcrf.localdomain
diff --git a/configs/srslte.yaml.in b/configs/srslte.yaml.in
index 4717ba250..23edca8ed 100644
--- a/configs/srslte.yaml.in
+++ b/configs/srslte.yaml.in
@@ -102,6 +102,7 @@ pgw:
       - 8.8.4.4
       - 2001:4860:4860::8888
       - 2001:4860:4860::8844
+    mtu: 1400
 pcrf:
     freeDiameter:
       identity: pcrf.localdomain
diff --git a/configs/volte.yaml.in b/configs/volte.yaml.in
index 0e183cc89..167025b27 100644
--- a/configs/volte.yaml.in
+++ b/configs/volte.yaml.in
@@ -107,6 +107,7 @@ pgw:
       - 8.8.4.4
       - 2001:4860:4860::8888
       - 2001:4860:4860::8844
+    mtu: 1400
 #
 #  <P-CSCF>
 #
diff --git a/tests/csfb/mo-idle-test.c b/tests/csfb/mo-idle-test.c
index 1d10313d0..f369e3dce 100644
--- a/tests/csfb/mo-idle-test.c
+++ b/tests/csfb/mo-idle-test.c
@@ -52,13 +52,14 @@ static void test1_func(abts_case *tc, void *data)
         "6d6503657063066d 6e63303730066d63 633930310b336770 706e6574776f726b"
         "036f72670a010104 0509f1070926";
     const char *_initial_context_setup_request = 
-        "00090080d7000006 0000000200010008 000200010042000a 183d090000603d09"
-        "0000001800808800 0034008082450009 230f807f00000200 0000017327283f4c"
-        "6102074202490620 09f1070007004152 34c101090908696e 7465726e65740501"
-        "0a2d00025e06fefe e2e2030327228080 2110020000108106 0808080883060808"
-        "0404000d04080808 08000d0408080404 500bf609f1070002 01d20064c31309f1"
-        "0709262305f49ee8 8e64594964010100 6b00051c000e0000 00490020f9f4f80b"
-        "206c33ae286c6daf f4c253585174c3a0 a12a661967f5e1ba 0a686c8c";
+        "00090080dc000006 0000000200010008 000200010042000a 183d090000603d09"
+        "0000001800808d00 0034008087450009 230f807f00000200 000001782756d7d9"
+        "8002074202490620 09f1070007004652 34c101090908696e 7465726e65740501"
+        "0a2d00025e06fefe e2e2030327278080 2110020000108106 0808080883060808"
+        "0404000d04080808 08000d0408080404 0010020578500bf6 09f107000201ea00"
+        "1d661309f1070926 2305f49ee88e6459 49640101006b0005 1c000e0000004900"
+        "20f9f4f80b206c33 ae286c6daff4c253 585174c3a0a12a66 1967f5e1ba0a686c"
+        "8c";
     const char *_emm_information = 
         "000b403800000300 0000020001000800 020001001a002524 2751034124030761"
         "430f10004f007000 65006e0035004700 5347916051216124 63490100";
@@ -234,8 +235,8 @@ static void test1_func(abts_case *tc, void *data)
     OGS_HEX(_initial_context_setup_request,
             strlen(_initial_context_setup_request), tmp);
     ABTS_TRUE(tc, memcmp(recvbuf->data, tmp, 61) == 0);
-    ABTS_TRUE(tc, memcmp(recvbuf->data+65, tmp+65, 88) == 0);
-    ABTS_TRUE(tc, memcmp(recvbuf->data+157, tmp+157, 63) == 0);
+    ABTS_TRUE(tc, memcmp(recvbuf->data+65, tmp+65, 93) == 0);
+    ABTS_TRUE(tc, memcmp(recvbuf->data+162, tmp+162, 63) == 0);
     ogs_pkbuf_free(recvbuf);
 
     /* Send Initial Context Setup Response */