diff --git a/.gitignore b/.gitignore
index f16afd3e9872853782cdc698ce567780da54c857..d4f18656d89df0abc25f8d93dcf2336fce662355 100644
--- a/.gitignore
+++ b/.gitignore
@@ -3,4 +3,4 @@ swagger/__pycache__/
 src/__pycache__/
 venv/
 .env
-
+slice.db
diff --git a/src/mapper/main.py b/src/mapper/main.py
index 84be5720b12d6c4987094c1ca37b0e29c1cc568b..b7389356ba436ffa6a72afa04b9433eb8dfbe308 100644
--- a/src/mapper/main.py
+++ b/src/mapper/main.py
@@ -43,7 +43,6 @@ def mapper(ietf_intent):
 
         # Extract Service Level Objectives (SLOs) from the intent
         slos = ietf_intent["ietf-network-slice-service:network-slice-services"]["slo-sle-templates"]["slo-sle-template"][0]["slo-policy"]["metric-bound"]
-        print(f"SLOs: {slos}")
         if slos:
             # Find candidate NRPs that can meet the SLO requirements
             candidates = [
diff --git a/src/realizer/main.py b/src/realizer/main.py
index 2bd898363176c2931629e32314aad15a59a22274..e1f08a0ae6c6c899f6d7784cee1fd50e69a5eb45 100644
--- a/src/realizer/main.py
+++ b/src/realizer/main.py
@@ -12,10 +12,12 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-# This file is an original contribution from Telefonica Innovación Digital S.L.
+# This file includes original contributions from Telefonica Innovación Digital S.L.
 
+import logging
 from .select_way import select_way
 from .nrp_handler import nrp_handler
+from src.utils.safe_get import safe_get
 
 def realizer(ietf_intent, need_nrp=False, order=None, nrp=None, controller_type=None, response=None):
     """
@@ -37,7 +39,6 @@ def realizer(ietf_intent, need_nrp=False, order=None, nrp=None, controller_type=
         return nrp_view
     else:
         # Select slice service method
-        way = ietf_intent["ietf-network-slice-service:network-slice-services"]["slice-service"][0]["service-tags"]["tag-type"]["value"]
-        way = "L2VPN"
+        way = safe_get(ietf_intent, ['ietf-network-slice-service:network-slice-services', 'slice-service', 0, 'service-tags', 'tag-type', 0, 'tag-type-value', 0])
         request = select_way(controller=controller_type, way=way, ietf_intent=ietf_intent, response=response)
         return request
diff --git a/src/realizer/tfs/main.py b/src/realizer/tfs/main.py
index 9e1233eb6ba593ee861ffc612d5e9134f40648b1..2975127272d181620d623b33092f70e158f015e5 100644
--- a/src/realizer/tfs/main.py
+++ b/src/realizer/tfs/main.py
@@ -19,11 +19,11 @@ from .service_types.tfs_l2vpn import tfs_l2vpn
 from .service_types.tfs_l3vpn import tfs_l3vpn
 
 def tfs(ietf_intent, way=None, response=None):
-    if way == "L2VPN":
+    if way == "L2":
         realizing_request = tfs_l2vpn(ietf_intent, response)
-    elif way == "L3VPN":
+    elif way == "L3":
         realizing_request = tfs_l3vpn(ietf_intent, response)
     else:
-        logging.warning(f"Unsupported way: {way}. Defaulting to L2VPN realization.")
+        logging.warning(f"Unsupported way: {way}. Defaulting to L2 realization.")
         realizing_request = tfs_l2vpn(ietf_intent, response)
     return realizing_request
\ No newline at end of file
diff --git a/src/templates/ietf_template_empty.json b/src/templates/ietf_template_empty.json
index cdaf66cdad3fbd7f01c09a7987cf8729600952b0..c484a4a2991e0b34ce691ee14125c2fddb00fa41 100644
--- a/src/templates/ietf_template_empty.json
+++ b/src/templates/ietf_template_empty.json
@@ -29,10 +29,14 @@
            "id":"5GSliceMapping",
            "description":"example 5G Slice mapping",
            "service-tags":{
-              "tag-type":{
-                 "tag-type":"",
-                 "value":""
+            "tag-type": [
+              {
+                "tag-type": "",
+                "tag-type-value": [
+                  ""
+                ]
               }
+            ]
            },
            "slo-sle-policy":{
               "slo-sle-template":""
diff --git a/src/utils/safe_get.py b/src/utils/safe_get.py
new file mode 100644
index 0000000000000000000000000000000000000000..a12d885dbe770800165eee603a45c2fa716041a7
--- /dev/null
+++ b/src/utils/safe_get.py
@@ -0,0 +1,26 @@
+# Copyright 2022-2025 ETSI SDG TeraFlowSDN (TFS) (https://tfs.etsi.org/)
+
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+
+#     http://www.apache.org/licenses/LICENSE-2.0
+
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# This file is an original contribution from Telefonica Innovación Digital S.L.
+
+def safe_get(dct, keys):
+    """Safely get a nested value from a dictionary or list."""
+    for key in keys:
+        if isinstance(dct, dict) and key in dct:
+            dct = dct[key]
+        elif isinstance(dct, list) and isinstance(key, int) and key < len(dct):
+            dct = dct[key]
+        else:
+            return None
+    return dct