diff --git a/clmctest/monitoring/E2EAggregator.py b/clmctest/monitoring/E2EAggregator.py
index d0ee8cba1c459211eccaf0bd2025de16ef79693e..372ec3c5b6002bbe3c7cc1fcdc45e363596fd0cd 100644
--- a/clmctest/monitoring/E2EAggregator.py
+++ b/clmctest/monitoring/E2EAggregator.py
@@ -82,6 +82,7 @@ class Aggregator(Thread):
             boundary_time_nano = boundary_time * 1000000000
             current_time_nano = current_time * 1000000000
 
+            # query the network delays and group them by path ID
             network_delays = {}
             result = self.db_client.query(
                 'SELECT mean(delay) as "Dnet" FROM "E2EMetrics"."autogen".network_delays WHERE time >= {0} and time < {1} GROUP BY path'.format(
@@ -93,6 +94,7 @@ class Aggregator(Thread):
 
                 network_delays[tags['path']] = next(result_points)['Dnet']
 
+            # query the service delays and group them by FQDN, service function instance and endpoint
             service_delays = {}
             result = self.db_client.query(
                 'SELECT mean(response_time) as "Dresponse" FROM "E2EMetrics"."autogen".service_delays WHERE time >= {0} and time < {1} GROUP BY FQDN, sf_instance, endpoint'.format(
@@ -101,15 +103,14 @@ class Aggregator(Thread):
                 metadata, result_points = item
                 # measurement = metadata[0]
                 tags = metadata[1]
+                service_delays[tags['endpoint']] = (next(result_points)['Dresponse'], tags['FQDN'], tags['sf_instance'])
 
-                if tags['endpoint'] not in service_delays:
-                    service_delays[tags['endpoint']] = [(next(result_points)['Dresponse'], tags['FQDN'], tags['sf_instance'])]
-                else:
-                    service_delays[tags['endpoint']].append((next(result_points)['Dresponse'], tags['FQDN'], tags['sf_instnace']))
-
+            # for each path identifier check if there is a media service delay report for the target endpoint - if so, generate an e2e_delay measurement
             for path in network_delays:
+                # check if target endpoint is reported in service delays, that is there is a media service instance running on target endpoint
                 target_endpoint = self.get_target_endpoint(path)
                 if target_endpoint not in service_delays:
+                    # if not continue with the other path IDs
                     continue
 
                 e2e_arguments = {"path_id_f": None, "path_id_r": None, "fqdn": None, "sf_instance": None, "delay_path_f": None, "delay_path_r": None,
@@ -118,21 +119,22 @@ class Aggregator(Thread):
                 e2e_arguments['path_id_f'] = path
                 e2e_arguments['delay_path_f'] = network_delays[path]
 
+                # reverse the path ID to get the network delay for the reversed path
                 reversed_path = self.reverse_path_id(path)
-                assert reversed_path in network_delays
+                assert reversed_path in network_delays  # an assertion is made here, since reversed path should always be reported as well
                 e2e_arguments['path_id_r'] = reversed_path
                 e2e_arguments['delay_path_r'] = network_delays[reversed_path]
 
-                for service_delay in service_delays[target_endpoint]:
-                    response_time, fqdn, sf_instance = service_delay
-                    e2e_arguments['delay_service'] = response_time
-                    e2e_arguments['fqdn'] = fqdn
-                    e2e_arguments['sf_isntnace'] = sf_instance
+                service_delay = service_delays[target_endpoint]
+                response_time, fqdn, sf_instance = service_delay
+                e2e_arguments['delay_service'] = response_time
+                e2e_arguments['fqdn'] = fqdn
+                e2e_arguments['sf_isntnace'] = sf_instance
 
-                    if None not in e2e_arguments.items():
-                        self.db_client.write_points(
-                            lp.generate_e2e_delay_report(e2e_arguments['path_id_f'], e2e_arguments['path_id_r'], e2e_arguments['fqdn'], e2e_arguments['sf_isntnace'],
-                                                         e2e_arguments['delay_path_f'], e2e_arguments['delay_path_r'], e2e_arguments['delay_service'], e2e_arguments['time']))
+                if None not in e2e_arguments.items():
+                    self.db_client.write_points(
+                        lp.generate_e2e_delay_report(e2e_arguments['path_id_f'], e2e_arguments['path_id_r'], e2e_arguments['fqdn'], e2e_arguments['sf_isntnace'],
+                                                     e2e_arguments['delay_path_f'], e2e_arguments['delay_path_r'], e2e_arguments['delay_service'], e2e_arguments['time']))
 
             old_timestamp = current_time
             while current_time != old_timestamp + 5:
diff --git a/docs/aggregation.md b/docs/aggregation.md
index ac19ed207adf9d65bf57eb1084290265e60194d7..cc0e6269df929392b48999688bf9ccb467e4835f 100644
--- a/docs/aggregation.md
+++ b/docs/aggregation.md
@@ -45,6 +45,8 @@ We can easily split the string on **'---'** and, thus, find the source endpoint
 **endpoint2.ms-A.ict-flame.eu**.  
 The delay field value is the network end-to-end delay in milliseconds for the path identified in the tag value.
 
+* A response will traverse the same network path as the request, but in reverse direction.
+
 * Media service measurement - assumption is that we have a measurement for media services' response time, called **service_delays**, providing the following information:
 
 | FQDN (tag) | sf_instance (tag) | endpoint (tag) | response_time | time |