Update config Section

1. QoS config update
2. UPF configuration update
3. UE address allocation notes cleanup

Change-Id: Ibdeb0f54a25fd39da094b03ad2f762812592c0e7
diff --git a/configuration/config_rest.rst b/configuration/config_rest.rst
index 8ce5ea5..e256660 100644
--- a/configuration/config_rest.rst
+++ b/configuration/config_rest.rst
@@ -91,6 +91,12 @@
     REST API can use PUT Method to modify/replace the device group configuration.
     IMSIs can be added, removed through PUT Method.
 
+.. note::
+   If UPF is used to allocate UE address allocation then even if you have specified UE
+   address pool in the slice config, you still need to add the address pool
+   configuration in the UPF deployment.
+
+
 Network Slice Configuration
 """""""""""""""""""""""""""
 Below example creates Network Slice with set of eNBs, UPF and device groups.