Symptom:
Removing Gb loopback from context and NSE status

Conditions:
Following behavior has been reported by customer while doing 2G SGSN testing.

1.	Remove the IP address used as Gb endpoint from the loopback interface level at the context.
2.	Keep all NSVL configured

context sgsn_ingress_2G
    interface Gb_lb loopback
                no ip address 172.20.195.177       <<<<<< remove the IP address
    #exit

  network-service-entity ip-local
    nsvl instance 0 
      nsvl-address ip-address 172.20.195.177 context sgsn_ingress_2G port 5050
    nsvl instance 1 
      nsvl-address ip-address 172.20.195.177 context sgsn_ingress_2G port 5051
    nsvl instance 2 
      nsvl-address ip-address 172.20.195.177 context sgsn_ingress_2G port 5052
    nsvl instance 3 
      nsvl-address ip-address 172.20.195.177 context sgsn_ingress_2G port 5053
  #exit

Customer is expecting the following :
- All NSE Down at network-service-entity ip-config
- All NSE Down at GPRS-service

However, we have not observed any impact on the Gb interface after removing the IP address from the config.