▀ How the PDN Gateway Works 
▄ Cisco ASR 5000 Series Product Overview 
The UE acknowledges the receipt of the request with a VSNCP-Term-Ack (PDNID=x). 
The HSGW optionally sends a Router Advertisement (RA) with assigned HNP and prefix lifetime=0. 
 
 
GTP PDN Gateway Call/Session Procedures in an LTE-SAE Network 
The following topics and procedure flows are included: 
 
  Subscriber-initiated Attach (initial) 
  Subscriber-initiated Detach 
 
Subscriber-initiated Attach (initial) 
This section describes the procedure of an initial attach to the EPC network by a subscriber.