This MIB module manages the Gateway GPRS Support
Node (GGSN) devices. 
        
A GGSN device provides interworking with external 
packet-data network of a particular GPRS service
provider. It provides a combination of IP routing
and GPRS specific functionality to support mobile
users.
        
GTP version1 is introduced in  UMTS release 99 and
Cisco GGSN will support both GTP version 1 (GTP v1)
and version zero (GTP v0) simultaneously. 
        
GTP v1 supports multiple PDP contexts sharing one 
IP address.  TFTs are introduced to achieve this.
Each TFT is associated with a PDP context and there
may exist one PDP context without TFT amongst all 
PDP contexts sharing the same IP address. Each TFT 
has one to eight packet filters each assigned with
a precedence index.  These packet filters are 
evaluated one at a time against the packet header 
information in sequence of their precedence index.
A match is claimed if all the filters are matched
and the PDP context that the TFT belongs to will be
selected, else the checks are performed against the 
filters of another PDP context.  If the packet 
header doesn't contain any TFT packet filter
information, then the PDP context without the TFT is 
selected for further processing.
        
Note on notifications:
        
When an alarm occurs on the device, if the alarm's
severity is higher than the severity filter threshold,
a notification is generated by the device; and if
cGgsnNotifEnabled is 'true', then the device's
SNMP-engine configuration will be searched to
determine where to send the notification. 
        
Acronyms and terms:
        
 APN    Access Point Name
 CSG    Content Service Gateway
 CDR    Charging Data Record
 DCCA   Diameter Credit Control Application
 ETSI   European Telecommunications Standards Institute
 GGSN   Gateway GPRS Support Node
 GPRS   General Packet Radio Service
 GSM    Global System for Mobile communication
 GTP    GPRS Tunneling Protocol
 G-PDU  GTP PDU 
 IE     Information Element
 MS     Mobile Station
 MSISDN Mobile Station ISDN number
 PDP    Packet Data Protocol
 PDU    Protocol Data Unit
 PLMN   Public Land Mobile Network
 SGSN   Serving GPRS support Node
 SLB     Server Load Balancing
 TFT    Traffic Flow Template
 T-PDU  the payload of G-PDU 
 UMTS   Universal Mobile Telecommunications System
 IMS    IP Multimedia Subsystem
 COPS   Common Open Policy Service protocol
 PEP    Policy Enforcement Point
 PDF    Policy Decision Function
 P-CSCF Proxy Call Session Control Function
 PLMN   Public Land Mobile Network
 QS     Quota Server
 UE     User Equipment
        
REFERENCE
        
[1] GSM 03.60: Digital cellular telecommunications
    system (Phase 2+); General Packet Radio Service
    (GPRS); Service description; Stage 2. V7.1.0
        
[2] GSM 09.60: Digital cellular telecommunication
    system (Phase 2+); General Packet Radio Service
    (GPRS); GPRS Tunnelling Protocol (GTP) across
    Gn and Gp Interface. V7.3.0
        
[3] 3GPP; Technical Specification Group Services
    and System Aspects; QoS Concept and Architecture.
    3G TS 23.107 v3.2.0.
        
[4] 3GPP; Technical Specification Group Core Network;
    General Packet Radio Service(GPRS); GPRS 
    Tunnelling Protocol (GTP) across Gn and Gp 
    Interface (Release 1999). 3G TS 29.060 v3.5.0.
        
[5] 3GPP: Technical Specification Group Core Network;
    Policy control over Go interface (Release 5).
    3GPP TS 29.207 V5.2.0