PDN Gateway Overview
Features and Functionality - Base Software ▀
Cisco ASR 5x00 Packet Data Network Gateway Administration Guide ▄
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Enhanced Charging
: Name of rulebase to use, which holds the enhanced charging configuration (e.g., eG-CDR
variations, charging rules, prepaid/postpaid options, etc.).
IP
: Method for IP address allocation (e.g., local allocation by P-GW, Mobile IP, DHCP, etc.). IP address ranges,
with or without overlapping ranges across APNs.
Tunneling
: PPP may be tunneled with L2TP. IPv4 may be tunneled with GRE, IP-in-IP or L2TP. Load-
balancing across multiple tunnels. IPv6 is tunneled in IPv4. Additional tunneling techniques, such as, IPsec and
VLAN tagging may be selected by the APN, but are configured in the P-GW independently from the APN.
QoS
: IPv4 header ToS handling. Traffic rate limits for different 3GPP traffic classes. Mapping of R98 QoS
attributes to work around particular handset defections. Dynamic QoS renegotiation (described elsewhere).
After an APN is determined by the P-GW, the subscriber may be authenticated/authorized with an AAA server. The P-
GW allows the AAA server to return VSAs (Vendor Specific Attributes) that override any/all of the APN configuration.
This allows different subscriber tier profiles to be configured in the AAA server, and passed to the P-GW during
subscriber authentication/authorization.
Important:
For more information on APN configuration, refer to the
PDN Gateway Configuration
chapter this
guide.
Assume Positive for Gy-based Quota Tracking
In the current implementation, the PCEF uses a Diameter based Gy interface to interact with the OCS and obtain quota
for each subscriber's data session. Now, the PCEF can retry the OCS after a configured amount of quota has been
utilized or after a configured amount of time. The quota value would be part of the dcca-service configuration, and
would apply to all subscribers using this dcca-service. The temporary quota will be specified in volume (MB) and/or
time (minutes) to allow for enforcement of both quota tracking mechanisms, individually or simultaneously.
When a user consumes the interim total quota or time configured for use during failure handling scenarios, the PCEF
shall retry the OCS server to determine if functionality has been restored. In the event that services have been restored,
quota assignment and tracking will proceed as per standard usage reporting procedures. Data used during the outage will
be reported to the OCS. In the event that the OCS services have not been restored, the PCEF should reallocate with the
configured amount of quota and time assigned to the user. The PCEF should report all accumulated used data back to
OCS when OCS is back online. If multiple retries and interim allocations occur, the PCEF shall report quota used during
all allocation intervals.
When the Gy interface is unavailable, the P-GW shall enter “assume positive” mode. Unique treatment is provided to
each subscriber type. Each functional application shall be assigned unique temporary quota volume amounts and time
periods based on a command-level AVP from the PCRF on the Gx interface. In addition, a configurable option has been
added to disable assume positive functionality for a subscriber group identified by a command-level AVP sent on the
Gx interface by the PCRF.
Bulk Statistics Support
The system's support for bulk statistics allows operators to choose to view not only statistics that are of importance to
them, but also to configure the format in which it is presented. This simplifies the post-processing of statistical data
since it can be formatted to be parsed by external, back-end processors.
When used in conjunction with the Web Element Manager, the data can be parsed, archived, and graphed.
