PDN Gateway Overview
Features and Functionality - Base Software ▀
Cisco ASR 5x00 Packet Data Network Gateway Administration Guide ▄
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In addition, the P-GW allows configuration of diameter packets with DSCP values.
GTP-U on per APN Basis
This feature provides the flexibility to have a different DSCP marking table on per APN basis so that traffic on each of
the APNs can be marked differently, depending on the needs of the APN.
The S-GW/P-GW supports configurable DSCP marking of the outer header of a GTP-U tunnel packet based on a
QCI/THP table for the S5/S8 and Gn/Gp interfaces. This feature allows configuring DSCP marking table on a per APN
basis.
Previously, DSCP marking table was configured on P-GW service level. As part of this requirement, CLI was added to
associate the qos-qci-mapping table in APN.
In order to be backward compatible with older configurations, if a DSCP marking table is associated with P-GW service
and not with the APN, then the one in P-GW service will be used. If table is associated in both P-GW service and APN,
then the one on APN will take precedence.
Dynamic GTP Echo Timer
The Dynamic GTP Echo Timer enables the eGTP and GTP-U services to better manage GTP paths during network
congestion. As opposed to the default echo timer, which uses fixed intervals and retransmission timers, the dynamic
echo timer adds a calculated round trip timer (RTT) that is generated once a full request/response procedure has
completed. A multiplier can be added to the calculation for additional support during congestion periods.
Important:
For more information, refer to the
Configuring the GTP Echo Timer
section located in the
Configuring Optional Features on the P-GW
section of the
PDN Gateway Configuration
chapter.
Dynamic Policy Charging Control (Gx Reference Interface)
Dynamic policy and charging control provides a primary building block toward the realization of IMS multimedia
applications. In contrast to statically provisioned architectures, the dynamic policy framework provides a centralized
service control layer with global awareness of all access-side network elements. The centralized policy decision
elements simplify the process of provisioning global policies to multiple access gateways. Dynamic policy is especially
useful in an Always-On deployment model as the usage paradigm transitions from a short lived to a lengthier online
session in which the volume of data consumed can be extensive. Under these conditions dynamic policy management
enables dynamic just in-time resource allocation to more efficiently protect the capacity and resources of the network.
Dynamic Policy Control represents the ability to dynamically authorize and control services and application flows
between a Policy Charging Enforcement Function (PCEF) on the P-GW and the PCRF. Policy control enables a
centralized and decoupled service control architecture to regulate the way in which services are provisioned and
allocated at the bearer resource layer.
The StarOS 9.0 release included enhancements to conform with 3GPP TS 29.212 and 29.230 functions. The Gx
reference interface uses Diameter transport and IPv6 addressing. The subscriber is identified to the PCRF at session
establishment using IMSI based NAIs within the Subscription-ID AVP. Additionally the IMEI within the Equipment-
Info AVP is used to identify the subscriber access terminal to the policy server. The Gx reference interface supports the
following capabilities:
Authorize the bearer establishment for a packet flow
