Gn/Gp Handoff Support - Cisco ASR 5x00 Administration Manual

PDN Gateway Overview
optionally share or mirror a single quota database so as to support Gy session failover from one server to the other. For a
more scalable installation, a layer of proxies or other Diameter agents can be introduced to provide features such as
multi-path message routing or message and session redirection features.
The Cisco implementation is based on the following standards:
 RFC 4006 generic DCCA, including:
 CCR Initial, Update, and Final signaling
 ASR and RAR asynchronous DCCA server messages
 Time, Total-Octets, and Service-Specific-Units quota management
 Multiple independent quotas using Multiple-Services-Credit-Control
 Rating-Group for quota-to-traffic association
 CC-Failure-Handling and CC-Session-Failover features
 Final-Unit-Action TERMINATE behavior
 Tariff-Time-Change feature.
 3GPP TS 32.299 online mode "Gy" DCCA, including:
 Final-Unit-Action REDIRECT behavior
 Quota-Holding-Time: This defines a user traffic idle time, on a per category basis, after which the usage
 Quota-Thresholds: These AVPs define a low value watermark at which new quota will be sought before
 Trigger-Type: This AVP defines a set of events which will induce a re-authentication of the current

Gn/Gp Handoff Support

In LTE deployments, smooth handover support is required between 3G/2G and LTE networks, and Evolved Packet
Core (EPC) is designed to be a common packet core for different access technologies. P-GW supports handovers as user
equipment (UE) moves across different access technologies.
Cisco's P-GW supports inter-technology mobility handover between 4G and 3G/2G access. Interworking is supported
between the 4G and 2G/3G SGSNs, which provide only Gn and Gp interfaces but no S3, S4 or S5/S8 interfaces. These
Gn/Gp SGSNs provide no functionality introduced specifically for the evolved packet system (EPS) or for
interoperation with the E-UTRAN. These handovers are supported only with a GTP-based S5/S8 and P-GW supports
handoffs between GTPv2 based S5/S8 and GTPv1 based Gn/Gp tunneled connections. In this scenario, the P-GW works
as an IP anchor for the EPC.
Important:
services must be co-located on the same node and configured within the same context for optimum interoperation.
Important:
Supported Logical Network Interfaces (Reference Points) section in this chapter.
is returned and no new quota is explicitly requested
the quota is entirely gone; the intent is to limit interruption of user traffic.
These AVPs exist for all quota flavors, for example "Time-Quota-Threshold".
session and its quota categories.
To support the seamless handover of a session between GGSN and P-GW, the two independent
For more information on Gn/GP handoffs, refer to Gn/Gp GGSN/SGSN (GERAN/UTRAN) in the
Cisco ASR 5x00 Packet Data Network Gateway Administration Guide ▄
Features and Functionality - Base Software ▀
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