PDN Gateway Overview
▀ Network Deployment(s)
▄ Cisco ASR 5x00 Packet Data Network Gateway Administration Guide
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The S6b interface on the P-GW or GGSN can be manually disabled to stop all message traffic to the 3GPP AAA during
overload conditions. When the interface is disabled, the system uses locally configured APN-specific parameters
including: Framed-Pool, Framed-IPv6-Pool, Idle-Timeout, Charging-Gateway-Function-Host, Server-Name (P-CSCF
FQDN). This manual method is used when the HSS/3GPP AAA is in overload condition to allow the application to
recover and mitigate the impact to subscribers
Release 12.3 onwards, the IPv6 address reporting through Authorization-Authentication-Request (AAR) towards the
S6b interface is no longer a default feature. It is now configurable through the CLI.
Another enhancement on S6b interface support is the new S6b retry-and-continue functionality that creates an automatic
trigger in the GGSN and P-GW to use the locally configured APN profile upon receipt of any uniquely defined
Diameter error code on the S6b interface for an Authorization-Authentication-Request (AA-R) only. This procedure
would be utilized in cases where a protocol, transient, or permanent error code is returned from the both the primary and
secondary AAA to the GGSN or P-GW. In case of retry-and-continue functionality, P-GW should query from DNS
server if it is configured in APN. S6b failure handling continues the data call. This behavior is only applicable to the
aaa-custom15 Diameter dictionary.
Important:
The S6b interface can be disabled via the CLI in the event of a long-term AAA outage.
Important:
This interface is supported through license-enabled feature. For more information on this support,
refer to the section of this guide.
Supported protocols
:
Transport Layer: TCP, SCTP
Network Layer: IPv4, IPv6
Data Link Layer: ARP
Physical Layer: Ethernet
SGi Interface
This reference point provides connectivity between the P-GW and a packet data network (3GPP TS 23.401). This
interface can provide access to a variety of network types including an external public or private PDN and/or an internal
IMS service provisioning network.
Supported protocols
:
Transport Layer: TCP, UDP
Network Layer: IPv4, IPv6
Data Link Layer: ARP
Physical Layer: Ethernet