PDN Gateway Overview
▀ Network Deployment(s)
▄ Cisco ASR 5x00 Packet Data Network Gateway Administration Guide
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S2a Interface
This reference point supports the bearer interface by providing signaling and mobility support between a trusted non-
3GPP access point (HSGW) and the PDN Gateway. It is based on Proxy Mobile IP but also supports Client Mobile IPv4
FA mode which allows connectivity to trusted non-3GPP IP access points that do not support PMIP.
Supported protocols
:
Transport Layer: UDP, TCP
Tunneling: GRE IPv6
Network Layer: IPv4, IPv6
Data Link Layer: ARP
Physical Layer: Ethernet
S6b Interface
This reference point, between a P-GW and a 3GPP AAA server/proxy, is used for mobility-related authentication. It
may also be used to retrieve and request parameters related to mobility and to retrieve static QoS profiles for UEs (for
non-3GPP access) in the event that dynamic PCC is not supported.
From Release 12.2 onwards, the S6b interface has been enhanced to pass on the UE assigned IPv6 address (IPv6 prefix
and IPv6 interface ID) to the AAA server. S6b interface also has support for Framed-IPv6-Pool, Framed IP Pool, and
served party IP address AVPs based IP allocation. With this support, based on the Pool name and APN name received
from AAA server, the selection of a particular IP pool from the configuration is made for assigning the IP address.
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