Cisco ASR 5000 Series, Обзор продукта

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PDN Gateway Overview
Features and Functionality - Base Software ▀
Cisco ASR 5000 Series Product Overview ▄
OL-22938-02
Network Operation Management Functions
This section describes the following features:
Support Interfaces (Reference Points)
Multiple PDN Support
Congestion Control
IP Access Control Lists
Support Interfaces (Reference Points)
S5/S8 GTP (E-UTRAN EPC)
In accordance with 3GPP TS 23.401 the Cisco P-GW platform supports GTPv2-C and GTPv1-U call control and user
plane tunnelling. A GTP tunnel is identified in each node with a Tunnel Endpoint ID (TEID), an IP address and a UDP
port number. The S-GW and P-GW nodes provision separate GTP tunnels for each attached subscriber and for the
individual PDN connections initiated by the UE. The StarOS distributed software architecture enables each function to
run as independent stand-alone services on separate chassis or as simultaneous combination services running on the
same platform.
The S5 reference interface provides user plane tunnelling and tunnel management between an S-GW and P-GW located
within the same administrative domain. It is used for S-GW relocation due to UE mobility and if the S-GW needs to
connect to a non-collocated P-GW for the required PDN connectivity.
The S8 reference interface is an inter-PLMN reference point providing user and control plane between the S-GW in the
V-PLMN and the P-GW in the H-PLMN. It is based on the Gp reference point as defined between SGSN and GGSN.
S8a is the inter PLMN variant of S5.
S6b (E-UTRAN EPC)
The S6b reference interface is run between the P-GW and 3GPP AAA server using Diameter transport and IPv6
addressing. The EPC core network uses the S6b interface to authenticate non-3GPP traffic from e-HRPD access
networks. When the P-GW receives PMIP binding update messages from adjacent HSGW's it initiates an authorization
request to the 3GPP AAA server. It is also possible for the AAA server to initiate reauthorization in cases where the
subscriber profile is modified at the HSS. S2a (PMIPv6) sessions can be terminated based on requests from the HSS
server or HSGW.
SGi
SGi is the reference point between the P-GW and one or more external Packet Data Networks (PDNs). Packet data
network may be an operator external public or private packet data network or an intra operator packet data network, e.g.
for provisioning of IMS services. From the external IP network's point of view, the P-GW is seen as a normal IP router.
The L2 and L1 layers are operator specific.