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
The access to the external PDN may involve specific functions that include user authentication/authorization, end to end
encryption between MS and Intranet/ISP, allocation of a dynamic address belonging to the PLMN/Intranet/ISP
addressing space, IPv6 address auto-configuration, accounting of user traffic, or connectivity to an external application
server.
The SGi interface is used to support the following functions. The P-GW deduces from the APN the servers to be used
for different functions:
For external IP address allocation if needed (DHCP)
For authentication if required by Protocol Configuration Option (PCO)
For auto-configuration using DHCP
For DNS service
For application functions (E.g. CSCF FQDN, etc)
For IP address auto configuration (IPv6)
S2a (eHRPD)
The Cisco P-GW can anchor non 3GPP calls from a trusted e-HRPD access network using the Proxy Mobile IPv6
protocol. In a PMIPv6 implementation, the P-GW includes the function of a Local Mobility Anchor Point (LMA)
according to draft-ietf-netlmm-proxymip6. Network-based mobility provides mobility for Simple IPv6 capable access
devices without host involvement. This approach to supporting mobility does not require the mobile node to be involved
in the exchange of signalling messages between itself and the LMA. A Mobility Access Gateway (MAG) function on
the HSGW provides the proxy mobility agent and performs the signalling and mobility management with the LMA on
behalf of the attached subscriber device.
Multiple PDN Support
Enables an APN-based user experience that enables separate connections to be allocated for different services including
IMS, Internet, walled garden services, or off-deck content services.
The MAG function on the S-GW can maintain multiple PDN or APN connections for the same user session. The MAG
runs a single node level Proxy Mobile IPv6 tunnel for all user sessions toward the LMA function of the P-GW. When a
user wants to establish multiple PDN connections, the MAG brings up the multiple PDN connections over the same
PMIPv6 session to one or more P-GW LMA's. The P-GW in turn allocates separate IP addresses (Home Network
Prefixes) for each PDN connection and each one can run one or multiple EPC default & dedicated bearers. To request
the various PDN connections, the MAG includes a common MN-ID and separate Home Network Prefixes, APN's and a
Handover Indication Value equal to one in the PMIPv6 Binding Updates.
Congestion Control
The congestion control feature allows you to set policies and thresholds and specify how the system reacts when faced
with a heavy load condition.
Congestion control monitors the system for conditions that could potentially degrade performance when the system is
under heavy load. Typically, these conditions are temporary (for example, high CPU or memory utilization) and are
quickly resolved. However, continuous or large numbers of these conditions within a specific time interval may have an