Cisco ASR 5000 Series, Обзор продукта

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Mobility Management Entity Overview
▀ Features and Functionality - Base Software
▄ Cisco ASR 5000 Series Product Overview
OL-22938-02
Priority to dictate the order in which the servers are used allowing for multiple servers to be configured in a
single context
Routing Algorithm to dictate the method for selecting among configured servers. The specified algorithm
dictates how the system distributes AAA messages across the configured HSS servers for new sessions. Once a
session is established and an HSS server has been selected, all subsequent AAA messages for the session will
be delivered to the same server.
Network Entity Management
This section describes following features:
MME Selection
Packet Data Network Gateway (P-GW) Selection
Serving Gateway (S-GW) Selection
3GPP R8 Identity Support
Tracking Area List Management
Reachability Management
MME Selection
The MME selection function selects an available MME for serving a UE. This feature is needed for MME selection for
handover with minimal MME changes.
MME selection chooses an available MME for serving a UE. Selection is based on network topology, i.e. the selected
MME serves the UE‘s location and in case of overlapping MME service areas, the selection function may prefer MME‘s
with service areas that reduce the probability of changing the MME.
Packet Data Network Gateway (P-GW) Selection
Provides a straightforward method based on a default APN provided during user attachment and authentication to assign
the P-GW address in the VPLMN or HPLMN. The MME also has the capacity to use a DNS transaction to resolve an
APN name provided by a UE to retrieve the PDN GW address.
P-GW selection allocates a P-GW that provides the PDN connectivity for the 3GPP access. The function uses subscriber
information provided by the HSS and possibly additional criteria. For each of the subscribed PDNs, the HSS provides:
an IP address of a PDN GW and an APN, or
an APN and an indication for this APN whether the allocation of a PDN GW from the visited PLMN is allowed
or whether a PDN GW from the home PLMN shall be allocated.
The HSS also indicates the default APN for the UE. To establish connectivity with a PDN when the UE is already
connected to one or more PDNs, the UE provides the requested APN for the PDN GW selection function.