Cisco ASR 5000 Series, Обзор продукта

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Mobility Management Entity Overview
▀ How MME Works
▄ Cisco ASR 5000 Series Product Overview
OL-22938-02
How MME Works
This section provides information on the function and procedures of the MME in an EPC network and presents message
flows for different stages of session setup.
The following procedures are supported in this release:
EPS Bearer Context Processing
Purge Procedure
Paging Procedure
Subscriber Session Processing
Connection Setup and Registration Procedures
Subscriber Registration Setup Procedure
UE De-registration Procedures
User-initiated Subscriber De-registration Setup Procedure
Service Request Procedure
User-initiated Service Request Procedure
EPS Bearer Context Processing
EPS Bearer context processing is based on the APN that the subscriber is attempting to access. Templates for all of the
possible APNs that subscribers will be accessing must be configured within the P-GW system.
Each APN template consists of parameters pertaining to how EPS Bearer contexts are processed such as the following:
PDN Type: The system supports IPv4, IPv6, or IPv4v6.
Timeout: Absolute and idle session timeout values specify the amount of time that an MS can remain connected.
Quality of Service: Parameters pertaining to QoS feature support such as for Traffic Policing and traffic class.
A total of 11 EPS bearer contexts are supported per subscriber. These could be all dedicated, or 1 default and 10
dedicated or any combination of default and dedicated context. Note that there must be at least one default EPS bearer
context in order for dedicated context to come up.
Purge Procedure
The purge procedure is employed by the Cisco MME to inform the concerned node that the MME has removed the EPS
bearer contexts of a detached UE. This is usually invoked when the number of records exceeds the maximum capacity
of the system.