Cisco Cisco Mobility Unified Reporting and Analytics System Guida Utente
Mobility Management Entity Overview
▀ Features and Functionality - Base Software
▄ Cisco ASR 5000 Series Product Overview
658
OL-24419-05
SCTP Multi-homing for S6a
The Cisco MME service supports up to four SCTP bind end point IPv4 or IPv6 addresses for the S6a interface.
SCTP Multi-homing for S1-MME
The Cisco MME service supports up to two SCTP bind end point IPv4 or IPv6 addresses for the S1 -MME interface.
Serving Gateway Pooling Support
The S-GW supports independent service areas from MME pooling areas. Each cell is associated to a pool of MMEs and
a pool of Serving Gateways. Once a cell selects an MME, that MME is able to select an S-GW which is in an S-GW
pool supported by the cell.
Static S-GW pools can be configurable on the MME. Each pool is organized as a set of S-GWs and the Tracking Area
Identities (TAIs) supported by them, known as a service area (SA). The incoming TAI is used to select an SA. Then,
based on protocol and statistical weight factors, an S-GW is selected from the pool serving that SA. The same list of S-
GWs may serve multiple TAIs. Static S-GW pools are used if there is no DNS configured or as a fallback if DNS
discovery fails.
a pool of Serving Gateways. Once a cell selects an MME, that MME is able to select an S-GW which is in an S-GW
pool supported by the cell.
Static S-GW pools can be configurable on the MME. Each pool is organized as a set of S-GWs and the Tracking Area
Identities (TAIs) supported by them, known as a service area (SA). The incoming TAI is used to select an SA. Then,
based on protocol and statistical weight factors, an S-GW is selected from the pool serving that SA. The same list of S-
GWs may serve multiple TAIs. Static S-GW pools are used if there is no DNS configured or as a fallback if DNS
discovery fails.
For additional Information on TAI lists, refer to the
section in this overview.
Serving Gateway Selection
The Serving Gateway (S-GW) selection function selects an available S-GW to serve a UE. This feature reduces the
probability of changing the S-GW and a load balancing between S-GWs. The MME uses DNS procedures for S-GW
selection.
probability of changing the S-GW and a load balancing between S-GWs. The MME uses DNS procedures for S-GW
selection.
The selection is based on network topology; the selected S-GW serves the UE’s location, and in the case of overlapping
S-GW service areas, the selection may prefer S-GWs with service areas that reduce the probability of changing the S-
GW. If a subscriber of a GTP-only network roams into a PMIP network, the PDN GWs (P-GWs) selected for local
breakout supports the PMIP protocol, while P-GWs for home routed traffic use GTP. This means the S-GW selected for
such subscribers may need to support both GTP and PMIP, so that it is possible to set up both local breakout and home
routed sessions for these subscribers.
S-GW service areas, the selection may prefer S-GWs with service areas that reduce the probability of changing the S-
GW. If a subscriber of a GTP-only network roams into a PMIP network, the PDN GWs (P-GWs) selected for local
breakout supports the PMIP protocol, while P-GWs for home routed traffic use GTP. This means the S-GW selected for
such subscribers may need to support both GTP and PMIP, so that it is possible to set up both local breakout and home
routed sessions for these subscribers.
Session and Quality of Service Management
This support provides a foundation for contributing towards improved Quality of User Experience (QoE) by enabling
deterministic end-to-end forwarding and scheduling treatments for different services or classes of applications pursuant
to their requirements for committed bandwidth resources, jitter and delay. In this way, each application receives the
service treatment that users expect.
deterministic end-to-end forwarding and scheduling treatments for different services or classes of applications pursuant
to their requirements for committed bandwidth resources, jitter and delay. In this way, each application receives the
service treatment that users expect.
The MME Operator Policy configuration allows the specification of QoS for each traffic class that can either be used as
a default or as an over ride to the HSS settings.
In LTE-EPC 4G architectures, QoS management is network controlled via dynamic policy interactions between the
PCRF and PDN GW. EPS bearer management is used to establish, modify or remove dedicated EPC bearers in order to
provide service treatments tied to the needs of specific applications/service data flows. The service priority is
provisioned based on QoS Class Identifiers (QCI) in the Gx policy signaling. PCRF signaling interaction may also be
used to establish or modify the APN-AMBR attribute assigned to the default EPS bearer.
a default or as an over ride to the HSS settings.
In LTE-EPC 4G architectures, QoS management is network controlled via dynamic policy interactions between the
PCRF and PDN GW. EPS bearer management is used to establish, modify or remove dedicated EPC bearers in order to
provide service treatments tied to the needs of specific applications/service data flows. The service priority is
provisioned based on QoS Class Identifiers (QCI) in the Gx policy signaling. PCRF signaling interaction may also be
used to establish or modify the APN-AMBR attribute assigned to the default EPS bearer.