Cisco ASR 5000 Series Administration Manual page 57

Understanding the Service Operation
MME services: MME services are configured to support both mobile-initiated and network-requested EPS bearer
contexts. The MME service must be bound to a logical interface within the same context. Once bound, the interface takes
on the characteristics of an S1-MME interface. Multiple services can be bound to the same logical interface. Therefore, a
single physical port can facilitate multiple S1-MME interfaces.
MME-HSS services: MME-HSS services are configured to support HSS (AAA) functionality with HSS for EPS bearer
contexts. The MME-HSS service must be bound to a logical interface within the same or AAA context. Once bound, the
interface takes on the characteristics of an S6a interface. Multiple services can be bound to the same logical interface.
Therefore, a single physical port can facilitate multiple S6a interfaces.
eGTP services: eGTP services are configured to connect S-GW over S11 interface with MME for EPS bearer contexts.
The eGTP service must be bound to a logical interface within the same or destination context. Once bound, the interface
takes on the characteristics of an S11 interface. Multiple services can be bound to the same logical interface. Therefore, a
single physical port can facilitate multiple S11 interfaces.
Figure given below shows the typical relationship between services, interfaces, and contexts within the system for LTE
networks.
Figure 11. Service, Interface, and Context Relationship Within the System for LTE Networks
The source context used to service a subscriber session is the same as the context in which the MME service is
configured. Each MME service is bound to an IP address in a source context. Once a subscriber has established a EPS
bearer context with a MME, the eNodeB continue to use that same EPS bearer context and MME as the subscriber
moves about the network.
Destination contexts are selected based on the eGTP service configuration in MME for S-GW and P-GW selection.
When the system receives a Create EPS bearer Context Request message from the eNodeB, it examines the available
S-GW and P-GW that can serve APN provided from UE or HSS or Operator Policy in MME.
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Cisco ASR 5000 Series Mobility Management Entity Administration Guide ▄
Terminology ▀
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