Multimedia Broadcast and Multicast Service


Multimedia Broadcast and Multicast Service
 
 
This chapter provides information on Multimedia Broadcast and Multicast Service (MBMS) functionality on GGSN. The product Administration Guides provide examples and procedures for configuration of basic services on the system. It is recommended that you select the configuration example that best meets your service model, and configure the required elements for that model, as described in the respective product Administration Guide, before using the procedures in this chapter.
Important: The features described in this chapter are only available if you have purchased and installed MBMS feature support license on your chassis.
This chapter discusses following topics for MBMS support:
 
Introduction
MBMS is an IP datacast type of service in GSM and UMTS cellular network. It eliminates unnecessary replication of data on UMTS wireless networks by transmitting a single stream of data to multiple users. By delivering a single, unidirectional data stream to many subscribers, MBMS makes more efficient use of wireless network resources than traditional point to point connections.
MBMS is a solution for transferring light video and audio clips with a suitable method for mass communications.
MBMS functionality on the system is provided by an existing GGSN service and is enabled by a valid services license.
The main features supported by the Multimedia Broadcast & Multicast Services are:
Important: The ASR 5000 platform supports 225 downlink SGSNs per MBMS Bearer Service through NPU assisted data flow processing. NPU assisted data processing is available on ASR 5000 platforms with release 8.1 or later only.
This service provides two mode of operations:
A broadcast mode is a unidirectional point-to-multipoint service in which data is transmitted from a single source to multiple terminals (UE/MS) in the associated broadcast service area/cell area. The transmitted data can be text to light multimedia services (Audio, Video etc). On the other hand multicast mode is a unidirectional point-to-multipoint service in which data is transmitted from a single source to a pre-defined multicast group of users that are subscribed to the specific multicast service and have joined the multicast group in the associated multicast service area.
The following figure shows the reference architecture of MBMS service in UMTS network.
 
MBMS Reference Architecture in UMTS network
The GGSN provides the following functionality to perform MBMS services:
MBMS is able to use NPU assisted MBMS data flow processing on ASR 5000 platforms so that system can relieve the Session Manager to provide better performance and processing. Currently with NPU assisted data processing, ASR 5000 can support 225 SGSNs per MBMS Bearer Service for downlink of MBMS data.
 
Supported Standards
Support for the following standards and requests for comments (Rafts) have been added with the MBMS functionality:
 
 
Supported Networks and Platforms
This feature supports all ASR 5000 platforms running StarOS Release 8.0 or later with GGSN service for the core network services.
 
Licenses
This feature support requires any one of the following feature licenses installed on the system:
 
 
Services and Application in MBMS
MBMS service can be used as an enabler for various data streaming services. Compared to traditional broadcast services like cell broadcast, MBMS provides multimedia capabilities with relatively high data rates and considerably greater multimedia capabilities.
Some of the applications for MBMS are:
The charging of the MBMS bearer service can be done based on events, content, or flows.
MBMS provides the authentication, key distribution, and data protection for the multicast service users.
 
MBMS References and Entities
Following are the major components and entities required for MBMS service.
 
Gmb Reference
The Gmb reference point handles the broadcast multicast service center (BM-SC) related signaling, which includes the user specific and bearer service messages.
MBMS bearer service specific Gmb signaling includes:
User specific Gmb signaling includes:
 
MBMS UE Context
A MBMS UE context is defined per UE. Session Manager assign a separate context structure for a MBMS UE Context.
Session Manager maintains the following information as part of MBMS UE Context:
Important: For capacity and resource purpose one MBMS UE context is equal to one PDP context.
 
MBMS Bearer Context
The MBMS bearer context is created in the SGSN and GGSN for each provisioned MBMS service. This is created when the first MS requests for this service or when a downstream node requests it. Once created, an MBMS context can be in two states:
 
The MBMS Bearer Context contains all information describing a particular MBMS bearer service and is created in each node involved in the delivery of the MBMS data.
 
Broadcast Multicast Service Center (BM-SC)
The BM-SC includes functions for MBMS user service provisioning and delivery. It serves as an entry point for content provider MBMS transmissions, used to authorize and initiate MBMS Bearer Services within the PLMN. It can also be used to schedule and deliver MBMS transmissions.
The BM-SC consists of five sub-functions:
BM-SC is a functional entity and must exist for each MBMS User Service.
 
How MBMS Works
The Multimedia Broadcast Multicast System provides two types of service provisioning; broadcast and multicast modes. This section describes the procedure of these modes.
 
MBMS Broadcast Mode
The broadcast mode provides unidirectional point-to-multipoint type transmission of multimedia data from a single source to all users that found in a defined broadcast service area. This mode uses radio resources efficiently, since the data is transmitted over a common channel.
MBMS data transmission adapts to the suitable RAN capabilities, depending on the availability of radio resources too. If needed, the bit rate of MBMS data may be varied in order to optimized radio resources.
The following figure shows the basic outline of broadcast mode procedure of an MBMS service in order to broadcast MBMS data within the defined broadcast service area via a packet switched core network.
 
Basic Procedure of MBMS Broadcast Mode
The broadcast service may include one or more successive broadcast sessions. The user can control the enabling or disabling of the MBMS broadcast mode service.
 
MBMS Broadcast Mode Procedure
The MBMS performs following steps for broadcast mode user service:
Step 1
Step 2
Step 3
Step 4
Step 5
 
MBMS Multicast Mode
The multicast mode provides unidirectional point-to-multipoint type transmission of multimedia data from a single content source to a group of subscribers that subscribed to specific multicast service separately. The basic difference between broadcast and multicast modes is that the user does not need to subscribe in each broadcast service separately, whereas in multicast mode the services cab be order separately. The subscription and group joining for the multicast mode service can be done by the operator, user, or a separate service provider.
Like broadcast mode the multicast mode allows the unidirectional point-to-multipoint transmission of multimedia data within the multicast service area. The multicast mode uses radio resources in efficient way by using common radio channel as in broadcast mode. Data is transmitted over the multicast service area as defined by the network operator.
The multicast mode provides the flexibility for the network to selectively transmit to those cells within the multicast service area that contains members of a multicast group.
The following figure shows the basic outline of multicast mode procedure of an MBMS service in order to multicast MBMS data within the defined multicast service area via a packet switched core network.
 
Basic Procedure of MBMS Multicast Mode
A multicast service might consist of a single on-going session or may include several simultaneous multicast sessions over and extended period of time.
Some example of multicast mode service are:
 
MBMS Multicast Mode Procedure
The MBMS performs following steps for multicast mode user service:
Step 1
Step 2
Step 3
Step 4
Step 5
Step 6
Step 7
Step 8
 
MBMS Configuration
This section provides a high-level series of steps and the associated configuration examples for configuring the system with MBMS user service in GGSN services.
To configure the system to perform Multimedia Broadcast and Multicast service:
Step 1
Step 2
Step 3
Step 4
Step 5
Step 6
 
BMSC Profile Configuration
This section provides the configuration example to configure the BM-SC profile in a context:
configure
  context <vpn_context_name> [ -noconfirm ]
     bmsc-profile name <profile_name> [ -noconfirm ]
        default gmb diameter dictionary
        gmb diameter endpoint <endpoint_name>
        gmb diameter peer-select peer < peer_name> [ realm <realm_name> ] [ secondary-peer <sec_peer_name> [ realm <sec_realm_name> ]]
        default gmb user-data mode-preference
        end
 
MBMS GTPP Configuration
This section provides the configuration example to configure the GTPP server parameters in GTPP group configuration mode for MBMS charging:
configure
  context <vpn_context_name> [ -noconfirm ]
     gtpp group default
        gtpp mbms buckets <cc_bucket>
        gtpp mbms interval <duration_sec>
        gtpp mbms tariff time1 <mins> <hours> [ time2 <mins> <hours> ]
        gtpp mbms volume <download_bytes>
        end
 
MBMS APN Configuration
This section provides the configuration example to enable the BM-SC profile for an APN and to configure the MBMS accounting, supported contexts, and timeout parameters in APN configuration mode:
configure
  context <vpn_context_name>
     apn <apn_name> [ -noconfirm ]
        mbms bmsc-profile name <profile_name>
        default max-contexts
        accounting mode gtpp
        default mbms bearer timeout { absolute | idle }
        default mbms ue timeout absolute
        end
 
MBMS Provisioning
This section provides the configuration example for provisioning of MBMS service mode for a GGSN service and associating the MBMS policy for multcast broadcast within the GGSN service in GGSN service configuration mode:
configure
  context <vpn_context_name>
     ggsn-service <ggsn_service_name>
        mbms policy multicast broadcast
        end
 
Save the Configuration
To save changes made to the system configuration for this service, refer Verifying and Saving Your Configuration chapter.
 
Managing Your Configuration
This section explains how to display and review the configurations after saving them in a .cfg file as described in Saving Your Configuration chapter of this guide and also to retrieve errors and warnings within an active configuration for a service.
Important: All commands listed here are under Exec mode. Not all commands are available on all platforms.
Output descriptions for most of the commands are located in Command Line Interface Reference.
show configuration context <vpn_ctxt_name>
 
Gathering MBMS Statistics
The following table lists the commands that can be used to gather the statistics for MBMS.
Important: All commands listed here are under Exec mode. For more information on these commands, refer Executive Mode Commands chapter in Command Line Interface Reference.
Gathering Statistics
show gmb statistics [ apn <apn_name> | bmsc-profile <bmsc_profile_name> ] [ verbose ]
show mbms bearer-service [ mcast-address <mcast_address> ] [ apn <apn_name> ] [ bmsc-profile <bmsc_profile_name> ] [ service-type { multicast | broadcast } ] [ summary | full ] [ all ]
 

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