5 Service Provider Discovery

26.2373GPPIP Multimedia Subsystem (IMS) based Packet Switch Streaming (PSS) and Multimedia Broadcast/Multicast Service (MBMS) User ServiceProtocolsRelease 17TS

5.1 Introduction

In order for the UE to access the PSS and MBMS User Service using IMS, it shall implement an IMS client that registers to the IM CN Subsystem [7]. This assumes that the UE has attached to a network and established PS connectivity through a PDP context according to 3GPP TS 23.060 [16] and has successfully completed the P-CSCF discovery procedure [7]. Once the UE is registered to the IM CN Subsystem, it can proceed to the Discovery of the PSS and MBMS User Service.

This clause specifies how the UE performs the PSS and MBMS Service Provider Discovery. This is equivalent to discovering the list of IMS PSI of the SDF and relative Service Providers. There are several means for the UE to acquire this information. The UE shall implement the DNS based Service Provider Discovery as defined in clause 5.2. Other methods are optional.

5.2 DNS

In this case, the SDFs are discovered using the DNS SRV mechanism in accordance with RFC 2782 [17], with the following input parameters:

– Service: Defined as "pss-mbms-user-service".

NOTE: to be registered with IANA.

– Protocol: Can take values "http" or "sip". Specifies the protocol to contain the particular service.

– Domain name: the domain for which the returned records are valid. The value can be derived from the ISIM. Without ISIM it can be derived from USIM together with MCC (Mobile Country Code) and MNC (Mobile Network Code) according to TS 23.003 [29]. If not possible, the domain name can be derived from network attachment phase (DHCP server). Manual configuration overrides these possibilities.

Figure 5: Service Provider Discovery with DNS

The output of the DNS SRV lookup is an ordered list of domain name, each pointing to a SDF server available within the specified Domain name.

5.3 Others

Alternatively, the SDF PSI may also be signalled to the UE by the following means:

– Manually provisioned in the UE.

– OMA Device Management.

– SMS.

– OMA Push.

– MBMS.

– DHCP.