MMS FAQ

From CDGWiki

Taskforce Status: No longer active

Contents 1 MMS Non-roaming FAQ 1.1 Is a normal packet data session established when sending or receiving MMS messages? 1.2 How are MMS messages billed to the customer? 1.3 What is Bill-and-Keep? 1.4 If there is no wholesale billing when MMS messages are sent from one carrier network to another, how does each carrier collect revenue? 1.5 If a message is sent between CDMA and GSM networks, where does transcoding occur? 1.6 Does MMS require additional security measures? 1.7 Which standards govern MMS? Are they the same for both CDMA & GSM? 2 MMS Roaming FAQ 2.1 Does a mobile access their home MMSC even when they are roaming in a visited network? 2.2 Since partners don’t wholesale bill each other for MMS service using the Bill-and-Keep approach, how does a visited network collect revenue? 2.3 Are there any issues with a user being able to access their home MMSC while roaming? 2.4 Is there any special provisioning required for an MMS capable handset to support MMS roaming?

[edit] MMS Non-roaming FAQ

[edit] Is a normal packet data session established when sending or receiving MMS messages?

Yes, a packet data session is established to allow the user to access their home MMSC. It is helpful to view the MMSC simply as an application server. In order to access an application server, a mobile must establish a data session. Note that the data session is always initiated by the mobile. As such, MMS message delivery begins with an MMS notification message sent to the mobile via SMS. Once notified, the mobile initiates a data session and uses WAP, IMAP, or SIP to retrieve the message over the MM1 interface. From the radio network perspective, the data session for MMS transport is no different than any other data session since WAP, IMAP, and SIP signaling and transport all occur above the IP layer.

[edit] How are MMS messages billed to the customer?

Retail billing of the MMS service itself is always between the home carrier and the user. The method of retail billing for MMS is determined entirely by the carrier.

[edit] What is Bill-and-Keep?

Bill-and-keep is the recommended billing approach for MMS traffic that involves multiple carriers. Using this approach, carriers retail bill their own customers for MMS messaging and keep the revenue but do not wholesale bill partners for the MMS service itself. Since MMS message origination and delivery is always between the user and their home MMSC, even in roaming scenarios, the MMSC server and message storage resources used are always those of the user’s home network. Note that in the case of roaming, wholesale billing may still occur for the underlying packet data bandwidth that is used to transport these messages in a visited network.

[edit] If there is no wholesale billing when MMS messages are sent from one carrier network to another, how does each carrier collect revenue?

Whether originating or receiving an MMS message, the user is always served by their home MMSC. Therefore, when a message is sent from one carrier network to another in a non-roaming scenario, this implies that the originator is a customer of the originating network and the recipient is a customer of the destination network. The originating carrier may retail bill their customer for originating the MMS message and the destination carrier may retail bill their customer for delivery of the MMS message. However, no wholesale billing occurs between the originating and destination carriers.

Open Question: In the case of GSM, only the originator pays. So, for CDMA-to-GSM inter-carrier MMS, how would recipient GSM operator collect for network usage to delivery the MMS to the recipient?

[edit] If a message is sent between CDMA and GSM networks, where does transcoding occur?

Because CDMA and GSM carriers may use different codecs (e.g. CDMA QCELP vs. GSM AMR speech codecs), MMS message content may need to be adapted to the appropriate format before delivery to a recipient user in a different network. This adaptation from one codec to another is known as transcoding and may be implemented as follows:

1. Generally speaking, the recipient MMSC is responsible for content adaptation to an appropriate format for the recipient user device. As such, MMSC servers in both CDMA and GSM networks should have the capability to transcoding between common codecs used in both networks and should perform this transcoding when necessary
2. Alternatively, carriers may have agreements established between one another that require MMS messages to adhere to specifically defined formats. In such cases, transcoding may be performed either by the originating MMSC or by an MMS hub through which messages are routed

[edit] Does MMS require additional security measures?

No, because MMS relies upon establishment of a data session to transport MMS messages, the originating and terminating mobiles will be subjected to standard authentication procedures when the data session is established. In addition, it is recommended that MMS messages transported between carriers utilize a secure CRX network that is not accessible from the Internet.

[edit] Which standards govern MMS? Are they the same for both CDMA & GSM?

A list of links to MMS inter-carrier/inter-working standards and/or guidelines may be found at MMS_CAT_Documents.

[edit] MMS Roaming FAQ

[edit] Does a mobile access their home MMSC even when they are roaming in a visited network?

Yes, the user always accesses their home MMSC regardless of whether they are in their home network or roaming in a visited network. If the user is roaming in a visited network, a packet data roaming session is established to allow the mobile to access its home MMSC. This session is the same as any other packet data roaming session that would be established in order for a roamer to access an application server in their home network.

[edit] Since partners don’t wholesale bill each other for MMS service using the Bill-and-Keep approach, how does a visited network collect revenue?

While there is no wholesale billing for the MMS service itself, wholesale billing may still occur for the underlying data bandwidth used to transport MMS in a visited network. When roamers send or receive MMS messages in a visited network, data bandwidth and radio resources in that network are used to facilitate MMS messaging between the user and their home MMSC. From the visited network perspective, this is simply a data session between the roaming user and a server in their home network (in this case, the server happens to be the user’s home MMSC). Therefore, as with any other packet data session for an inbound roamer, the visited network will wholesale bill the home network for bandwidth used during the session.

[edit] Are there any issues with a user being able to access their home MMSC while roaming?

Being able to access the home MMSC while roaming is no different than being able to access an application server in the home network while roaming. When using L2TP or Mobile IP roaming architectures that logically place the roamer in the home network, there should be no issue with accessing the home MMSC. When using Simple IP, the home and visited networks must coordinate to ensure that the IP address of the home MMSC MM4 interface is visible and accessible from the visited network.

[edit] Is there any special provisioning required for an MMS capable handset to support MMS roaming?

No MMS-specific provisioning is required. However, MMS roaming does require the handset to support packet data roaming which implies appropriate provisioning of PRL information and authentication keys necessary for the handset to acquire service in the visited network.

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