OpenBSC and MMS

historical

You're on the right path - but there are a couple of things you should be
aware of.

First, for MO (Mobile Orignated) MMS - it's quite straight forward: The
Mobile Device sends an HTTP POST to the MMSC.  However, there is one very
important detail missing: identity management.  In order for the MMSC to
know "who" you are (aka who is posting the MMS Message), it relies on what
has been traditionally known as a "WAP Gateway".  In the WAP2 Context, this
is an HTTP Proxy (WAP1 has its own stack for communication between the
mobile and the WAPGW).  Usually, when you create a PDP Context, the GGSN
will send a RADIUS Accounting message to the WAP Gateway.  This gives the
WAP Gateway you Mobile IP Address and your Phone Number.  When you do the
HTTP POST to the MMSC, the MMSC relies on the WAP Gateway appending your
Phone Number (MSISDN) as an HTTP Request header.  For security reasons, the
MMSC is never directly accessible by the Mobile - only via the WAP Gateway.

So in order to support MO Originated MMS the following need to happen:
1) OpenGGSN needs to send RADIUS
2) An HTTP Proxy that appends the MSISDN as an HTTP Request Header needs to
be had

Second, for MT (Mobile Terminated) MMS - you need everything for MO plus you
need a Push Proxy Gateway.  That is, once an MMS is placed on your MMS it
needs to alert the subscriber that they have an MMS waiting.  This is done
by Posting an MMS Encapsulated MMS Notification to the PPG - with the
subscriber's MSISDN as the recipient.  The PPG will then encapsulate the
message, and send it as one or more specially crafted SMS's (typically via
SMPP).  Once the mobile receives the MMS notification, it'll retrieve the
MMS Content Location from the Notification.  It then sends an HTTP GET via
the WAPGW to the MMS Location (this is a unique url like
http://mmsc.carrier.com/fklvu348f9gervrfd).  The WAPGW will append the
MSISDN as a request header, and the MMSC will validate that the requester
(based on MSISDN in request header) is the owner of the message.  If so, the
response to the HTTP request will be the actual MMS Message.

So in addition to the requirements for MO Originated MMS, MT MMS also
requires:
1) A Push Proxy Gateway

There are opensource PPGs available (See: Kannel).  Where the challenge is,
is that OpenBSC does not have an SMPP Interface today (at least not
osmo-nitb).

I believe there's also an opensource MMSC available today.  Additionally, I
have written my own PPG and MMSC and could assist if you have questions on
these.  The biggest challenge, I think is the SMPP Interface to OpenBSC.
Hacking RADIUS into openggsn, and hacking squid to support radius request
headers (it may already support it?) seem very simple by comparison.

Thanks,
Gus

On Mon, Aug 15, 2011 at 2:33 AM, Simon Barnett <n6vale at googlemail.com>wrote:

> Hi all,
>
> I would like to test sending MMS messages to mobile devices.  Out of
> the box I know OpenBSC supports SMS, which I have been able to use,
> however, I feel that MMS will be more tricky.  My initial thoughts are
> to set up OpenBSC with GPRS using this: -
>
> http://openbsc.osmocom.org/trac/wiki/OpenBSC_GPRS
>
> And then try to bolt some kind of MMS support on top.  Before I get
> started though, I was wondering if anyone had done this before and/or
> had any ideas as to how I might go about implementing this.
>
> I really would appreciate any guidance anyone could offer me.
>
> Thanks in advance,
>
> Simon
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.osmocom.org/pipermail/openbsc/attachments/20110815/44a367bd/attachment.htm>