"This is like deja vu all over again"

Three years ago, when the concept of dual-mode handsets was just getting started, technology battle lines were drawn. There were two camps for providing seamless mobility in dual-mode handsets.

On one side was the ‘pragmatic’ UMA approach: UMA leverages the operators existing network elements and connects to the mobile core as a RAN gateway through standard interfaces.

The other side was a combination of IMS, SIP and VCC.

Constant battles were fought pitting UMA versus IMS (a RAN technology versus a ‘journey’ to an all IP core network); UMA versus SIP (a RAN technology against a session layer signaling protocol); and UMA versus VCC (a 3GPP standard RAN technology for mobile operators against a still-incomplete, almost-standard for fixed operators to connect the SIP core to the GSM mobile core).

In the end, UMA prevailed. It provides full-service transparency, security and scalability with a modest impact on the mobile core. If a mobile operator wants to roll out dual-mode service today, UMA is the only way.

As we enter 2008, a similar battle is shaping up around femtocells. The protocol for connecting the femtocell to the mobile core network has been divided into two camps.

On one side are the more pragmatic “Iu-over-IP” approaches. UMA, the only 3GPP standard Iu-over-IP approach, is leading the charge, but there are vendor specific approaches from Nokia/Siemens, ip.Access and others.

On the other side is some combination of IMS and SIP…again. Some have even erroneously thrown in VCC as a way to connect a femtocell to a mobile core.

As Yogi Berra famously said, “This is like déjà vu all over again!”

Will the SIP/IMS team be successful this time? It may be too early to say, but there are powerful forces behind the push for Iu-over-IP/UMA. Mobile operators do not want to burden the femtocell business case with new SIP/VoIP infrastructure. Many are drawn to the service transparency and relative simplicity of an Iu-over-IP/UMA approach. In the end, UMA is a proven, deployable technology.

2008 will be the year the two approaches duke it out. But if history is any indication, ‘pragmatic’ wins every time.