Last week, I was in the U.K. and I had a bit of a frustrating experience. I have 4G service in the U.S., and I own a 4G-capable smartphone. I know there is 4G service in the U.K., yet I couldn’t get the service working. I tried to manually set up a 4G connection to both O2 and Vodafone but couldn’t make it work, even though it was in the area. Why not? I mean, even if my operator sent me a message and asked for an extra two pounds per day, I might have done it. LTE may be the most advanced network technology ever, but right now, the most straightforward option for me if I want 4G abroad is to buy an unlocked iPhone and use a local prepaid SIM. If that’s not an option, I’m left with good old GSM as my only (more or less guaranteed) mobile roaming service globally.
So, why couldn’t this happen? With LTE technology there are a few factors. Not only do LTE-enabled smartphones need to support a range of different frequencies, but carriers also need to have agreed commercial terms with their roaming partners globally, and then they need to set up and connect their networks. Particularly the latter, from an infrastructure perspective, highlights the whole LTE roaming issue and why there is a Diameter signaling controller (DSC) market in the first place. In order for this roaming to happen, a Diameter routing and interworking function (IWF) product is required. This is not only important to enable scalable Diameter connectivity and interoperability within carriers’ own LTE networks, it is also required to connect individual networks, either directly or through an interconnect hubbing service (called IPX).
Dialogic just launched a product that leads in the simplification of Diameter connectivity and complex legacy interworking within and between LTE and legacy networks. One of the most difficult functions of the DSC function in an LTE network is to cater to interworking. Carriers need to overcome a lot of signaling interworking to make LTE use cases work. What immediately springs to mind is the interworking from Diameter (the LTE protocol) to SS7 (used in the 3G or 2G network) or to RADIUS (used in the WiFi and fixed networks). But I would like to emphasize that there will also be Diameter-to-Diameter interworking issues because vendors may have implemented slightly different specifications. This reminds some of us of the same issue we encountered in the SIP world. So, you can expect an interworking function to hit the market for this use case, as well.
I’m looking forward to getting worldwide 4G service.