* Approaches to merging mobile networks
There are a few approaches to merging mobile networks with each other and with fixed-line Internet connections. An emerging set of dual-mode handsets that support Wi-Fi and cellular connections, for example, will soon ship as voice-over-Wi-Fi enabled, as well as with the inherent ability to roam across the two network types.
Meanwhile, these handset capabilities require some corresponding work at the back end. Some early efforts involve enterprises installing and managing customer premises equipment (CPE) to perform the handoffs. The IT network administrator programs policies into the equipment specifying what network a subscriber should connect to and under what conditions. These efforts are primarily in beta test now.
From the carrier service perspective, Unlicensed Mobile Access (UMA) allows handoff between Wi-Fi (or Bluetooth) networks and cellular networks in at least a couple of commercial mobile phone services today.
Then there is the IP Multimedia Subsystem (IMS) effort, comprising a set of standards blessed by the Third Generation Partnership Project (3GPP) for GSM-based 3G cellular standards and 3GPP2 for CDMA-based 3G cellular standards. IMS is basically about IP-enabling the back end to deliver a consistent end-user experience. In IMS-land, IP becomes the “glue” that lets different networks interoperate and support applications developed by carriers or third parties. As noted last time, MobileIGNITE is the subset of IMS that deals with voice call continuity, or handoff.
“Advance to IMS,” or A-IMS, is an effort spearheaded by Verizon Wireless and announced last month. It brings some enhancements to the emerging set of IMS standards. Perhaps most notably, A-IMS accounts for multimedia application traffic that is not based on the Session Initiation Protocol (SIP). Some say this will better bridge old and new networks, as many support non-SIP applications today. Also, SIP is not a particularly wireless-friendly protocol, due to its chattiness and the comparatively low speeds of wireless networks.
A-IMS is said to also support a scheme for end-to-end security that includes confirming that any devices connecting to the network are compliant with the carrier’s software policy before being granted access and providing for intrusion and malware detection.
* Editor’s Note: Check out Network World’s 7-minute-long WirelessCast podcast, in which Multimedia Editor Jason Meserve discusses the week’s wireless news.
