Wireless Evolution, Software Defined Networks and Network Function Virtualization: Enablers of IoT
Having worked with several Tier 1 wireless carriers closely as customers since 2008, I found John Donovan’s clear explanation of market challenges to be outstanding. As he noted, AT&T and Apple had an exclusive relationship for the iPhone from inception, and the company’s proven history with long-term research has shown their commitment to delivering a solid experience that is generally invisible to the customer. AT&T and its competitors enable many things to happen when it comes to connectivity: the Internet of Things (IoT) cannot become a reality without it.
In the U.S. and Canadian wireless markets, the Personal Communications Services (PCS) 1900 MHz frequency band auctions of the mid-1990’s witnessed what at the time appeared to be a religious war based on technology. The companies that ultimately comprise today’s AT&T were committed to the Global System for Mobile (GSM) standard coming out of Europe, while the firms that became today’s Verizon were generally committed to the Code Division Multiple Access (CDMA) standard originating in the U.S. defense sector. GSM evolved to Generalized Packet Radio Services (GPRS) for low speed data in the second generation (2G), then Universal Mobile Telephone System (UMTS) for third generation (3G), and to Long Term Evolution (LTE) in the fourth generation (4G). Most of the CDMA carriers charted a parallel path with different technology for data services, but eventually ended up on LTE for 4G as well. Fifth generation (5G) platforms, though capable of much higher bandwidth, will go to market using LTE software variants, meaning they will likely function similar to LTE but at a lot higher speed.
The macro level changes above have been visible to subscribers for two reasons: (1) they have resulted in device upgrades to address new capabilities and we, as consumers, have bought the devices; and (2) the carriers have touted the various technology shifts as differentiators vis a vis their competition. Beneath these macro technology shifts, though, other massive technological changes have also been implemented. 2G networks drove the U.S. and Canada into digital networks. With the advent of 3G, carriers shifted away from circuit-switched networks to Internet Protocol (IP) based backbones. More intelligence was pushed to the radio access network (RAN), and connectivity to cell sites migrated from copper to fiber. Core networks migrated from time division multiplexed switches to IP-based switches (Evolved Packet Core), using a hierarchy of open architecture-based systems communicating with digital radio network controllers communicating with cell sites versus the old base station controller to mobile switching center.1,2 Signaling traffic became encapsulated in IP packets. With 4G, intelligence was further pushed to the edge, and the hierarchy of network switches, routers and controllers flattened. AT&T in particular pushed the industry with moving processing power to the top of the tower. Today’s LTE network uses radios equipped with remote electronically tilt-able antennae locally attached to sophisticated computers of their own, in contrast to the original network design of radios connected to remote base station controller supporting hundreds of sites.
With the shift from circuit-switched networks to IP, signaling, control, voice and data traffic effectively are all just packets. With IP networks, carriers have also been able to move to Software Defined Networks, or SDN.3 SDN is about separation of control functions into an abstract, multivendor, open environment, aiming to virtualize data center networks, keeping control separate from network traffic.4 This means that control functions can be centralized into one environment versus using various management platforms and operational support systems (OSS) for vendor-specific products. The other significant change, one that has fully embraced by AT&T in particular, has to been to migrate from vendor proprietary environments supporting network functions to Network Function Virtualization (NFV).5
The first carrier network function that I recall migrating to a virtual instance was the Mobile Management Entity (MME), which is the primary signaling element in EPC and key to LTE (4G). Over the next two to three years, however, we will see Media Gateways (MGWs), switches, routers, load balancers, Mobile Switching Centers (MSCs), and other critical infrastructure components of a carrier network implemented virtually.6 What this means to subscribers is that as the carrier needs to add capacity and functionality, they will be able to do it quickly using virtualized components running on much less expensive and more easily obtained hardware. The carrier will be able to deliver services faster and cheaper, maintaining flat or possibly declining end-user prices. Functionality will be increasing as well as higher bandwidth will enable new applications.
The Tier 1 carriers in the U.S. typically operate networks with over 100,000 cell sites. The broad technology evolution described above has for the most part occurred in the last ten years, essentially since the first generation Apple iPhone. Most importantly, the carriers have implemented these technologies while their networks are in operation. In contrast to highway construction, wireless carriers haven’t taken out portions of their networks for months while they upgrade capabilities, though replacing copper with fiber requires digging ditches and other basic construction activities, for example.
Lastly, as Mr. Donovan noted, all these technology changes have occurred with the carriers spending a lot of capital deploying it, yet subscription fees have not incrementally changed for the most part. To accomplish that, the carriers have to drive down their internal delivery cost, and the myriad firms supplying the technologies to the carriers have to do the same. Subscribers generally have no idea that these shifts are happening. They expect to enjoy the latest technology without knowing the details of what had to happen to bring it to the market. Perfection to an operator truly does mean invisibility.
References
- “The Evolved Packet Core,” Frederic Fermin, Defined in 3GPP Standard R.8, 3GPP.org, 2017.
- “AdvancedTCA,” Advanced Telecommunications Computing Architecture Standard, PICMG.org, 2003.
- “Software-Defined Networking Definition,” Open Networking Foundation, 2017.
- “What SDN is and where it’s going,” Brandon Butler, Network World, 19 Jul 2017.
- “What’s the difference between SDN and NFV,” Brandon Butler, Network World, 10 Jul 2017.
- “NFV Makes Its Move, Telecom and Enterprise NFV Predictions for 2017,” Nati Shalom, Cloudify, 4 Apr 2017.
