Looking at...


The signalling storm A


s smartphone sales surge and become more enmeshed in daily life, the


dynamics of mobile communica- tions are clearly changing. People are now spending more time using non-voice applications such as games, email, text messaging and social media. While many of these applica-


tions can be downloaded for free, they come with a hefty price tag: they siphon device power and drain battery life. Meanwhile, the sheer number of times these ap- plications contact the network as a background task is creating major problems for operators, increasing signalling loads significantly and causing network outages. Te ramifications of shorter


battery life and network downtime could result in more customer complaints, not only for device manufacturers but for mobile op- erators. Customer experience is key, and to ensure a good experience for their users, mobile operators must be able to handle signalling surges seamlessly or risk losing to competitors. Fortunately, there are now service


assurance solutions with integrated network analytics that provide mo- bile operators with the insight they need to minimize the impact on the overall mobile experience. Today’s smartphones interact


with the mobile network in a significantly different way from the mobile device for which it was originally optimized – laptops. Networks then were designed to keep the data connection open for long periods to reduce the delay in transferring data between client and servers. Tis enabled networks to respond quickly but led to higher power consumption in the user equipment (UE). With their smaller battery


capacity, smartphones were highly 34 UMTS SGSN CSCF HSS IMS SERVICES AS MGW PCRF MME PGW LTE ACCESS


System Architecture Evolution SGW


Evolved Packet Core Eye of the signalling storm: the network core elements under pressure as data traffic increases


affected by this communication method. To extend battery life, device manufacturers devised and implemented a new methodology, Proprietary Fast Dormancy, where the device itself tells the network to move into an idle state when no data connection is needed. Although this method improves battery life, it increases the number of times the device must ‘talk’ to the network.


The application factor More than 500000 applications are available for users to download for the iPhone alone. Depending on their requirements, these apps can cause severe pressures and outages. For example, social media and email applications are constantly seeking a network connection to check for updates. Apps that require constant


network communication can gener- ate such heavy traffic loads that networks can grind to a halt. Sophisticated users are not just


adding new apps; they modify handsets, add or remove functional- ity and re-flash the operating system to personalize and improve their phones. Tis can cause a myriad of additional issues.


Tese issues present an ongoing


problem for networks, despite the best efforts of device manufactur- ers, app developers and operators. Service assurance solutions can help operators pinpoint problems and provide information to solve problems. To pinpoint the users and loca-


tions where these problems are oc- curring, service assurance solutions must identify: • the amount of signalling traffic generated in normal operations – the number of times the device moves from active to idle, as well as the average time Packet Data Protocol (PDP) context is active. Tese average numbers will indicate where issues may lie.


• the amount and type of user traf- fic generated by each UE. Many applications, such as instant messaging, Skype and email, are very ‘chatty’, with keep-alives that increase the amount of signalling. To gain visibility into these


issues, operators must be able to analyse customer behaviours and underlying network performance, by application, in real-time. Tis level of granularity enables operators to rapidly identify users,


locations, apps and devices that are adversely impacting the network – and the customer experience. With this intelligence, mobile


operators can begin to determine the scale and potential impact of the problem – such as whether there is a single device type, ap- plication or location that is causing the biggest strain. Tis type of actionable information enables operators, device manufactures and app developers to work together to proactively enhance the mobile experience.


Managing the storm Smartphone users are generating unforeseen effects on network operations by constantly download- ing applications and modifying their devices – a trend that will only continue as consumers become more sophisticated. Te problem is not going to go


away, but it can be managed. With a greater understanding of the prob- lem, operators can take corrective actions to minimize the impact on network capacity and performance. Without it, operators will be at the mercy of changing conditions and their networks may sustain damage in the signalling storm.


LAND mobile September 2012


As smartphones add to the data load to be shouldered by mobile operators, Neil McKinlay of the network testing company Empirix, looks into what’s happening


PSTN


PACKET DATA NETWORK


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