Over the years we've been given a number of reasons why smartphone battery life isn't great – whether it's because you've got too many apps running in the background on your phone, or because you have 4G enabled rather than 3G, or perhaps because the location-tracking feature has been enabled on your phone and is sending data about you back to Apple or Google.
But there could also be another reason why your smartphone's battery life is being drained, especially if you're being careful to avoid the reasons above – it could be the internet.
Two engineers working for Google and Cisco have written a research paper for the Internet Engineering Task Force (an international body that develops internet standards) stating that when an IPv6 network is incorrectly configured, it can affect the battery life of a wide range of devices including smartphones, tablets, smartwatches and IoT devices like smart thermostats, smart security systems and smart lighting.
Networks sending out way too many router advertisements
On IPv6 networks, error reporting and diagnostic functions are performed by the Internet Control Message Protocol version 6 (ICMPv6). The protocol also has the router send out periodic messages known as "router advertisements" to all the devices on its network to let them know its IPv6 address.
But when the network isn't configured properly, an overwhelming number of router advertisement messages are sent out, which can drain internet-enabled devices like smartphones because every single time the message is received, the device's CPU has to wake up and process the request.
According to Andrew Youtchenko, a technical leader at Cisco Systems Network Operating Systems Technology Group in Belgium, and Lorenzo Colitti, an IPv6 network engineer with Google in Japan, this is not a big deal for laptops, but for all smaller battery-powered devices, the router advertisements can cause the battery life to drastically decrease.
The researchers said that in some of the networks they monitored, the router was sending out router advertisements at intervals of every three to 10 seconds. And even worse, if you're logged onto a public Wi-Fi network at a shopping mall or airport, even if you're not using your phone at all, the battery life can quickly drain as the mall's Wi-Fi router typically sends out router advertisements to all devices on its network every single time a new user joins or leaves the network.
Admins, please reconfigure your routers
The researchers say that when a smartphone is left on sleep mode, it will consume just 5mA, but when a router advertisement is received, the packet of data received causes the processor to wake up and deal with the packet, causing the smartphone to then use up 200mA for 250 milliseconds.
To prevent this, system administrators are advised to check how many router advertisements they are sending out, and make sure that the router is set to send out only seven router advertisements per hour. Attackers could also use malicious hosts to send out rogue router advertisements, so system administrators should be on a look out for this.
Youtchenko and Colitti also advise that router manufacturers help out by ensuring they offer network administrators the option to reconfigure their routers if the router's router solicitation source address is not the unspecified address, or if the solicitation function contains a valid source link-layer address option.