An anonymous reader writes: Two engineers from Cisco and Google have raised the problem of IPv6 networks that drain smartphone battery life and issued a series of tips for other network admins on why and how to properly configure their networks. The problem is because of Router Advertisements (RAs). These are periodic messages sent by the router to all network clients telling them its IPv6 address, at which it can be reached. Apparently some networks are sending these as often as every 3 seconds, while the engineers say the proper interval should be 7 per hour. Hence the reason why your battery life is often drained even if your phone is in sleep mode, but connected to a local network.