iPad WiFi problem due to poor DHCP management?
Intermittent WiFi problems have been the thorn in many iPad owners’ sides since the tablet first began shipping, but so far Apple haven’t been able to address the issue. Now Princeton University’s IT department has stepped in with a possible explanation, and according to them it’s not the iPad hardware that’s at fault but iPhone OS 3.2 that it runs.
Princeton’s network engineers have found that the connectivity issue arrises when the iPad fails to renew its DHCP lease – a process which would renew its IP address with the router it is connected to – but continues to attempt to use the same IP. In the meantime, the router may block what it perceives as a lapsed IP, or it may have assigned that address to another wireless client. However, in certain circumstances, the iPad fails to refresh its DHCP even when a full connection isn’t being made, leaving the user unable to get online.
“So to summarize, we can reproduce the problem by allowing the iPad to lock its screen before DHCP lease renewal time, and then allowing it remain in that state (powered on with its screen locked) until the DHCP lease has expired, assuming the iPad experiences no 802.11 wireless disconnect/reconnect events during that time.” Princeton University
Workarounds currently include performing a full power cycle (i.e. not just locking the iPad but fully shutting it down and rebooting it) and turning the wireless off and then on again in the tablet’s settings. Moving outside the WiFi router’s range and then back into it again has also been shown to help on some occasions. Princeton say they’re working with Apple on further investigating the problem, and the IT department hope it can be addressed with a software patch for iPhone OS 3.2.