Q: airplay in my iphone 5 is not working

Did you turn on AirPlay in your Apple TV? And you do have an Apple TV 2 or 3?

Reset the network settings on your iPhone and log back into the WiFi network that the Apple TV is on.

And you have confirmed that the iPhone and the Apple TV are connected to the same WiFi network and functioning properly on that network. Can you play a song through the ATV with the Music App?

And you might want to try this: http://support.apple.com/kb/TS4215

What model router are you using? Have you checked to see if there are updates available for it, reset it, etc?

This resolved my problem too, but why do you need to set a different ssid for 5ghz and 2.4 ghz. Now the iphone loses the ability to use either frequency.