Some wireless access points and routers allow users to choose between AES or TKIP security. You should always choose AES which stands for "Advanced Encryption Standard" and is without question the best choice for securing your wireless communication.
AES encryption was introduced with the WPA2 protocol. The older TKIP or "Temporal Key Integrity Protocol" was a temporary solution used right after WEP was being tossed out. It was never intended to be a permanent solution, it was just what they pulled together as a patch at the time.
All you really need to remember is to choose AES security when setting up your wireless network.