When are hello packets sent? On what different types of media?

EIGRP sends hello packets every 5 seconds on high bandwidth links and every 60 seconds on low bandwidth multipoint links.

-5-second hello:

broadcast media, such as Ethernet, Token Ring, and FDDI

point-to-point serial links, such as PPP or HDLC leased circuits, Frame Relay point-to-point subinterfaces, and ATM point-to-point subinterface

high bandwidth (greater than T1) multipoint circuits, such as ISDN PRI and Frame Relay

-60-second hello:

multipoint circuits T1 bandwidth or slower, such as Frame Relay multipoint interfaces, ATM multipoint interfaces, ATM switched virtual circuits, and ISDN BRIs