(
Private
Network-to-
Network
Interface) A routing protocol used between ATM switches in an ATM network. It lets the switches inform each other about network topology so they can make appropriate forwarding decisions. PNNI is based on the OSPF protocol, but also measures line capacities and delays rather than just simple cost metrics. Thus, ATM switches can dynamically reroute packets based on current line conditions. See
I-PNNI.