Trickle ICE is an optimization of the ICE specification for NAT traversal.

The main bottleneck in ICE is the time it takes to start initiating connectivity checks – it requires collecting all ICE candidates in advance, which in turn means interacting with external servers (STUN and TURN servers). This takes several round trips.

Trickle ICE makes the whole process parallel by having the ability to send single or multiple ICE candidates when they become available without waiting for the collection of all candidates.