Model Routing

Control Expert Routing in Mixture-of-Experts Models

A mixture-of-experts layer can contain far more parameters than it evaluates for each token. A router scores a set of experts, selects a small subset, and sends each token only to those selected computation paths. The parameter count can grow without making every token execute every expert. That sparse structure creates a separate systems problem: the router decides where computation lands. Two models with the same experts and the same nominal top-k routing can have very different behavior if one spreads tokens across experts and the other concentrates them on a few paths.