Wiktionary
core switch
n. (context computing, networking English) A high-capacity switch usually at the core or backbone of a computer network, aggregating network traffic to the Internet or a WAN.http://www.techopedia.com/definition/28787/core-switch-networking
Usage examples of "core switch".
In abrupt fury, Bickel pulled the master override stop from his core switch, jammed a set of jumper jacks across the AAT controls, opened the core system for standard reference comparison.