John McCool, the sales chief for Cisco's (CSCO) Global Enterprise unit (though he was officially called the unit's CTO), is leaving the company. His position will be assumed by wireless sales VP Tom Wilburn. A 17-year-vet, McCool played a key role in the growth of Cisco's dominant Ethernet switching business. He was moved over to a sales role in 2011. Paul Mountford, another top enterprise sales exec, left last August.