What is split routing

Split routing refers to allowing traffic to specific networks and IP addresses only through a VPN tunnel. All other internet traffic will be routed via your internet service provider (ISP). This is important in business use cases. 

For instance, if an employee is connected to the office network via VPN from a remote location. With split routing enabled, traffic destined for specifc tragets will be passing through the VPN, like accessing webservers, database servers, payroll system etc. If he is browsing other external websites while connected to the VPN, then those traffic will be transmitted through his ISP.