Question

V-Lans VS Routers

Routers, VLAN, networking requirements, Network performance, Network design

To control network traffic when is it better to use V-Lans and when is it better to use Routers? Is the choice dictated by cost or by networking requirements. If so what are the requirements that would merrit V-Lans over routers?

It depends on what you mean by "control network traffic". There is definitely value and reasons for having both in an environment. It is usually networking requirements that drive you to use one or both in an environment. VLANs should be used to segregate broadcast and multicast domains. Routers can be used for that purpose as well as others such as access control lists, media conversion (e.g. LAN to WAN).