We can set up the means by which to segregate (VLAN) and route traffic within your local area network (LAN) and from outside your network (WAN). For example, it is popular to separate VoIP traffic from every day data traffic for Quality of Service (QoS) purposes. This also makes it possible to manage different types of traffic individually rather than taking down the whole network if and when something needs to be maintained. Routing also allows one to send traffic for VoIP out one WAN connection while sending data out a completely different WAN or over MPLS to a single phone system or call center.