实施VoIP局域网是否必须使用VLAN划分？选择题

Your customer does not have VLAN implemented in their network. Is this a problem for a VoIP solution? (1 of 4 answers is correct)

A. No, because a VLAN has no importance in a VoIP solution

B. Possibly, but not necessarily a stopping point if the network is within specifications.

C. No, VLAN is only required when the network topology consists of a single LAN segment.

D. Yes, VoIP solutions require VLAN to be implemented in their network.

VLAN, or virtual LAN, is usually used to seperate the network of one department from the others by vlan tag(mainly by vlan id field) logically, but not physically. It is not a component of VoIP, but it may be used in a VoIP solution.
B is the anwser.