问题：

[多选] What are three benefits of implementing vlans？（）

A . A more efficient use of bandwidth can be achieved allowing many physical groups to use the same network infrastructure
B . Broadcast storms can be mitigated by decreasing the number of broadcast domains，thus increasing their size
C . A higher level of network security can be reached by separating sensitive data traffic from other network traffic
D . Port-based vlans increase switch-port use efficient，thanks to 802.1Q trunks
E . A more efficient use of bandwidth can be achieved allowing many logical networks to use the same network infrastructure
F . Broadcast storms can be mitigated by increasing the number of broadcast domains，thus reducing theirsize
G . VLANs make it easier for IT staff to configure new logical groups，because the vlans all belong to thesame broadcast domai