单项选择题 You are the network consultant from Cisco.com. Please point out the reason that STP required when VLANs do not span access layer switches.（）

单项选择题 Acme Nutrition manufactures a wide variety of vitamin supplements. It has a single manufacturing facility with 3 regional warehouses and 16 district sales offices. Currently the manufacturing facility requires 210 IP addresses; each warehouse requires 51 IP addresses; each district sales office requires 11 IP addresses; and the IP WAN requires 38 IP addresses. if Acme Nutrition plans for 20 percent growth in facilities, how many Class C subnets will the district sales offices require?（）

单项选择题 In a VoWLAN deployment, It is recommended（）dBm separation between cells with the same channel.