单项选择题 When designing the WAN module within the enterprise edge, which document is used to specify the connectivity and performance agreements with the service provider?（）

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?（）