多项选择题
A. multiple Frame Relay PVCs
B. dualWan links to the regional office
C. dualWan links to another branch office
D. single links - one to the regional office and one to another branch office
单项选择题 You are the Cisco Network Designer in Cisco.com. Which of these is a Layer 2 transport architecture that provides packet-based transmission optimized for data based on a dual ring topology?（）
单项选择题 You are the network consultant from Cisco.com. Please point out which Layer 2 access designs does not support VLAN extensions?（）