单项选择题
What is the purpose of IS-IS level boundaries?（）
A. Restrain the formation of adjacencies. B. Control the flooding scope of link-state PDUs. C. Partition the L2 backbone into multiple domains. D. Aggregate L1 domains into a contiguous backbone.
单项选择题 Which mechanism accommodates the use of overlapping addresses in 2547bis VPNs?（）
多项选择题 In which two ways can the router ID selection be controlled?（）
单项选择题 Why does IS-IS use the SPF algorithm?（）
