单项选择题
Which mechanism does External BGP use to prevent the formation of routing loops?（）
A. AS path B. Split horizon C. Poison reverse D. Unicast RPF check
单项选择题 By default, which JUNOS software routing table contains IPv6 unicast routes?（）
单项选择题 What is the purpose of IS-IS level boundaries?（）
单项选择题 Which mechanism accommodates the use of overlapping addresses in 2547bis VPNs?（）
