单项选择题
Routers A and B are connected with a point-to-point OC-3 interface. Each router’s OC-3 interface is configured for both Level 1 and Level 2. The routers are configured in different areas.How many IS-IS adjacencies exist between the two routers？（）
A.0 B.1 C.2 D.3
单项选择题 InIS-IS，howdoestherestartingrouterinformitshelpersthatarestartseventoccurred？（）
单项选择题 YouhaveaLevel1-onlyrouter（RouterA）inIS-ISarea49.0001.HowdoesRouterAlearnhowtogettoIPprefixedinotherareas？（）
多项选择题 WhichtwoarevalidIS-ISPDUtypes？（）
