多项选择题 You have implemented mutual route redistribution between OSPF and EIGRP on a border router. When checking the routing table on one o f the OSPF routers within the OSPF routing domain, you are seeing some, but not all of the expected routes. Which two things should you verify to troubleshoot this problem?（）

单项选择题 You have implemented mutua l route redistribution between OSPF and EIGRP on a border router. When checking the routing table on one of the EIGRP routers within the EIGRP routing domain, you are seeing some, but not all of the expected routes. What should you verify to troubleshoot this problem?（）

单项选择题 What is a key benefit of using a GRE tunnel to provide connectivity bet ween branch offices and headquarters?（）