下面是一道CCNA认证考试试题。problem: routing loops (slow detection of topology change, incorrect routing table/updates) solution: split horizon ('if you learn a route on one interface do not send back that info on that same interface') solution: route poisoning ('set route to infinity') solution: hold-down timers ('ignore updates for some time') problem: counting to infinity (incorrect routing table/updates) solution: define a maximum ('max. hop count +1 = infinity') problem: link-state updates can arrive at different time based on bandwidth (slow and fast links) solution: dampen the periodic update (longer intervals) solution: use time stamps solution: use targeted multicast (not flood), define router （答案 使用targeted ulticast,而不是泛洪……）hierarchies( rtitionnetwork)21) seperate and integrated multiprotocol routing seperate:'ships-in-the-night'routing, protocolisaffectedanyotherprotocolintegrated: replaces native routing algorithm, exchanges common routing info, still maintains seperate routing tables, saves resources, simplifies admin s tasks22) ip classes