Which three are optional extensions of the Frame Relay Local Management Interface specification？（） switched virtual circuit。 virtual circuit status。 simple flow control。 multicasting。 permanent virtual circuit。
Phase I and Phase II DMVPN differ in terms of which of these characteristics？（） Utilization of spoke-to-spoke dynamic tunnels。 Utilization of multipoint GRE tunnels at the hub site。 Utilization of hub-to-spoke dynamic tunnels。 Support for multicast。
发展性评价
充装后的气瓶，应检查（）是否良好。 瓶阀。 与瓶口连接的密封。 拉力。 压力。
Policy-based routing allows network administrators to implement routing policies to allow or deny paths based on all of these factors except which one？（） End system。 Protocol。 Application。 Throughput。
超保护贸易政策的主张是（）
