【答案】:A 6、在 OSI 环境中,不同开放系统对等实体之间的通信,需要(N)实体向相邻的上一层(N+1)实体提供一种能力,这种能力称为( )。 A.(N)协议 B.(N)服务 C.(N)用户 D.(N)功能 【答案】:B 7、BGP runs over a reliable transport (请作答此空). This eliminates the need to implement explicit update fragmentation, retransmission, acknowledgement, and ( ). Any authentication scheme used by the transport protocol may be used in addition to BGP's own ( )mechanisms. The error notification mechanism used in BGP ( )that the transport protocol supports a “graceful” close, ., that all outstanding data will be delivered ( )the connection is closed.