软件水平考试

【单选题】Networks can be interconnected by different devices．In the physical layer，networks can be connected by (66) or Hubs, which just move the bits from one network to an identical net-work. One layer up we find bridgas and swiehes, which operate at data link layer. They can accept (67) , examine the MAC、address, and forward the frames to a different network while doing minor protocol translation in the process. In the network layer, we have routers that can connect two netwoks. If two networks have (68) network layer, the router may be able to translate between the packet formats. In the transport layer we find transport gateway, which can interface between the two transport connections. Finally, in the application layer, application gateways translate message
(69) .As an example, gateways between Internet e-mail and X.400 e-mail must (70) the e-mail message and change various header fields.
A．syntax
B．semantics
C．languages
D．format

网考网参考答案：A
网考网解析：
暂无解析 document.getElementById("warp").style.display="none"; document.getElementById("content").style.display="block"; 查看试题解析出处>>