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1.27.Which of the following statements are correct for the “transport layer” in the OSI 7-layer model ?
下列哪些對於OSI 七層架構中”傳輸層”的敘述是正確的?
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| (a)It deals with the problem of how to transmit packets between a pair of processes in different hosts. 它負責處理如何在不同主機上一對行程間的封包傳輸問題。 | |
| (b)The User Datagram Protocol (UDP) is a transport layer protocol that provides reliable transmission service. UDP協議是一個提供可靠傳輸服務的傳輸層協議。 | |
| (c)The Transmission Control Protocol (TCP) is a transport layer protocol that provides reliable transmission service. TCP協議是一個提供可靠傳輸服務的傳輸層協議。 | |
| (d)Routers usually not implement transport layer protocols. 路由器通常不實作傳輸層協議。 | |
| (e)Transport layer protocols usually are only implemented in end hosts. 傳輸層協議通常只實作在終端主機上。 |
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1.28.Which of the following are the main features of the Internet Architecture ?
下列哪些是互聯網架構的主要特色?
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| (a)Strict layering. The layer N protocol is only allowed to use the services provided by layer N-1 protocol. 嚴格分層。第N層協議只允許使用由N-1層協議所提供的服務。 | |
| (b)Not strict layering. The layer N protocol is allowed to use the services provided by layer N-2 protocol or other underlying protocols directly. 不嚴格分層。第N層協議允許使用由N-2層或更底層協議所提供的服務。 | |
| (c)An hour-glass shape of protocols and IP serves as the focal point for the architecture 為沙漏狀架構, 而 IP 協議為此結構的中心點。 | |
| (d)An hour-glass shape of protocols and TCP/UDP serves as the focal point for the architecture. 為沙漏狀架構, 而 TCP/UDP協議為此結構的中心點。 | |
| (e)In order for a new protocol to be officially included in the architecture, there needs to be both a protocol specification and at least one representative implementations of the specification. 為了在此架構上新增加一個協議,我們需要同時具備一個協定規範與至少一個代表性的實作。 |