超星 - chapter 1 written exercise update - 查题吧

简答题

9. Why is the Internet designed as a routed instead of a switched network? If it were designed as a switched network, what layers and mechanisms would need to be changed?9．为什么互联网被设计成路由式的而不是交换式的网络？如果它被设计成一个交换式的网络，则需要改变哪些层次和机制？

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10. Here we compare the overhead of routing packets and switching packets. Why is the time complexity of routing higher than switching, while the space complexity of switching is higher than routing?10．比较一下路由分组和交换分组的开销。为什么路由时间复杂度高于交换，而交换的空间复杂度要比路由的高？

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11. If a new routing protocol is to be supported in routers, what should be deifned as standard and what should be left as implementation-dependent design?11．如果要在路由器上支持新的路由协议，需要将那些内容定义为标准、那些内容应该留作实现与相关的设计？

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12. Content networking demands the Internet itself become more application-aware, i.e., knowing who is accessing what data and talking to whom, which would disrupt the original end-to-end argument. What changes may be brought into the network to support content networking?12．内容网络互连要求互联网本身成为更加具有应用感知的，即要求知道谁访问什么数据并与谁交流通话，但这会破坏原有的端到端观点。需要采取什么样的更改来支持内容网络互连？

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13. ATM (asynchronous transfer mode) and MPLS (multi-protocol label switching) do not have stateless core networks. What states do they keep? What is the main difference in the way they keep these states?13．ATM（异步传输模式）和MPLS（多协议标签交换）没有无状态的核心网络。他们保持了什么状态？他们保持这些状态的方式上有何主要区别？

简答题

14. ATM (asynchronous transfer mode) is an alternative technology for data communications. Why does it have high overhead when interoperating with IP to carry IP packets?14．ATM（异步传输模式）是一种用于数据通信的可选技术。为什么当它与IP互操作承载传输IP数据包时具有很高的开销？

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15. MPLS (multi-protocol label switching) is a standard for IP switching that aims to switch most but route few IP packets. What is the barrier to its deployment? How can we reduce the effect of this barrier?15．MPLS（多协议标签交换）是IP交换的一种标准，旨在交换多数但路由少数的IP数据包。将其实施的障碍是什么？如何减少这一障碍的影响？

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16. When supporting a protocol, we may put the protocol entity into the kernel or a daemon process. What are the considerations here? That is, when will you put it into the kernel and a daemon, respectively?16．当支持某个协议时，我们可能将协议实体放入内核或守护进程中。这里需要考虑什么？也就是说，分别在什么时候将协议实体放入内核和守护进程？

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21. Linux, apache, sendmail, GNU C library, bind, freeS/wan, and snort are popular open source packages. Search on the Internet to find out the license model for each of them, and summarize the differences between these license models.21．Linux、Apache、sendmail、GNU C库、bind、FreeS/WAN和Snort是流行的开源软件包。在互联网上搜索它们的许可证模式，并概括这些许可证模式之间的差异。

简答题

22. When you type in a URL at your browser, you get the corresponding homepage within seconds. Briefly describes what happened at your host, the intermediate routers, and the related server, respectively. Read Section 1.5.2 before writing your answers so that your answer is precise, but do not assume you are running on Linux systems.22．当用户在浏览器中输入一个URL时，会在几秒钟内得到相应的网页。分别简要描述在主机、中间路由器以及相关的服务器上会发生什么。书写答案之前为了使你的答案更为准确，参阅第1.5.2节，但不一定要求运行在Linux系统之上。

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