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  • [Computer Networking] {CMU14-740} Lecture 5: The Application Layer -- HTTP

     

    We begin our examination of the application layer with one of the most ubiquitous application protocols: the Hypertext Transport Protocol. We will tear into the protocol's formats, the sequence of message transmissions, the different connection methods and lots of use case information.

    Lesson Objectives

    By the end of this lesson, the student will be able to:

    • describe the mission, scope, addressing mechanism and data types of the Application Layer.
    • explain the HTTP protocol, including message format, interaction model and connection management.
    • calculate response time for an HTTP request over nonpersistent, parallel or persistent connections, including the pipelined variant.
    • describe how web proxies work to cache HTTP responses, including how they ensure consistency.

    Reading

    • KR Ch 2.1 - 2.2

    Slides

    Video


     

    transport layer -> TCP or UDP

    TCP:

    UDP => directly send message

    TCP => demand stability


    https://searchnetworking.techtarget.com/answer/How-are-TCP-IP-and-HTTP-related


     

     

     

     BNF => formal mechanism describe how the bit should be

     

    CRLF => end of the line

     https://stackoverflow.com/questions/1552749/difference-between-cr-lf-lf-and-cr-line-break-types

    SP => space

     

    connection close => fetching data finished

     

    .............

     

     

     

     

    Nonpersistent => primitive version => inefficient

     

    What if by parallel??

     

    eg. require four pictures => 4 pictures loading at the sam time => feel faster but actually slower

    another issue with parallel TCP request:

     Better solution: keep the TCP connection open

     

     

     

    proxy server saves cache for faster website visiting

    classic caching problem: lead to consistency problem => how do you know there's no change in the remote server?

     

     

     

     


    https://zhuanlan.zhihu.com/p/60450391

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  • 原文地址:https://www.cnblogs.com/ecoflex/p/10962439.html
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