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Cs 6250 computer networking lecture 8 content

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information, you could, of course, compute the statistic yourself.
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CS 6250: Computer Networking Lecture 8: Content Distribution Lesson 3 Intro We've covered congestion control, which works within network protocols; traffic shaping, which is a high level network tool; and now we'll look at content distribution, an internet-wide tool that enables websites and network operators to deliver data quickly and efficiently. And to wrap up this section of the course, your project will export TCP in its slow start state. The Web and Caching In this lesson, we'll talk about the web and how web caches can improve web performance. We will study, in particular, the hyper-text transfer protocol, or HTTP, which is an application layer protocol to transfer web content. It's the protocol that your web browser uses to request web pages, and it's also the protocol that the responses (or the web pages, or the objects that are returned as part of a webpage) are returned to your browser. Your web browser makes requests for web pages, and the pages and the objects in the page come back as responses. HTTP is typically layered on top of a byte stream protocol, which is almost always TCP. The client sends a request to a server asking for web content and the server responds with the content often encoded in text. The server maintains no information about past client requests. Thus we say the server is stateless. Let's take a quick look into the format of HTTP requests, and responses.
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HTTP Requests Let's first take a look at the contents of an HTTP Request. First there's the Request Line which typically indicates first, a method of request, where typical methods get to return the content associated with the URL; a Post, which sends data to the server; and a Head Request which returns, typically, only the headers of the Get Response, but not the content. It's worth noting that a Get Request can also be used to send data from the content to the server. The request line also includes the URL, which is relative, and may be something like index.HTML, and it also includes the version number of the HTTP protocol. The request also contains additional headers, many of which are optional. These include the referrer, which indicates the URL that caused the page to be requested. For example, if an object is being requested as part of embedded content in another page, the referrer might be the page that's embedding the content. Another example header is the user agent, which is the client software that's being used to fetch the page. For example, you might fetch a page using a particular version of Chrome or Firefox, and the user agent informs the server which client software is being used. Example HTTP Request
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Let's take a look at an example HTTP request now. You can see here the request line, and here are some headers. Accept indicates that the client's willing to accept any content type, that it would like the content to be returned in English, that it can accept pages that are encoded in particular compression formats. We talked about the user agents. So in this case, it's a Mozilla 5.0 browser. Here's the host that the request is being made to. This is particularly useful in cases
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  • Fall '08
  • Staff
  • IP address, Transmission Control Protocol

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