1 / 29

Lab312

Lab312. Lab312 專題生暑假需知. 每一課程都會有作業 且點名與作業表現將影響專題生是否能續留本實驗室 修習本實驗室之專題生務必要出席 在開學前會公告 final project 的機測時間，詳細資訊請看 Room312 板 點名 + 課程作業 +final project 此為續留本實驗室之條件 缺一不可. protocol. 大概說說 TCP 大概說說 HTTP. TCP. Transmission Control Protocol point-to-point: one sender, one receiver

rafi
Download Presentation

Lab312

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Lab312

  2. Lab312 專題生暑假需知 • 每一課程都會有作業 • 且點名與作業表現將影響專題生是否能續留本實驗室 • 修習本實驗室之專題生務必要出席 • 在開學前會公告final project的機測時間，詳細資訊請看Room312板 • 點名+課程作業+final project 此為續留本實驗室之條件 缺一不可

  3. protocol • 大概說說 TCP • 大概說說HTTP

  4. TCP • Transmission Control Protocol • point-to-point: • one sender, one receiver • reliable, in-order byte steam: • no “message boundaries • connection-oriented: • handshaking (exchange of control msgs) init’s sender, receiver state before data exchange

  5. TCP • Transmission Control Protocol

  6. TCP

  7. TCP

  8. 32 bits source port # dest port # sequence number acknowledgement number head len not used Receive window U A P R S F checksum Urg data pnter Options (variable length) application data (variable length) TCP URG: urgent data (generally not used) counting by bytes of data (not segments!) ACK: ACK # valid PSH: push data now (generally not used) # bytes rcvr willing to accept RST, SYN, FIN: connection estab (setup, teardown commands) Internet checksum (as in UDP)

  9. time TCP Seq. #’s: • byte stream “number” of first byte in segment’s data ACKs: • seq # of next byte expected from other side • cumulative ACK Q: how receiver handles out-of-order segments • A: TCP spec doesn’t say, - up to implementor Host B Host A User types ‘C’ Seq=42, ACK=79, data = ‘C’ host ACKs receipt of ‘C’, echoes back ‘C’ Seq=79, ACK=43, data = ‘C’ host ACKs receipt of echoed ‘C’ Seq=43, ACK=80 simple telnet scenario

  10. www.someschool.edu/someDept/pic.gif path name host name HTTP • Hypertext Transfer Protocol • Web page consists of objects • Object can be HTML file, JPEG image, Java applet, audio file,… • Web page consists of base HTML-file which includes several referenced objects • Each object is addressable by a URL • Example URL:

  11. HTTP HTTP: hypertext transfer protocol • Web’s application layer protocol • client/server model • client: browser that requests, receives, “displays” Web objects • server: Web server sends objects in response to requests • HTTP 1.0: RFC 1945 • HTTP 1.1: RFC 2068 HTTP request PC running Explorer HTTP response HTTP request Server running Apache Web server HTTP response Mac running Navigator

  12. HTTP Request Message • two types of HTTP messages: request, response • HTTP request message: • ASCII (human-readable format) request line (GET, POST, HEAD commands) GET /somedir/page.html HTTP/1.1 Host: www.someschool.edu User-agent: Mozilla/4.0 Connection: close Accept-language:fr (extra carriage return, line feed) header lines Carriage return, line feed indicates end of message

  13. HTTP Request Message

  14. HTTP Method HTTP/1.0 • GET • POST • HEAD • asks server to leave requested object out of response HTTP/1.1 • GET, POST, HEAD • PUT • uploads file in entity body to path specified in URL field • DELETE • deletes file specified in the URL field

  15. HTTP Response Message status line (protocol status code status phrase) HTTP/1.1 200 OK Connection close Date: Thu, 06 Aug 1998 12:00:15 GMT Server: Apache/1.3.0 (Unix) Last-Modified: Mon, 22 Jun 1998 …... Content-Length: 6821 Content-Type: text/html data data data data data ... header lines data, e.g., requested HTML file

  16. HTTP Response Status Codes In first line in server->client response message. A few sample codes: 200 OK • request succeeded, requested object later in this message 301 Moved Permanently • requested object moved, new location specified later in this message (Location:) 400 Bad Request • request message not understood by server 404 Not Found • requested document not found on this server 505 HTTP Version Not Supported

  17. WireShark • Wireshark（前稱Ethereal）是一個網路封包分析軟體。網路封包分析軟體的功能是擷取網路封包，並盡可能顯示出最為詳細的網路封包資料。

  18. 安裝 WireShark • http://www.wireshark.org/

  19. 安裝 WireShark

  20. 安裝 WireShark

  21. 安裝 WireShark

  22. 安裝 WireShark

  23. 安裝 WireShark

  24. WireShark

  25. WireShark

  26. WireShark

  27. WireShark

  28. WireShark

  29. 作業一 • 1.利用wireshark錄製連線封包，並標出three way handshake步驟的幾個封包。 • 2.找出TCP Header中Sequence number以及Acknowledgment number欄位是做什麼用途，在連線過程中裡面的內容代表什麼意義，請清楚說明。 • Mail到 hsien0714@gmail.com • mail標題:Lab312作業一 • Mail內容:請包含學號、姓名。 • Due:8/4

More Related