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OSI Model & TCPIP.pptx
- 1. FACULTY OF INFORMATION TECHNOLOGY PhD. LE TRAN DUC OSI MODEL & TCP/IP
- 2. 2 FACULTY OF INFORMATION TECHNOLOGY PhD. LE TRAN DUC LAYERING OF AIRLINE FUNCTIONALITY The airline functionalities are divided into layers Layers: each layer implements a service • by performing certain actions within that layer • relying on services provided by layer below Look at the functionality in a horizontal manner
- 3. 3 FACULTY OF INFORMATION TECHNOLOGY PhD. LE TRAN DUC WHAT IS A NETWORKING MODEL?
- 4. 4 FACULTY OF INFORMATION TECHNOLOGY PhD. LE TRAN DUC NETWORK WITHOUT STANDARDIZATION
- 5. 5 FACULTY OF INFORMATION TECHNOLOGY PhD. LE TRAN DUC OSI MODEL
- 6. 6 FACULTY OF INFORMATION TECHNOLOGY PhD. LE TRAN DUC OSI MODEL – APPLICATION LAYER
- 7. 7 FACULTY OF INFORMATION TECHNOLOGY PhD. LE TRAN DUC OSI MODEL – PRESENTATION LAYER
- 8. 8 FACULTY OF INFORMATION TECHNOLOGY PhD. LE TRAN DUC OSI MODEL – SESSION LAYER
- 9. 9 FACULTY OF INFORMATION TECHNOLOGY PhD. LE TRAN DUC OSI MODEL – THE UPPER LAYERS
- 10. 10 FACULTY OF INFORMATION TECHNOLOGY PhD. LE TRAN DUC OSI MODEL – THE TRANSPORT LAYER Đảm bảo end to end ko bị lỗi
- 11. 11 FACULTY OF INFORMATION TECHNOLOGY PhD. LE TRAN DUC OSI MODEL – THE NETWORK LAYER
- 12. 12 FACULTY OF INFORMATION TECHNOLOGY PhD. LE TRAN DUC OSI MODEL – THE DATA LINK LAYER
- 13. 13 FACULTY OF INFORMATION TECHNOLOGY PhD. LE TRAN DUC OSI MODEL – THE PHYSICAL LAYER
- 14. 14 FACULTY OF INFORMATION TECHNOLOGY PhD. LE TRAN DUC ENCAPSULATION Figure shows the physical path: - data takes down a sending end system’s protocol stack - up and down the protocol stacks of a link-layer switch and router - up the protocol stack at the receiving end system. A packet has two types of fields: header fields and a payload field. The payload is typically a packet from the layer above.
- 15. 15 FACULTY OF INFORMATION TECHNOLOGY PhD. LE TRAN DUC OSI MODEL – PDUs
- 16. 16 FACULTY OF INFORMATION TECHNOLOGY PhD. LE TRAN DUC OSI MODEL – ACCRONYMS
- 17. 17 FACULTY OF INFORMATION TECHNOLOGY PhD. LE TRAN DUC TCP/IP SUITE
- 18. 18 FACULTY OF INFORMATION TECHNOLOGY PhD. LE TRAN DUC OSI vs TCP/IP
- 19. 19 FACULTY OF INFORMATION TECHNOLOGY PhD. LE TRAN DUC TCP/IP SUITE
- 20. 20 FACULTY OF INFORMATION TECHNOLOGY PhD. LE TRAN DUC TCP/IP SUITE
- 21. 21 FACULTY OF INFORMATION TECHNOLOGY PhD. LE TRAN DUC INTERNET PROTOCOL STACK • Application: supporting network applications - FTP, SMTP, HTTP, DNS - The app. in one end system using the protocol to exchange message (packets of information) with the app. in another end system • Transport: process-process data transfer, flow control - TCP, UDP - Reliable end-to-end delivery service - Transport application-layer messages - Transport-layer packet = segment • Network: routing of IP packet from source to destination - Provides the service of delivering the segment through a series of routers to the transport layer in the destination host - IP, routing protocols • Link-layer: data transfer between neighboring network elements - To move a frame from one node to the next node in the route - Reliable delivery between 2 adjacent nodes - Ethernet, 802.11 (Wi-Fi), PPP • Physical: bits “on the wire” Move individual bits within the frame from one node to the next application transport network link physical
- 22. 22 FACULTY OF INFORMATION TECHNOLOGY PhD. LE TRAN DUC OSI REFERENCE MODEL • presentation: allow applications to interpret meaning of data, e.g., encryption, compression, machine- specific conventions • session: synchronization, checkpointing, recovery of data exchange • Internet stack “missing” these layers! - these services, if needed, must be implemented in application - needed? application presentation session transport network link physical
- 23. 23 FACULTY OF INFORMATION TECHNOLOGY PhD. LE TRAN DUC OSI REFERENCE MODEL
- 24. 24 FACULTY OF INFORMATION TECHNOLOGY PhD. LE TRAN DUC OSI REFERENCE MODEL
- 25. 25 FACULTY OF INFORMATION TECHNOLOGY PhD. LE TRAN DUC WIRESHARK Transport (TCP/UDP) Network (IP) Link (Ethernet) Physical application (www browser, email client) application OS packet capture (pcap) packet analyzer copy of all Ethernet frames sent/receive d
Hinweis der Redaktion
- Our goal: get “feel” and terminology more depth, detail later in course approach: use Internet as example
- Why layering? Dealing with complex systems: explicit structure allows identification, relationship of complex system’s pieces layered reference model for discussion modularization eases maintenance, updating of system change of implementation of layer’s service transparent to rest of system e.g., change in gate procedure doesn’t affect rest of system For example, if the gate functions were changed (for instance, to have people board and disembark by height), the remainder of the airline system would remain unchanged since the gate layer still provides the same function (loading and unloading people)
- To provide structure to the design of network protocols, network designers organize protocols—and the network hardware and software that implement the protocols— in layers. Each protocol belongs to one of the layers, just as each function in the airline architecture We are again interested in the services that a layer offers to the layer above—the so-called service model of a layer. One potential drawback of layering is that one layer may duplicate lower-layer functionality. For example, many protocol stacks provide error recovery on both a per-link basis and an end-to-end basis. A second potential drawback is that functionality at one layer may need information (for example, a timestamp value) that is present only in another layer; this violates the goal of separation of layers.
- OSI: Open Systems Interconnection Vì trong TCP/IP ko cần 2 layers này nảy sinh câu hỏi chúng có thực sự cần thiết ko? The TCP/IP model, which is realistically the Internet Model, came into existence about 10 years before the OSI model. The OSI model (Open Standards Institute) is an internationally accepted generic model for all new protocols to be designed around and older protocols -- such as TCP/IP -- to fit into. (ref: https://searchnetworking.techtarget.com/answer/Which-came-first-TCP-IP-or-OSI)
- Application layer: Performs services for the applications used by the end users Presentation layer: Formats (translation, compression, encryption) the data to be presented to the Application Layer Session layer: Manages sessions & maintains connection between users Transport layer: Defines data segments & transfers the data, ensures error-free, no losses & duplication Network layer: Creates & addresses IP packets for end-to-end delivery & routing Data link layer: Creates & addresses (MAC) frames for host-to-host delivery, provides error-free transfer Physical layer: Transmits binary data (bits) over physical medium between devices OSI: Open System Interconnection 1. Viết thư 2.Chèn nó vào một phong bì 3.Ghi thông tin về người gửi và người nhận trên phong bì 4.Dán tem cho nó 5.Đi đến bưu điện và thả nó vào một hộp thư Physical Layer: Cáp, khoảng cách, kỹ thuật truyền tín hiệu, speed… Lớp vật lý quy định các đặc điểm của 1 đường truyền vật lý về cơ điện quan, các thủ tục chức năng để làm sao truyền được dòng bit nhị phân đi Tóm lại là xây dựng được đường truyền vật lý cho các hosts. Data Link Layer: Sau khi đã có đường truyền vật lý rồi thì làm cách nào để dữ liệu từ các lớp bên trên có thể truy nhập vào đường truyền vật lý? Lớp liên kết dữ liệu Điểu khiển việc truy nhập vào đường truyền vật lý và giao tiếp với lớp network. Định dạng dữ liệu: đóng khung, cấu trúc khóa…; cung cấp cơ chế dò lỗi. Network Layer: có nhiều đường truyền vật lý thì đi đường nào tối ưu? Phân bố dữ liệu từ điểm này đến điểm kia (routing), địa chỉ định danh IP Transport Layer: 2 PC đã có thể đi tới nhau nhưng quản lý kết nối ra sao đây? End-to-end connections (ko quan tâm ở giữa gói tin đi ra sao), đảm bảo dữ liệu được truyền tải tin cậy. Thiết lập duy trì kết thúc các đường mạch ảo. Cung cấp cơ chế sửa lỗi dò lỗi phục hồi thông tin. Session Layer: truyền thông liên host Thiết lập duy trì kết thúc các phiên kết nối giữa các ứng dụng khác nhau. Presentation Layer: thông ngôn để 2 đầu gửi nhận hiểu nhau, format/structure data, mã hóa. Application Layer: Performs services for the applications used by the end users Example: https://www.youtube.com/watch?v=Cbqsm23zgMQ
- Bắt gói tin bằng wireshark rồi chỉ ra trên đó giao thức TCP/IP
- Bắt gói tin bằng wireshark rồi chỉ ra trên đó giao thức TCP/IP