Layer 5,6,7 of the OSI model

1. Protocol Stack and Addressing Team CharMusafirs AnkanAdhikari [1MS07IS010] Chandan Kumar [1MS07IS019] Chandresh Kumar [1MS07IS020] Pawan Kumar [1MS07IS065]

2. OSI Model Overview of the OSI model

3. OSI Model Application Layer 1.Application layer interacts with application programs and is the highest level of OSI model. 2. Application layer contains management functions to support distributed applications. 3. Application layer functions typically include identifying communication partners, determining resource availability, and synchronizing communication. 4. Examples of application layer are applications such as file transfer, electronic mail, remote login etc.

4. 4 Application layer Protocols OSI Model DHCP [Dynamic Host Configuration protocol] Provides static/dynamic address allocation, both manual and automatic. Dynamic : Assigns IP address for a specified time (lease time) Needed when a host moves from network to network or is connected/disconnected from a network. DHCP server keeps a table of past IP address assignments, so that it can preferentially assign to a client the same IP address that the client previously had.

5. OSI Model PRESENTATION LAYER The presentation layer ensures that the information that the application layer of one system sends out is readable by the application layer of another system. If necessary, the presentation layer translates between multiple data formats by using a common format. Provides encryption and compression of data. Examples :- JPEG, MPEG, ASCII, EBCDIC, HTML , AFP, ICA, LPP,NCP, NDR,RDP,XDR,X.25 PAD.

6. OSI Model PRESENTATION LAYER PROTOCOL ASCII (American Standard Code for Information Interchange ) ASCII is a character-encoding scheme based on the ordering of the English alphabet. ASCII codes represent text in computers, communications equipment, and other devices that use text. ASCII includes definitions for 128 characters: 33 are non-printing control characters that affect how text and space is processed; 94 are printable characters, and the spaces is considered an invisible graphic. HTML (Hyper Text Markup Language) HTML is the predominant markup language for web pages. It provides a means to create structure documents by denoting structural semantics for text such as headings, paragraphs, lists etc as well as for links, quotes, and other items. It allows images and objects to be embedded and can be used to create interactive forms.

7. OSI Model SESSION LAYER The session layer defines how to start, control and end conversations (called sessions) between applications. This includes the control and management of multiple bi-directional messages using dialogue control. It also synchronizes dialogue between two hosts' presentation layers and manages their data exchange. The session layer offers provisions for efficient data transfer. Examples :- SQL, ASP, ADSP,ASP,.ISO-SP, OSI, L2F, L2TP, NetBIOS

8. OSI Model SESSION LAYER PROTOCOL SSH (Secure Shell) SSH is a protocol for creating a secure connection between two systems. In the SSH protocol, the client machine initiates a connection with a server machine. SSH uses public-key cryptography to authenticate the remote computer and allow the remote computer to authenticate the user, if necessary.

9. 9 OSI and Protocol Stack OSI: Open Systems Interconnect OSI Model TCP/IP Hierarchy Protocols 7th Application Layer 6th Presentation Layer Application Layer 5th Session Layer 4th Transport Layer Transport Layer Network Layer 3rd Network Layer 2nd Link Layer Link Layer 1st Physical Layer Link Layer : includes device driver and network interface card Network Layer : handles the movement of packets, i.e. Routing Transport Layer : provides a reliable flow of data between two hosts Application Layer : handles the details of the particular application

11. OSI Model MAC Spoofing Emulating MACs for illegal access. HKEY_LOCAL_MACHINEYSTEMurrentControlSetontrollass4D36E972-E325-11CE-BFC1-08002BE10318} contains driver information. DriverDesc contains the Adapter’s information, Adding a NetworkAddress key. 3rd party tools: MadMACs, MacMakeUp. Loosely possible to DDoS.