25-08-2017, 09:32 PM
OSI Reference Model
OSI Reference Model.ppt (Size: 2.05 MB / Downloads: 41)
Open Systems Interconnection (OSI) reference model was created by the International Organization. For Standardization. It is a conceptual blueprint of how communications should take place.These processes divides into logical groupings called layers.When a communication is designed in this manner, it’s known as layered architecture.
Advantages of Reference Models
Allows multiple-vendor development through standardization of network components.
Allows various types of network hardware and software to communicate.
Prevents changes in one layer from affecting other layers, so it does not hamper development.
Dividing the complex network operation into more manageable layers.
Application Layer
Layer 7 defines the interface between the communications software and any applications that need to communicate outside the computer on which the application resides.
Eg: WWW, FTP, Telnet, HTTP, NFS, Browsers, SNMP, SMTP, TFTP, DNS, DHCP, BOOTP
Transport Layer
Layer-4 focuses on issues related to data delivery to the other computer-for instance, error recovery, provide congestion avoidance, overloading, data loss, segmentation of large application data blocks into smaller ones for transmission, and reassembly of those blocks of data on the receiving computer called flow control. Ensure that segment delivered will be acknowledgement back to the sender called windowing. It provide for retransmission of any segment that are not acknowledged.
Eg: TCP, UDP