The two most recognized network reference models are: The Open Systems Interconnection (OSI) model • The Department of Defense (DoD) model Without the framework that network models provide, all network hardware and software would have been proprietary. Organizations would have been locked into a single vendor’s equipment, and global networks like the Internet would have been impractical, if not impossible. Network models are organized into layers, with each layer representing a specific networking function. These functions are controlled by protocols, which are rules that govern end-to-end communication between devices.
Protocols on one layer will interact with protocols on the layer above and below it, forming a protocol suite or stack. The TCP/IP suite is the most prevalent protocol suite, and is the foundation of the Internet. A network model is not a physical entity – there is no OSI device. Manufacturers do not always strictly adhere to a reference model’s blueprint, and thus not every protocol fits perfectly within a single layer. Some protocols can function across multiple layers. *** All original material copyright © 2012 by Aaron Balchunas ( com), unless otherwise noted.
The Essay on Osi Reference Model Session Layer
The OSI layers (from the bottom up) are as follows: Physical: Transmits data Data Link: Corrects transmission errors Network: Provides the physical routing information Transport: Verifies that data is correctly transmitted Session: Synchronizes data exchange between upper and lower layers Presentation: Converts network data to application-specific formats Application: End-user interface The ...
All other material copyright © of their respective owners. This material may be copied and used freely, but may not be altered or sold without the expressed written consent of the owner of the above copyright. Updated material may be found at http://www. routeralley. com. OSI Reference Model v1. 21 – Aaron Balchunas 2 OSI Reference Model The Open Systems Interconnection (OSI) model was developed by the International Organization for Standardization (ISO), and formalized in 1984. It provided the first framework governing how information should be sent across a network.
