The 7 OSI Layers

 

 

 

The OSI stands for Open System Interconnection which is used as a reference to help create a standardized model for network protocols by means of which utterly completely different distributors could easily support. This reference model is actually used as some extent of reference for protocol specs on account of being additional granular than the TCP/IP Protocol Architecture.

 

The OSI mannequin comprises 7 layers in comparison with the four layers in the TCP/IP model. Moreover creating interoperability between different vendors, this mannequin provides other advantages as well. The 7 layer model is easier to study due splitting the completely different layers into smaller parts unlike the 4 layer model.

 

The OSI model consists of the following 7 layers:

 

* Application - This layers primary operate is to provide communication between the communication software program and the functions which are used on the precise computer itself. An example contains consumer authentication

 

* Presentation - This particular layer determines the totally completely different information codecs together with encryption. An example comprises defining ASCII textual content, JPEG picture files, and binary.

 

* Session - The intention of the session layer is to outline easy methods to start, management, and end conversations. That is used also for bidirectional messages between applications.

 

* Transport - Controls and focuses on how information is delivered from one community device to another. this consists of processes reminiscent of error restoration and movement control. Each the TCP and UDP protocols function at this level.

 

* Network - Gives routing, addressing, and path determination. This protocol is responsible to how community items forward packets to their destination. IP is a protocol used at this layer and can be the protocol you examine primarily essentially the most about all through your CCNA studies.

 

* Data Hyperlink - Determines how devices ship and obtain over a particular medium. The Data Link layer defines the header and trailer format of data. Frame Relay, PPP, and Ethernet uses this protocol extensively.

 

* Bodily - This layer is apprehensive with the bodily connection of the particular transferring medium, just like CAT 5 cables.

 

The OSI mannequin is one a very powerful matters in your CCNA as all of the networking technologies you learn work on one or more layers throughout the OSI model. Utilizing this reference mannequin will help perceive why sure applied sciences such as Body Relay and Routing Protocols work the way do.