What are the evaluations (properties) of an OSI model layer?

The question is not clear but still i would like to define properties comparing OSI with TCP/IP.....hope this is the answer.

First of all OSI came after TCP/IP but OSI did not take over the world due to some reasons

1. Bad timing

2. Bad Technology

3. Bad Implementations and

4. Bad Politcs.

On the other hand despite of being there is no Data Link layer,  Session layer and the  Presentation layer TCP/IP became successful just because some of its features

1. Numbering System (keeps track of segment)

2. Flow Control

3. Error Control

4. Connection control (due to various handshaking methods and connection termination)

 

 

good

1.OSIprotocolsstacks are split into seven layers.2.The layers form a hierarchy of functionality starting with the physical hardware components to the user interfaces at the software application level.3. Each layer receives information from the layer above, processes it and passes it down to the next layer.4.Each layer adds its own encapsulation information (header) to the incoming information before it is passed to the lower layer.5. Headers generally include address of destination and source, check sums (for error control), type of protocol used in the current layer, and other options such as flow control options and sequence numbers.

Layer1: The Physical Layer

The Physical Layer describes physical properties of the media, such as the electrical properties and interpretation of exchanged signals.

 

Layer2: The Data Link Layer

The Datalink Layer describes the logical organization of data bits transmitted on a particular medium, for example the logical addressing of Ethernet packets.

 

Layer3: The Network Layer

The Network Layer describes how a series of exchanges over various data links can deliver data between any two nodes in a network; basically describing how packets get routed through the 'net.

 

Layer4: The Transport Layer

The Transport Layer describes the quality and nature of the data delivery.

 

Layer5: The Session Layer

The Session Layer describes the organization of data sequences larger than the packets handled by the lower layers. Basically, its the job of the Session Layer to fix what the other layers have screwed up.

 

Layer6: The Presentation Layer

The Presentation Layer describes the syntax of data being transferred for communication with dissimilar systems.

 

Layer7: The Application Layer

The Application Layer describes how real work actually gets done; its the reason we do things in the first place.

 

 

 IF I understand your question each layer of the OSI model exists as an independent module. In theory, you can substitute one protocol for another at any given layer without affecting the operation of layers above or below.

The design of the OSI model is based on the following principles:

1. A layer should be created only when an additional level of abstraction is required.

2. Each layer should perform a well-defined function.

3. The function of each layer should be chosen with the goal of defining internationally standardized protocols.

4. The layer boundaries should be chosen to minimize the information flow across the interfaces.

The number of layers should be large enough to enable distinct function to be seperated .

OSI CONTAIN7LAYER AS FOLLOW:

• APPLICATION: end user application protocals
• PRESENTATION: second time of coding data to be understood by the application and end user
• SESSION : start and ending the transfering session
• TRANSPORTATION : the transferining of the data either udp or tcp>
• NETWORK : it take care about the route that the signal takes to reaches the distanation
• DATALINK : it take care of the protocals and changing the signal on the way that the chanel in the physical layer can handle.
• PHYSICAL: refer to the link between the transport and reciver.