what "presentation layer" does in computer n/w?

Question

plz tell the work of presentation layer ASAP.
thanks

Answer 1

The presentation layer is the sixth level of the seven layer OSI model. It responds to service requests from the application layer and issues service requests to the session layer.

The presentation layer is responsible for the delivery and formatting of information to the application layer for further processing or display. It relieves the application layer of concern regarding syntactical differences in data representation within the end-user systems. Note: An example of a presentation service would be the conversion of an EBCDIC-coded text file to an ASCII-coded file.

The presentation layer is the first one where people start to care about what they are sending at a more advanced level than just a bunch of ones and zeros. This layer deals with issues like how strings are represented - whether they use the Visual Basic method ("13,thisisastring") or the C/C++ method ("thisisastring\0"). The idea is that the application layer should be able to point at the data to be moved, and the Presentation layer will deal with the rest.

Encryption is typically done at this level too, though it can be done at the application, session, transport, or network layer; each having its own advantages and disadvantages. Another example is representing structure, which is normally standardised at this level, often by using XML. As well as simple pieces of data, like strings, more complicated things are standardised in this layer. Two common examples are 'objects' in object-oriented programming, and the exact way that streaming video is transmited.

In many widely used applications and protocols, no distinction is made between the presentation and application layers. For example, HTTP, generally regarded as an application layer protocol, has presentation layer aspects such as the ability to identify character encodings for proper conversion, which is then done in the application layer.

Answer 2

The presentation layer is the sixth level of the seven layer OSI model. It responds to service requests from the application layer and issues service requests to the session layer.

The presentation layer is responsible for the delivery and formatting of information to the application layer for further processing or display. It relieves the application layer of concern regarding syntactical differences in data representation within the end-user systems. Note: An example of a presentation service would be the conversion of an EBCDIC-coded text file to an ASCII-coded file.

The presentation layer is the first one where people start to care about what they are sending at a more advanced level than just a bunch of ones and zeros. This layer deals with issues like how strings are represented - whether they use the Visual Basic method ("13,thisisastring") or the C/C++ method ("thisisastring\0"). The idea is that the application layer should be able to point at the data to be moved, and the Presentation layer will deal with the rest.

Encryption is typically done at this level too, though it can be done at the application, session, transport, or network layer; each having its own advantages and disadvantages. Another example is representing structure, which is normally standardised at this level, often by using XML. As well as simple pieces of data, like strings, more complicated things are standardised in this layer. Two common examples are 'objects' in object-oriented programming, and the exact way that streaming video is transmited.

In many widely used applications and protocols, no distinction is made between the presentation and application layers. For example, HTTP, generally regarded as an application layer protocol, has presentation layer aspects such as the ability to identify character encodings for proper conversion, which is then done in the application layer.

The presentation layer is concerned with the representation (syntax) of the data in the messages associated with an application during the transfer between two application processes. The aim is to ensure that the messages exchanged between two application processes have a common meaning - known as shared semantics - to both processes. The presentation layer is also concerned with data encryption and data security

Answer 3

The 7 layer OSI model has never really been adopted for use in the IP world. You have to remember that the 4-layer DoD IP model was already in existance and use when the 7 layer model was developed. Never really made sense to go back and actually try to refit it for the 7 layer model, so in most IP communications some of the layers are typically not present. Although people will still try to chop things up so that they can fit it into 7 layers......

Thats why it seems so confusing and why you get all htese cut & paste responses. No one in the newtworking field ever uses or talks about the presentation layer.

Answer 4

This layer (the 6th layer of the OSI model) determines how the file is presented to the user. This is the extension like *.jpg, *.bmp, *.doc, *.xls, etc. Determines the format of the file.

Answer 5

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Answer 6

http://www.google.com/search?hl=en&q=osi+model+presentation+layer&btnG=Google+Search