Layer Responsible for reliable connection?

Which OSI layer is responsible for establishing a reliable connection?

I originally thought that the Sesson Layer (per the notes on this site) was the answer but my prep-test says that the Transport Layer is correct. I'm trying to logically think through this. If the Session Layer establishes, maintains and terminates connections why isn't the Session Layer the anwser? Is the key work 'RELIABLE'. The Transport layer has connection-oriented protocals.

Can someone explain or clarify this?

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viper75

chemaster wrote:

Which OSI layer is responsible for establishing a reliable connection?

I originally thought that the Sesson Layer (per the notes on this site) was the answer but my prep-test says that the Transport Layer is correct. I'm trying to logically think through this. If the Session Layer establishes, maintains and terminates connections why isn't the Session Layer the anwser? Is the key work 'RELIABLE'. The Transport layer has connection-oriented protocals.

Can someone explain or clarify this?

The keyword is "RELIABLE" The answer to your question is The Transport Layer, TCP and UDP hang out there.

jamtech

The session layer is only responsible for the opening/termination of the circuit/connection. The transport layer using protocol such as TCP is responsible for the reliability of the packets. It does the error checking, which the session layer does not provide. Just remember that the session layer does not transport packets.

Well, you get it just keep studying.....the guys here will provide more knowledge!.

Webmaster

chemaster wrote:

Which OSI layer is responsible for establishing a reliable connection?

I originally thought that the Sesson Layer (per the notes on this site) was the answer but my prep-test says that the Transport Layer is correct.

www.techexams.net/technotes/networkplus/osimodel.shtml
I think you'll need to read a little better

Establishes, maintains and terminates end-to-end connections (sessions) between two applications on two network nodes. It controls the dialogue between the source and destination node, which node can send when and how long. Also provides error reporting for the Application, Presentation and Session layer.

To put it simple: the session layer works for the upper layers (software application) and the transport layer works for the lower layers, the network protocol.

Which OSI layer is responsible for establishing a reliable connection?

is actually an incomplete question, as even the Data Link layer does that (FCS). It should indicate what the connection connect (basically applications or network devices). In case you would get this question litteraly on an exam, the answer is Transport layer, because that one is most commonly identified with 'reliable connections' (see part about 'connection-oriented' in my OSI notes.)

Not that the layers work largely indepently of each other (modular model) which means that if one layer performs a general task/concept it doesn't mean another layer can't do something similar. It all depends on for who the layer is performing that task.

I hope this clears it up. It's a common confusion and if I remember correctly there are several older post (net+ or CCNA forum) in which it is explained in more detail.

crabeater

Johan,
I never noticed before:
In the SESSION layer, your last comment is :
Protocols at this layer - RPC, NetBIOS

I can not find RPC listed anywhere else (a Find search gave only this comment). To which Network OS are you refering?

Webmaster

I can not find RPC listed anywhere else (a Find search gave only this comment). To which Network OS are you refering?

I'm referring to Remote Procedure Calls (RPC), a protocol that allows a client to run programs on a remote server. If you run Windows XP (or NT 4 or 2000), open Services and you will see the services for RPC.