Session Layer And Transport Layer.

mohamedshajid

Hello guys i need to knew about the two major optional Topic on OSI layers.

• Session Layer
• Transport Layer

Session layer there is modes like - Simplex, Half Duplex, Full Duplex I've need to know what are the things are and what does? Specially i need a basic example for real world scenario.

Transport layer there is a chart is like that.
Flow Control --> Connection Oriented Communication --> Windowing --> Acknowledgements.

Please give me some points for all of this modes and charts. Thanks in advance.

Ivanjam

mohamedshajid, please remind me - what book(s) are you studying on the subject?

mohamedshajid

I'm currently having my CCNA Todd lammle's Guide actually there is deep chapters are there to follow.

W Stewart

mohamedshajid wrote: »

Hello guys i need to knew about the two major optional Topic on OSI layers.

• Session Layer
• Transport Layer

Session layer there is modes like - Simplex, Half Duplex, Full Duplex I've need to know what are the things are and what does? Specially i need a basic example for real world scenario.

Transport layer there is a chart is like that.
Flow Control --> Connection Oriented Communication --> Windowing --> Acknowledgements.

Please give me some points for all of this modes and charts. Thanks in advance.

Simplex means a device is either capable of listening or speaking. If it can do one it will never be capable of the other. A megaphone is an example of simplex. You can only speak through it. Not listen. Half duplex means you can listen or speak, just not at the same time. Walkie Talkies would be half duplex. Only one person at a time can talk on them because data can only flow in one direction at a time. From what I remember, all wireless devices operate in half duplex as well. Full duplex would mean that you can speak and listen at the same time. The only example I can give you on that one is ethernet. It can transmit and receive data at the same time. I don't know anything about models and charts other than the OSI model so I can't help you there.

mohamedshajid

Thanks mate that's correct notes for me. you great ::D

W Stewart

Actually I didn't realize you were talking about the transport layer with that model stuff. Basically TCP and UDP operate at the transport layer. I believe TCP is connection oriented which means it establishes a connection through a 3 way handshake before transmitting data where as UDP is connectionless and will just transmit the data without establishing a connection first. Basically host A sends host be a SYN (Synchronize) packet. Host B then sends host A a SYN ACK(Synchronize Acknowledgement) packet. Host A then sends host B an ACK packet. The connection is then established. That has to be done before data can be transferred and all that good stuff. As far as windowing and flow conrol. Basically the computer receiving the data sends a window size in the acknowledge packet. The computer sending data will send data until it reaches that window size. It will then stop sending packets until it receives an acknowledgement so it knows that the receiving end has received all of the packets.

Had to actually look up windowing since I couldn't remember it.

W Stewart

mohamedshajid wrote: »

Hmmm in other words i just completed session layer, Now transport layer, Anyone tell briefly three way handshakes to connection established.

Not sure what you just said. Was that a question?

mohamedshajid

W Stewart wrote: »

Actually I didn't realize you were talking about the transport layer with that model stuff. Basically TCP and UDP operate at the transport layer. I believe TCP is connection oriented which means it establishes a connection through a 3 way handshake before transmitting data where as UDP is connectionless and will just transmit the data without establishing a connection first. Basically host A sends host be a SYN (Synchronize) packet. Host B then sends host A a SYN ACK(Synchronize Acknowledgement) packet. Host A then sends host B an ACK packet. The connection is then established. That has to be done before data can be transferred and all that good stuff. As far as windowing and flow conrol. Basically the computer receiving the data sends a window size in the acknowledge packet. The computer sending data will send data until it reaches that window size. It will then stop sending packets until it receives an acknowledgement so it knows that the receiving end has received all of the packets.

Had to actually look up windowing since I couldn't remember it.

Yes Stewart You made me to realize how is the process of three way of handshake,Great post brother. thank you very much ..

mohamedshajid

Windows are used to control the amount of outstanding, Unacknowledged data segments. - From 7th Edition CCNA Todd Lammle (19 th Page)

W Stewart

mohamedshajid wrote: »

Yes Stewart You made me to realize how is the process of three way of handshake,Great post brother. thank you very much ..

no problem. working night shift at the NOC and have a lot of free time so I'm just studying myself.

mohamedshajid

W Stewart wrote: »

no problem. working night shift at the NOC and have a lot of free time so I'm just studying myself.

Ohhh! Stewart You're very impressed me because i have a lot of times to study because i don't even work as night shift or day night bro. That's better to study by myself it will be get more experience.. I should thanks to this forum to meet more wonderful peoples like u and more others.