I am trying to understand encapsulation of OSI model, in general it is quite clear for me but I have one question.
Please look on this picture http://www.just2good.co.uk/images/gif/ethernetFrame.gif
Default ethernet frame. And this is good picture for my question. You can see that IP encapsulation is shown.
As I understand
data part of
Ethernet frame is from 46 bytes to 1500 bytes length. This mean that for upper layer protocol there is only 1500-46 = 1454 bytes. Okay.
My question is : this all means that packet size decreasing according with level number, I mean that network layer have packet size < link layer And so on, because of encapsulation
data part of packet is decreasing, am I right ?
But why I have found that TCP packet size is for example 64kBytes !!!
How is it possible if we have
1454 bytes for data (minus headers of upper layer) on the
data link layer ?????
Please explain this for me, I would be very grateful.