Hi everybody im a little bit confused about how routers (ethernet and wireless) and data cables such as RJ45 could handle and manage the huge data and requests at same time thank u for answering ^^ !

Wireless and cables are PHYsical components. They deal with transferring bits directly; there is a specific process for each medium.

The networking stack itself is made of layers (PHY, LINK, NET, TRANSPORT, APPLICATION in the TCP/IP model). Each layer is responsible for managing its own view of a connection.

In general, the flow looks something like the following (very abstracted) model:

Application      -> Send Data
  Transport      -> Encapsulate data; possibly ensure reliability over link
    Internet     -> Encapsulate data; provide addressing over network
      Link       -> Encapsulate data; provide reliable connection to _peer_
        Physical -> transfer bits over the medium

The remote side reverses this process until an application receives the originally send data. Retransmits may occur at any layer. Not all layers are always used.

Ultimately, the physical portion of the network simply deals with getting bits from one device to another; the logic of requests, reliability, and data is managed at a much higher layer.

i know about theese layers here you gave me an explaination from a software view but no i want to know how this physically happens if we send many files through ethernet (rj45) and browse the web at same time how the cable and router could manage theese requests and data in the same time without a delay, missing any part or confusion ???

From the physical point of view it is mostly just the following loop:

while true:
   if not output_queue.empty ():
      extract bits to send from output_queue
      send bits

The device itself doesn't care that the bits represent web content, video, an ftp transfer, or an SSH session. The logic for all of that resides at the upper layers. At some point, data frames are placed in a queue and the device transmits the data; there isn't any magic to it.

When multiple applications try to send/receive data at the same time over the same network link/connection, the network driver will mostly queue them in FIFO (First In, First Out) order. The network hardware will send/receive until it has reached its performance limit, which with modern hardware ports, is as much as 1Gbps (1 gigabit per sercond == 128 mega bytes per second). WiFi is slower, and most internet connections are even more so.

Anyway, there are delays. It is just that they are so short most of the time, you will never notice them. That's why I can stream audio over my internet connection while viewing a YouTube video at the same time, and not notice that there is buffering going on, unless my wife decides to upload another video to YouTube or Facebook at the same time... :-)

need more details thnx guys for replies

Here are the details of an Intel Ethernet controller. It has state machine diagrams, descriptions of functionality and the details of how one of these cards operates.