Switch
It is a multi-port device (slots 5 port - 8 port - 16 port - 24 port - 48 port) that connects devices to each other in one LAN network through cables connected to the switch and devices. (IP knows - we will talk in detail in upcoming lessons)
The switches have different ports (the slots in the switch), including 48 ports, including 24 ports - 16 ports - 8 ports - 5 ports. And every port (slot) in the switch comes out of it a cable to one device only (one port cannot be shared by more than one device) and the switch slot has RJ45 installed in it, and as the cables also had speeds, the switch slots also have speeds measured by the concept of ETHERNET (a protocol related to the network Internal LAN, which is responsible for communication between devices in the internal network.
Types of switches in terms of speed: Each switch has slots with different speeds, including:
Ethernet: It is a switch with a speed of 10 megabits per second (10 mbps).
Fast Ethernet: Speed 100 Mbps.
Giga Ethernet: Speed 1000 Mbps.
All these switches are similar and cannot be distinguished easily except by reading what is written on the slot, on the sticker behind the switch, or in the catalog that comes with the switch when it is purchased, through which it is possible to know the type of switch and the speed of the different slots.
Likewise, any net cable can be installed in the switch, but it is better to take into account the ratio and proportionality between the cable and the switch, for example
Ethernet switch + cable cat 5 cable.
Fast Ethernet switch + cable cat 5 e cable.
Giga Ethernet switch + cable cat 6 cable.
Why do we do that... As we said, we can install any cable of any kind in any switch and it works efficiently, but it is better to take into account the cable speeds in order to match the speed of the switch slots in order for the service to be better, better, and faster, because for example, if we connect a cable cat 5 cable with The switch speed of its Giga Ethernet slots will certainly work, but not at the required level, because the cable speed will be less than the speed of the switch slots, and therefore we will not benefit from both as required (the data transfer speed will be slow because the cable speed is higher than the speed of the switch slot) and also If we connect a cat 6 cable with an Ethernet switch, the service will also work, but not correctly, because the cable speed will be higher than the speed of the switch slot (the data transmission speed will be weak because the cable speed is higher than the speed of the switch slot) and so on.. and the switches differ Its price depends on the speed and also the number of slots, i.e. the higher the speed of the slots and their number is large, the higher the price of the switch in the market.
How the switch works
It works in a smart way to transfer data by creating a table inside it consisting of two columns:
Destination
Source
5
1
Example: Switch + 5 computers
Device No. 1 (the source) sent data (movie .. song .. file ... email) to device No. 5 (the target), the switch sends it the first time to all devices (pc1, pc2, pc3, ps4, pc5) And when Device No. 5 receives the data and does not return it again to the switch, the switch knows that Device No. 5 is the desired target, so it stores that in its schedule so that it does not repeat the same mistake in sending data to all devices again.
Flame Hub
It is a device similar to a switch (it cannot be distinguished from a switch except by reading what is written on it) and it was used in the past and linked devices together in one network, but it used to deal with data as if it were electrical waves and not deal with it as if it were data, and it did not understand anything and it was all Simplicity is like the electricity subscriber who connects electricity to the video, television and cassette together, he does not understand anything (he does not know the IP) and sends the data using the Broadcast system, meaning that when a member of the network wants to send data of any size, he sends it to all devices and the owner of the data is the one who accepts it Just. As for the rest of the devices to which the data is sent, they return them back to the flame, which used to cause network problems and slowdowns.
(The word “Broadcast” as it means “broadcasting” whether it is radio broadcasting, television broadcasting, etc.)
Example: radio broadcasting. As the radio broadcasts the content via the radio, but it does not require that every user access or hear the radio, and it does not require that every radio device be compatible with the radio frequency, and it does not require every listener to hear the broadcast.
If Device No. 1 (PC 1) sent a message (it could be an email, a song, a movie, etc.) to Device No. 5 (PC 5), the hub was receiving the message from Device No. 1 instead of sending it directly to Device No. 5 It was sending it to all devices (PC 1, PC2, PC3, PC4, PC5) and device number 5 will receive the message addressed to it and will not return it to the hub, while the rest of the devices will return the message to the hub again (not addressed to it ) and the hub then receives these messages from the devices
(PC2, PC3, PC4) and send it again to Device No. 1 (PC1), which sends it again to the hub with the aim of delivering it to Device No. 5, PC5 (the hub does not know that Device No. 5 has received the message) and so this process continues a lot in the network It passes through devices, flame holes, and cables, which ultimately leads to suffocation and slowdown of the network, and thus causes the so-called LOOP, or sudden death of the network at the end.
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