Table of contents
1. Production of network cable
1.1. Standards of network cables
2. Introduction to OSI seven-layer model, hubs and switches
3.2. Introduction to commonly used functions
3. How to prevent network corruption?
That’s it for today, I hope it helps you! ! !
1. Production of network cable
Materials: network cable, network cable clamps, crystal head, network cable tester or router (optional)
Network cable: Network cable pliers:
Crystal head: Network line tester:
router:
Network pliers :
1.1. Standards of network cables
T568A standard (crossover cable) :
- Applicable link occasions: computer - computer, switch - switch, hub - hub
- Wiring sequence: white-green, green, white-orange, blue, white-blue, orange, white-brown, brown
T568B standard (straight line) :
- Applicable link occasions : computer -ADSL modem, ADSL modem -ADSL router, computer -ADSL router, computer - hub or switch
- Wiring sequence: white-orange, orange, white-green, blue, white-blue, green, white-brown, brown
1.2.How to make crystal head
- Use network cable pliers to cut the network cable
- Peel off outer cover
- Arrange network cables in the order of T568B
- Insert the crystal head in order (copper piece facing up)
- Press the crystal head and press the metal piece into it
- test
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②
③
④
⑤
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2. Introduction to OSI seven-layer model, hubs and switches
The OSI seven-layer model (Open System Interconnect), the open system interconnection reference model, was proposed by the ISO ( International Organization for Standardization) as a standard system for interconnection between computers or communication systems.
The OSI seven-layer model can be divided into seven layers from top to bottom: each layer completes specific functions, provides services for the upper layer, and uses the services provided by the lower layer.
7. Application layer (Application): Provides network services for user applications
6. Presentation layer (Presentation): Represents information as a data stream in a certain form and format
5. Session layer (Session): Responsible for sessions between communication hosts Establish, manage and tear down, coordinate the sessions between the communicating parties
4. Transport layer (Transport): Responsible for the end-to-end connection between communication hosts
3. Network layer (Network): Responsible for sending packets from the source machine to the destination machine, including addressing and Optimal path selection, etc.
2. Data Link layer (Data Link): Provide reliable frame transmission, implement error control, flow control, etc.
1. Physical layer (Physical): Provide transparent bit stream (01 stream) transmission
- Physical layer :
To solve the problem of how to communicate between two pieces of hardware, common physical media include optical fibers, cables, repeaters, etc. It mainly defines physical equipment standards, such as network cable interface types, optical fiber interface types, transmission rates of various transmission media, etc.
Its main function is to transmit bit streams (that is, converting 1 and 0 into current strength for transmission, and then converting into 1 and 0 after reaching the destination, which is what we often call digital-to-analog conversion and analog-to-digital conversion). The data at this level are called bits.
- data link layer:
In computer networks, physical links are unreliable due to the existence of various interferences. The main function of this layer is to turn the error-free physical channel into an error-free data link that can reliably transmit data frames through various control protocols.
Its specific job is to receive data in the form of bit streams from the physical layer, encapsulate them into frames, and transmit them to the upper layer; similarly, it also disassembles data frames from the upper layer into data in the form of bit streams and forwards them to the physical layer. The data at this level is called a frame.
- Network layer:
If there are multiple computers in a computer network, how do you find the one to which you want to send? How to choose a path if there are multiple nodes in the middle? This is what routing does.
The main task of this layer is to use the routing algorithm to select the most appropriate path for the message (the data unit of this layer, packaged from the data of the previous layer) through the communication subnet. What this layer defines is the IP address, which is addressed through the IP address, so the IP protocol is produced.
- Transport layer:
When sending a large amount of data, packet loss is likely to occur, and the other computer has to tell whether all packets have been received completely. If it is missing, tell which packets were lost, and then send them again until all are received.
Simply put, the main function of the transport layer is to monitor the quality of data transmission services and ensure the correct transmission of messages.
- Session layer:
Although it has been possible to send the correct encapsulated information to the correct computer. But it is impossible for us to call the transport layer protocol to package every time, and then call the IP protocol to find routing, so we need to establish a function to automatically send and receive packets and automatically address. So the session layer appears: its role is to establish and manage communication between applications.
- Presentation layer:
The presentation layer is responsible for data format conversion, converting information processed by the application into a format suitable for network transmission, or converting data from the next layer into a format that the upper layer can process.
- Application layer:
The application layer is the interface between computer users, various applications and the network. Its function is to directly provide services to users and complete various tasks that users want to complete on the network. Front-end students are definitely the most familiar with the application layer.
- Hub: (Hub) refers to a device that connects multiple Ethernet twisted pairs or optical fibers together under the same physical medium. Happens at the physical layer.
- Switch: (Switch) is a network device used for forwarding electrical (optical) signals. It can provide an exclusive electrical signal path for any two network nodes connected to the switch, and send the transmitted information to the corresponding route that meets the requirements. Occurs at the data link layer.
Hub:
Function: A hub is a simple network device mainly used to connect multiple computers and share network communication media. It broadcasts received packets to all connected devices, regardless of whether they are the target device or not.
How it works: A hub is a shared-medium device, which means that all devices connected to the hub share the same communication channel. When a device sends data, the hub broadcasts the packet to all ports, and all connected devices receive the packet. This can lead to network congestion and conflicts.
Collision Domain: Due to the nature of the shared medium, hubs create a collision domain. When two or more devices try to send data on the network at the same time, collisions can occur, resulting in packet loss. To resolve collisions, the hub uses the CSMA/CD (Carrier Sense Multiple Access with Collision Detection) protocol.
Speed: Hubs often limit the speed of a network due to the effects of collisions, and are rarely used in modern networks.
Switch:
Function: A switch is a smarter network device used to connect multiple devices and establish direct, point-to-point connections between them. It learns the MAC addresses of connected devices on the network and uses these addresses to decide which specific device to send packets to.
Working method: The switch maintains a device address list by learning the MAC address table. When a device sends a packet, the switch looks up the address of the destination device and sends the packet only to that device, rather than broadcasting to all devices. This improves network performance and reduces conflicts.
Collision domain: The switch logically creates a separate collision domain for each port, so each device can send and receive data independently, avoiding collision problems.
Speed: Because the switch uses point-to-point connections, it can support higher network speeds, often running at gigabit speeds or higher.
Switches are more advanced and efficient than hubs. In modern networks, hubs have been largely replaced by switches because switches are better able to handle data traffic and improve network performance and reliability.
3. Router configuration
- Router: ( Router) is a device that connects various local area networks and wide area networks in the Internet. The routing table is recorded in the router. It will automatically select and set the route according to the channel conditions, and send signals in order using the best path. Happens at the network layer.
3.1.Use
Computer debugging: After connecting the network cable, set the IP address to automatically obtain.
Mobile phone debugging: The default WIFI name needs to be connected. The default name is indicated on the label on the back, and the password is empty.
Configure via computer web page:
When you log in to the router for the first time or after Reset, the interface will automatically display the setup wizard page. According to the setup wizard, you can access the Internet and set up wireless for use by mobile devices.
1. Open the browser and enter [tplogin.cn] to enter the router’s login page.
2. Fill in the administrator password you want to set in the Set Password box (6 to 32 characters, preferably a combination of numbers, letters, and symbols), enter it again in the Confirm Password box, and click [OK].
hint:
If you forget the administrator password, please click Forgot Password on the login page and follow the prompts to restore the router to factory settings. Once you restore your router to factory settings,
You need to reconfigure the router to access the Internet.
3.2. Introduction to commonly used functions
At present, home routers have very rich functions. Here are some practical functions for you:
1. How to manage the router
Currently, the common management methods are browser web page management and mobile APP management. Generally speaking, browser web management pages have more complete functions, but are relatively troublesome. This method is recommended for first-time configuration.
After connecting your mobile phone or computer (wired) to the router WiFi, open the browser and enter 192.168.0.1 (TP-LINK routing) in the address bar. The login page will pop up. You need to set a login password for the first time.
APP management download corresponds to APP operation, which is very simple and will not be introduced here.
2. Parental control function
This function of the router is great news for families with children. You can set the time period when children can access the Internet to prevent them from being addicted to the Internet during breaks. In addition, you can also set up a black and white list to filter some harmful information websites. At the same time, for parents, you can also view Provide active guidance and management of children's Internet records.
3. How to prevent network corruption?
If you find that your home network is much slower than usual, you may want to pay attention to whether someone else has used the network. Enter the device list. If you find a device you don't recognize, you can click one click to disable it so that he can no longer use the network.
In addition, if an acquaintance asks for the WiFi password, but due to limited home bandwidth, if others use it too much, it will affect your own network, so you can limit the speed during peak network usage periods.
4. QOS function
If there are many devices at home and limited bandwidth, how to ensure the bandwidth needs of high-priority devices during peak Internet access periods?
In behavior management, you can limit the speed of some unimportant devices at specific times to ensure that high-priority devices have priority in accessing the Internet.
5. Guest network
Whenever a guest comes to ask you for your WiFi password, it is a very troublesome thing. It not only exposes your home WiFi password, but also makes it troublesome for guests to access the Internet. The best solution is to enable the guest network and set it to not encrypt. , guests can directly connect as long as they find the corresponding WiFi name. At the same time, they can also limit the speed of the guest network, giving priority to the host network.
6. USB function
Some high-end routers have USB ports that can be used to connect external hard drives or NAS as home LAN storage devices.
Let me provide you with a website to learn from
TP-LINK TL-WDR5660 Gigabit Router Detailed Configuration Instructions
4. Mind map
