Đăng bởi admin 01/06/2016 0 Bình luận NEWS,

Currently, wireless networks are still the backbone of the Internet world. A billionaire arms procurement can play hundreds dominant expensive wifi router to cover the entire campus wide villa his few hectares, or some cities can conduct advanced wifi coverage across the entire urban area , but in the end to connect to the world, which still have to have some equipment connected to the conductor of the network provider (ISP), our technology has not reached the threshold can make the system global wireless network. So whether you are designing a home network to all devices are using wireless signals, the wireless networking knowledge is greatly needed. Moreover, some sectors of the wireless network we are about to find out this time, but may be difficult to understand than the knowledge of the network address before slightly but are essential points need to know if you want to improve the quality of the connection, fix or detect dangerous.


ISP wiring is used to transmit the signal to the door you can not fixed, depending on your type of network subscribers they will give different types of wire. With the case of heading DSL network (the most popular is ADSL & SDSL) is the telephone wire, cable television taken by the majority would be a coaxial cable, fiber-optic network also uses optical fiber course. Generally, when registration successful network services, maintenance and cable wiring for this is the responsibility of the ISP. You just need to know which type to purchase equipment appropriate signal converters (like the absence of conversion equipment used by the ISP) and so missed a good day off also know the road network runs out the door check right line to his house, lest the Internet using cable that saw off the telephone line to the switchboard call complaining.

Within the scope of the family in particular and small LANs in general, the most popular today is still twisted Ethernet cables (Twisted Pair Cable). In essence, it does not distinguish this kind ... does not matter, but if you really want to do the work in-house network management, optimal quality and speed of connection, it should also give a bit of effort to find out.

First to distinguish the connection of twisted RJ145 RJ11 Ethernet and head of the phone lines are often used to plug into the port on the DSL modem. Smaller and less wire RJ11 more.

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Regarding the classification of Ethernet twisted pair cable, or wireless LAN is called rustic, one of the following methods:

Unshielded Twisted Pair (UTP) vs Shielded Twisted Pair (STP)

Ethernet twisted pair cable made of copper wire 8, are twisted together in pairs to form 4 pairs. Type jacketed shielded (STP) in addition to the outermost layer of rubber and outside each individual fiber, also added a layer on each pair shielded wires. And as the name implies, do not wrap the cable (UTP) of course is no more of this protective layer. Thanks to the protective layer, STP predominant in areas such as anti-jamming capability and environmental impact, more stable signal transmission over longer distances. But also so that STP is more expensive, heavier, less flexible, more rare, hard to find buyers hon..v.v ..

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STP cable.

Households typically spend UTP cords to plug in and thrown on the floor rolling surf sitting, at best, then tucked into a corner (some cases will be affected by the quality of UTP connections are vulnerable to signal interference if to need the kind of electrical signal wires). But also do not be so subjective that, if at any time you need to set up a home network system requires putting out or transmitted by wire distance a bit far, or wiring near the interference source such as electrical equipment , then knowledge of STP goals will save you a saw.

Core characteristics (solid) or Core braided (stranded)

This is a way to distinguish the structure of the copper wires of the cable. Core copper wire characteristics, such as the name describes, only a monolithic fiber, and fiber core wire braided so many children this creation. Generally, the core wire characteristics but helps communication on longer distances but less flexible and more prone to damage if they are folded too many times. Yet thanks to cheaper & easier to manipulate than the cable press is still more common type on the market, so you should also note that should not "suppress" his house wired network so if it's not obvious that wire braided core.

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Special core.

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Braided core.

Straight cable (Straight-through cable) and crossover cable (crossover cable)

Do not think about every purchase Ethernet cords, fibers which connect the RJ45 early transfer in accordance with the corresponding color is used by all the circumstances. Depending on how the fiber connection from 1> 8 at 2 top cable Ethernet cable which will serve different functions. Remember how connected functionality of 2 cables is also very simple, the device is divided into 2 groups in the house:
Group 1: Router, PC, Server, lap ...
Group 2: Switch, Hub and other network devices

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These devices are connected to each group using a crossover cable, straight cable, use different types, that's all. However it should be noted some problems with the modem notes. Inherently the router, the modem not switch or hub or anything, it originally created to serve a separate job (we'll mention later). But demand for network management in households where there is need to specialize too do, so that manufacturers - particularly Chinese firms can keep everything straight integrated hands on it for convenient functions for users affordable, routing switches and DHCP NAT firewall is enough. Most router acts as a simple, but some sort of cheap old actually functioning as an ... switch to add more ports to dread, so that we have to watch out a bit when the cable plug, preferably with a cable modem included.
The same Ethernet cables, you can turn it into a straight cable or crossover cable connection, depending on how the fibers are as follows:

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Or if afraid to touch the cable, the simplest way is to store each piece of short cable to buy and ask them to press for each type 1 2 fibers. You see how remains confusing afterall? Rest assured that the majority of current devices Auto-MIDX functions help identify cables & connectivity types to automatically change accordingly, meaning you prefer cross straight plug whatever. Part of this knowledge is only for those who are interested in learning to optimize network quality temporary or no funding to upgrade to devices that support Auto-MIDX.

Distinguish cable pace

If ever find in all kinds of speed through the Ethernet cable out there, you will find many places talking to 5 6 or 7 standard take speed for Ethernet twisted pair cable. Generally this is the theoretical level, some with no effect on end users like us. Currently we only need to know:

Cat 5: The most basic kind, providing 10 Mbps or 100 Mbps.
Cat 5e: Upgrade from Category 5 to support speeds up to 1000 Mbps.
Cat 6: Speeds up to 10Gbs !!!!

It is so split, even after Cat 6 also includes 6A, but you use speed ADSL network around several hundred KBps? You never or rarely have to copy / stream several hundred GB HD movie in the LAN? Not your home wifi router supports WiFi N standard is the standard let alone the latest AC? Feel clung Cat 5 wiring for serenity. Even if they do make quite a few NAS indoor workstations, upgrade to Cat 5e is also the optimal choice then.

Power over Ethernet (PoE)

Scattered a little more, we also have self-powered Ethernet connection. Power over Ethernet technology uses existing electrical capacity of 2 redundant pair of 4 pairs of twisted copper (essentially spend two pairs are used to transmit data) to transmit power to the device. Dimensional energy transfer can be changed according to the needs, creates a lot of potential uses. For example, you can set the wifi router anywhere without a power plug, as long as it's connected to the modem - very convenient to reduce the number of wires in the room. Or when bringing a laptop to a public office has had to deploy PoE, you will not need to bring more flexibility of the glass adapter, just plug in the network cable into (although the energy levels just enough to be able to use at medium). PoE biggest problem is that all participating devices must support this technology. So when you want to test in the house, you have to carefully check the information of your device.

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Bulk Charging the device with a single socket.

Note: Indeed, in the LAN, and Ethernet cables including optical, copper .. Dedicated not only twisted. But the price of network equipment supporting the cables are often not "affordable" for much.

Network equipment

After the address, roads were also constructed. Now it is time we learn to the post office, who led the way for your data on the network.


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Honestly, was supposed to be introduced in the modem end of the list, after you read has a better understanding of the different types of equipment, but due to its popularity, we decided to introduce first. Basically, modems (modulator and demodulator acronym) just switch devices ranging from analog signal (analog) phone networks into digital form (digital) for electronic devices of our understanding and treatment be reasonable. This applies to both mobile networks and wireless, that's why if you pay attention you will find many ways to use the sales page says "3G modem", rather than a 3G USB as a humble way. Modem born basically to serve this purpose. But in the long run due to the strong development of the hardware and the need to use personal networks in a narrow range, the manufacturer has decided to undertake this device most of the roles needed for a home network small as NAT, DHCP, firewall, router or layer 3 switch, sometimes as always both wireless Access Point. Listen, it is very convenient, but remember that they only specialized high performance new job. If you try to connect 4 computers and a few phones, tablet into a modem concurrently all the functions mentioned above, you will feel the stress of it almost immediately. Even linksys expensive models also just enough to serve as a small business households cafe.

Network Interface Card (NIC)

Concept Network Interface (network interface) are the producers explained in many different ways depending on the circumstances, but to fully synthesize we can say in a somewhat confusing way that this is a point communication between a computing device with a device or other network systems. The two devices will communicate with each other via their 2 network interface. This means that if you previously heard network interface is a hardware component is completely insufficient. Those who have installed Virtual Box or VMware virtual machine would have found a symbolic name of the form "VMware Network Adapter 2" icon next to the name as "Local Area Network" or "Wireless Adapter Area". All these points are connected, but "VMware Network Adapter 2" is a software component by the VMware program created to help you connect to the virtual machine. And "Local Area Network" or "Wireless Adapter Area" is the symbol representing a hardware component in your PC, but the card is the network (Network Interface card- NIC) for your computer to communicate with followers wired or wireless signal to the outside world. If there was a beautiful day on your nerves because network wires heap womanizing, manipulation should do is simply check empty slot on the motherboard, go buy a wireless NIC appropriate plugged in, then install driver PC to the wireless network is delectable. The use of NIC is. If not grasp the concept of network interface, you're sure to encounter many difficulties when curious to advanced configurations on the PC, network devices or thin clients. Also remember always, each network interface based on whether hardware or software may also use an IP.

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Here we pause for a moment to recall the MAC address, physical address as mentioned in the previous article through is unique to each participating device, is a next solution to serve the specified IP equipment list and find a way. Actually, to be more precise, this is the address that the manufacturers began to die on the NIC, which means that for example your laptop has 2 NICs (network 1 for wired and wireless 1) there will be 2 MAC address . Connect your laptop to the wireless network, it will be the wireless networking devices that recognize you by your wireless NIC MAC, while the wires connected to the network shall be recognized by the other NIC MAC. Mobile devices, tablets can of course just as we do not have one MAC tucked away that many, who would plug the network cable into the tablet ever?

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As well as a unique identifier role - similar to the role of the human fingerprint should in most cases, we do not need and should not change the MAC. The method is carried out constant heavy intervention edit ROM (read-only memory - read-only memory) NIC works only on some models, and requires a lot of knowledge. And the usual intervention methods online is a "fool" to the operating system and other devices can not read MAC truth - instead only see false addresses generated by the tool. The tools that you download to do this is often not safe, should not venture without actually needed. Instead, if you have legitimate needs that should learn to use the method to bring more legitimacy as MAC Cloning function on some modem / router Linksys and TP-link.

Note: if you have a good grasp of the NIC, the memory using the straight-crossover cable is also very simple: the connection between the two devices to communicate with each other NIC, use a crossover cable (router with multiple NICs, each NIC era communication interface with a subnet), from one device to another device NIC NIC but no role as transshipment hub, switch, use a straight cable.

Repeater, Hub and Switch

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As we all know, the electrical signals transmitted over wires deteriorate gradually with distance. The most primitive form of the Repeater is a device with two ports, one port to plug signal line (weakened) in, 1 head to plug the transmitter (already repeater energize) go forward, thanks TV signals that go further without the use of wires "genuine" as listed above.

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Hub is simply a multiport repeater, input on port 1 will be pushed out on all remaining ports, that's all. But many sources port means of sending and receiving various data, which is the only repeater hub just-energizing equipment for electrical signals, few mechanisms to understand and manage its heap signal processor . So when multiple computers in the same network to send signals, likely conflict data (packet collision), sometimes also causing reduction hub connection quality rather than increase. Take the example for you to read easily understood, like a repeater placed between pipes pumps water from the tank to help push water tank A to B faster. But hub? A pump is connected to several reservoirs A, B, C, D; A flow of water from the tank to the pump is accelerated push for the pool B, C and D. But if at the same time the water in the pool B and C are flow pumps? Sure collision! The mechanism of the anti-collision packet hub very limited, we also bought the day before temporarily to replace the switch by using cheaper hubs, switches are now dirt cheap price, it almost was pleasantly hub, Concerts affordable only repeater is there where used.
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Switch Dlink 8 port popular.

If you look through, the switch is the same hubs, just a hyperintense devices, including multiple ports to connect multiple computers together to create a subnet. The most important difference is the smart switch mechanism to read a piece of content data sent, thus helping to perform two operations:

A processor to process the signal on the wire do not conflict. If you want to learn a bit more communicative approach in which each support only one of the line to send data (if not conflicting) as called half-duplex hub; also switches and other network equipment types are active today with full-duplex mechanism, which is allowed to send and receive data at the same time on the same connection. Without full-duplex, or you have to wait all day to turn into facebook, or to accept comments submitted stories will be spoiled like "choowj lâ qa".

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Two is the only transfer the data to the necessary destination instead of pushing out all ports. Every turn the switch on, it will be conducted to find out the MAC of the devices connected to each port of it to know which port device connected to the MAC. When a PC on the LAN wants to send data, it must address two target: IP and MAC. The IP address is the public IP of course of recipients, as we have said in the previous section. But the destination MAC? If the recipient is the LAN machines, of course, the destination MAC MAC machine (fully verbalize the NIC MAC that is used to connect the machine to switch, lest you later have misread the MAC's wifi card). If the recipient does not lie with the LAN, the PC will set the destination MAC is the default gateway MAC - usually the router, modem - so thanks to that router conduct "pathfinder" to the Internet based on IP address. A switch will essentially based on the destination MAC to push out the right signal port is off duty.

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We need to understand the mechanisms underlying the above switches to promptly detect a "poke" popular today: ARP poisoning. When the signal passes only through such a fundamental switch, the machine on the LAN will have the feeling of being in touch with each other directly and not through any intermediate device. ARP mechanism by which the device is used to ask the same LAN MAC with their machines so simple and easy, just the kind of situation he has bragging neighbor that his Harvard is the neighbors you have believed wrong even then. If you're using Windows, you can turn up typing cmd arp -a to see if the IP-MAC table information of your machine. The simplest form of harassment is the culprit of the IP address MAC variable (the most common default gateway) in the table that you just look into his MAC, PC and switch so innocent any transfer your data into it . Is your Internet connection now regarded as lost and that perpetrators are euphoric snooped data you send out or simply taking advantage of the time nobody got into network bandwidth paintings ... studying. The more dangerous variants and how we are going to prevention for the security posts, and current if the network is shared with many people "do not trust" - you just know that when the network operation normal should seek to save the default gateway MAC (or the network as possible); if fails, the second reference also to see you are being a bad play.

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Arp Table.

Generally the basic types of switches (unmanaged) fully automatic operation, direct access to machinery we do not even know that there is another intermediate device ... people. The switch does not communicate directly with a PC, a laptop should not have NIC, which is also its own IP or MAC no. So in addition to note about the above MAC and properly selecting the type of wire (if the switch does not have Auto-MIDX), we do not need to remember what the configuration information for the switch even more complex. Just connect the device to the switch in the house, at the first notes that much is 3 "uncle" - corresponds to the division of equipment into 3 subnets, each switch remember to set aside a default gateway, a gateway to the Internet (router / modem in the home) is that you're done with the switch cluster.

- Note 1: Bridge is also active devices based on the same MAC address as the switch, but there is little more ports. While the switch serves to connect the terminal device (laptops, PCs, servers) together to form the bridge subnets mainly serve to connect two subnets together. With consumer demand, we use always the basic router to make this work helps to simplify matters.

- Note 2: The type of switch operating mechanisms usually involved IP Layer 3 switches, mainly used for enterprise environments. If family members need to install complex systems that have little involvement in IP routing using the router, then use more still.

Bonus: Those who are interested in better understanding the basic mechanisms of the switch switches, can visit this link for more.


If said wired network is the backbone of the Internet, the router is the most important vertebrae on it. I address to each computer, there is the road connecting wires between the machine, so have done? Data sent from a computer A to computer B, is similar to a letter sent from his home to her house a B, if no help, how they move themselves to find their way to where? Switch devices connected just a small amount of machine to create subnets, only know the destination MAC see among the computer directly connected to it (or at best a 1 2 baby switch, bridge parts) are not then ejected corresponding port, and not as it had pushed the mess all ports (flooding), absolutely no way reasonable to apply it to a wide area network with thousands, millions of computers.

This is when we need to router - post offices. Information stored on the router will route to the device in the network based on IP address (done with temporary switch as we have done with the MAC), the information may be the way of complicated forms or LAN the WAN to the data pass through the router, it will know which direction to go any direction that data. If a router does not know the direction of travel information directly to the destination, it should at least know the directions to find the router data do .... to ask for directions. Similarly when you go through a postal Hanoi to America, although unknown paths in the US but will be able Hanoi postal mail forwarding it to the international postal organizations, these organizations help transferred to the US post office and the post office will be responsible for delivering mail to a particular address that. Systems routers connected together will ensure data is always taken as long as the target destination that exists (and not blocked).

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Within the scope of the family, most cases we only need one modem cum router, at best, it can add 1 wifi router, the LAN-recognize WAN address to determine the way so often takes place automatically or by the ISPs do san ktv PCs, laptops will also know which set the default gateway is your router. Moreover to learn the routing mechanism (pathfinder), you need to have a bit more understanding of the structure of the IP address, subnet, netmask and wildcard mask, so we will not rush to dig deep these mechanisms is here. To serve home networking, first ensure that you understand the problem of connectivity as follows:

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This is the image of a router "mainstream", that is not an integrated modem router functions. As we saw above that there is a WAN port, NIC charge represents the connection to the Internet, this is your public IP NIC bearing, stood out representatives to help you communicate with the world. Four LAN port is connected directly to a PC, laptop or switch connected to the corresponding network management, and on the majority of today, the four-port routers are part of the general in charge of an Ethernet NIC to connect to the machines in LAN. Ie how much you want to use the switch is used, the connections How connected, even how naughty subnet is against, all the computers in your network will share the default gateway is the LAN NIC charge it (With default IP is common place). Total your router has 2 NICs and 2 IP, all connected to the Internet will have to go through 2 him this, his first of two that had problems, though there are 4 LAN ports ... you will have to replace the new router as usual because not easily removable NICs on the residential router is.


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