AP is the HUB in the traditional wired network, and it is also the most commonly used device when building a small wireless LAN. The AP is equivalent to a bridge connecting the wired network and the wireless network. Its main function is to connect the wireless network clients together, and then connect the wireless network to the Ethernet to achieve the purpose of wireless coverage of the network.
AP is also divided into "thin" and "fat"?
Thin AP (FITAP):
Also known as wireless bridges, wireless gateways, also known as "thin" APs. The transmission mechanism of this wireless device is equivalent to a hub in a wired network, and continuously receives and transmits data in a wireless local area network; any PC or mobile terminal equipped with a wireless network card can use a wired local area network or even a wide area network through an AP. Resources.
In theory, when a wireless AP is added to the network, the network coverage diameter can be expanded exponentially; and more network devices can be accommodated in the network. Each wireless AP basically has an Ethernet interface for wireless and wired connections.
Popular understanding:
Thin AP: It cannot be configured by itself, and requires a dedicated device (wireless controller) for centralized control management configuration.
The "controller + thin AP + router architecture" is generally used for wireless network coverage, because when the number of APs is large, the configuration is managed only by the controller, which simplifies a large workload;
Fat AP (FATAP)
The so-called fat AP in the industry is also known as a wireless router. Wireless routers are different from pure APs. In addition to wireless access, they generally have two interfaces, WAN and LAN. They support address translation (NAT), support for DHCP server, DNS and MAC address cloning, and VPN access, firewall, etc. Features.
Second, what is ACAC
The Wireless Access Point Controller is a network device used to centrally control the controllable wireless APs in the LAN. It is the core of a wireless network and is responsible for managing all wireless APs in the wireless network. The management of the AP includes: Send configuration, modify related configuration parameters, RF intelligent management, access security control, etc. (All current ACs and APs in the market are the same
The ability of the vendors to manage each Other)
What is POE power supply
POE (PowerOver Ethernet) POE is also known as a LAN-based power system (PoL, Powerover LAN) or Active Ethernet, sometimes referred to as Power over Ethernet, and refers to existing Ethernet Cats. .5 The cabling infrastructure can provide DC for such devices while transmitting data signals for some IP-based terminals (such as IP phones, WLAN access points, APs, etc.) without any changes. Power supply technology. POE technology can ensure the normal operation of existing networks while minimizing costs while ensuring the security of existing structured cabling.
What is a POE switch
In addition to providing the transmission function of a common switch, a POE switch can also provide power supply to the other end of the network cable. Power supply + data transmission integration, no need to add power supply module or POE power supply module to supply power to the equipment, a Cat.6 line to complete all work.
The POE switch is a POE switch designed to reduce network congestion, support long-distance network power, and implement data conversion. It has both basic functions of the switch and POE power supply. Each POE power supply port can provide up to 15.4W of power, and can supply power to wireless APs, IP cameras, network remote devices, etc. Plug and play, providing a low cost and high performance network solution. The transmission distance can reach 100m, (the non-standard Cat.5 network cable is recommended to be controlled within 70 meters). It is easy to install and plug and play. Ideal for wireless coverage, security monitoring and other environments.
The line-up data feet used by the standard POE power supply (End-Span) are 1/2 (+), 3/6 (-), and most of these types of switches are H3C/CISCO/Huawei.
Non-standard POE power supply (Mid-Span) line sequence idle feet: 4/5 (+), 7/8 (-) This type of POE switch is more than China, using DC.
POE power supply "standard" and "non-standard" differences
• Standard poe: According to the IEEE802.3af/at specification, it is necessary to first detect the 25K characteristic resistance of the receiving end, perform handshake, and successfully transmit the power before it is powered; otherwise, only data (data).
• Example: Plug the POE power supply into the computer network card, it will not burn the computer network card and only can access the Internet because the data can pass.
• Non-standard POE: Also called strong supply type, the AC power is supplied when the power is on; the power terminal is not detected first, and the handshake is not performed, and the power is directly supplied by 48V or 54V.
• Example: Plug the POE power supply into the computer network card to access the Internet normally, but do not negotiate direct power supply 48 or 54V, which may burn the device.
The market is roughly divided into several output voltages (DC) such as 48V, 24V and 12V.
What is Portal authentication?
Portal authentication is an authentication method. The English translation of Portal is the meaning of entry or entry. Portal authentication is a verification method when entering. Some people call it web authentication. It is an authentication method for Internet access. The underlying implementation of DNS hijacking, the access page jumps into the authentication interface, based on a variety of authentication methods. Such as WeChat, Weibo, QQ, mobile phones, coupons, etc. It is used to realize the embedding of graphic, video and other advertisements before online authentication.
Many users may have misunderstood the concept of roaming and seamless roaming. Roaming and seamless roaming are two concepts. Please understand that I will explain separately here.
Roaming concept
"Roaming concept" When there are multiple APs in the network environment, and their micro-units overlap with each other, the wireless users can move within the entire WLAN coverage area, and the wireless network card can automatically discover the AP with the strongest signal strength nearby and pass the This AP sends and receives data and maintains an uninterrupted network connection. This is called wireless roaming.
Distribution requirements:
a, all APs use the same SSID, (note that SSID is case sensitive)
b. Must use the same WEP or WPA encryption method and set the same password. If it is an open network, you can ignore this one.
c. All wireless APs need to be in a single LAN, which refers to the IP address of the same network segment.
d, the coverage between APs needs to be relatively overlapping, that is, the AP radius is 30 meters, then the distance between the two APs is preferably controlled within 50 meters. (The overlap range is around 20%~30%)
e. The channel selection between adjacent APs is manual, and different or even non-adjacent channels are used as far as possible. The IEEE802.11g standard only supports three non-overlapping transport channel channels, and only channels 1, 6, 11 or 13 are non-conflicting. ,
Note: In the case of 802.11b/g, the available channels are overlapped and interleaved in frequency, resulting in only three non-overlapping channels in the service area covered by the network. As a result, users in this service area can only share the data bandwidth of these three channels. These three channels are also subject to interference from other radio sources because the 802.11b/g WLAN standard uses the most commonly used 2.4 GHz radio band. This band is also used in a variety of applications, such as Bluetooth wireless connectivity, cell phones and even microwave ovens. The interference generated by these applications in this band may further limit the available bandwidth of WLAN users.
Roaming notes:
According to personal experience, if high-quality roaming is required, it is recommended that the AP wireless coverage overlap range should be around 20%~30%, then the signal strength of the roaming test should not be less than -67dBm, and the signal-to-noise ratio should be at least 25dB. If the AP polarization mode is vertical + horizontal, then when the point is set, the corresponding APs on the upper and lower floors should also set different channels. Of course, many APs now support automatic channel selection, so you don't have to worry about it.
Roaming has the advantage of seamless roaming:
The setting is simple, the operation is inconvenient, but the layout is flexible, and no AP support is required.
Roaming drawbacks:
During the mobile process, because the AP is to be switched, but the roaming is performed by the wireless terminal itself, and the switching operation is performed by the wireless terminal itself, when the wireless terminal switches to the next AP, it is necessary to re-verify, switch channels, and send and receive information. However, when the wireless terminal itself handles the handover, the data is not sent or received, and the processing takes time, so a packet loss delay may occur in the middle. (According to the use of AP and mobile phone equipment, the drop-off time is uncertain, usually about 1 second)
Seamless roaming concept
Zero-HandoffRoaming or zero-switching,
What can be done by seamless roaming is that the switching time between the AP and the AP is controlled in the millisecond level, so basically no packet is lost, and there is no pause in the use of audio and video communication. It is equivalent to masquerading as an AP when multiple APs work, so that the client will not be disconnected when it is freely switched from one AP to another when moving. In the wireless roaming network, the client is configured and connected. The configuration in the in-point network is exactly the same, and the user does not feel the switching operation between the wireless APs during the mobile process. This is wireless seamless roaming.
Seamless roaming is used for mobile applications where the space is very large, there is a need for mobile communication, and the communication quality is very strict, and there is no need to interrupt any occasions when switching between aps, such as high-quality VIOP voice communication.
Distribution requirements:
a, all APs use the same SSID, (note that SSID is case sensitive)
b. Must use the same WEP or WPA encryption method and set the same password. If it is an open network, you can ignore this one.
c. All wireless APs need to be in a single LAN, which refers to the IP address of the same network segment.
d, the coverage between APs needs to be relatively overlapping, that is, the AP radius is 30 meters, then the distance between the two APs is preferably controlled within 50 meters. (The overlap range is around 20%~30%)
e. The channel between adjacent APs is manually selected and must be the same channel.
f. AC&AP is required to support wireless seamless roaming. Seamless roaming is the function of AC&AP, and AC&AP performs related handover work. (Generally all APs are the same manufacturer, same model)
Seamless roaming notes:
According to personal experience, if high-quality roaming is required, it is recommended that the AP wireless coverage overlap range should be around 20%~30%, then the signal strength of the roaming test should not be less than -67dBm, and the signal-to-noise ratio should be at least 25dB.
Seamless roaming compared to roaming advantages:
The setup is simple and easy to operate, but the layout is more difficult, and AP support is required. The delay is milliseconds, and the network delay is hardly felt.
Seamless roaming drawbacks:
Seamless roaming requires multiple APs to be masqueraded as an AP. This requires all APs to be set to use the same channel, so that the interference between your APs becomes very large, especially for smaller areas. In an indoor environment, deployment becomes very difficult. The same AP is required and the AP supports seamless roaming.
6. What software and hardware are required to deploy a wireless project?What software and hardware are required to deploy a wireless project?
Basic hardware: router, POE switch, AC, controller, wireless AP
High-end hardware: firewall router traffic and behavior management bypass main switch floor switch POE switch AC controller wireless AP
Is the power of the AP as large as possible?
No, the higher the power of the AP, the higher the signal strength of the transmitted signal. The literal understanding will lead you to the wrong zone. The stronger the signal, the better, but the signal strength is for the whole wireless network. The signal is on both sides. Both the transmitting end and the receiving end transmit data to each other. The signal at the transmitting end is too strong, which will inevitably affect the data transmitted by the receiving end. This will cause network transmission delay or packet loss.
Popular understanding:
In one space, you and another person are talking at the same time. The voice of the other party is too big, and your voice is very small, which will cause the other party to hear what you are saying, thus affecting the quality of the call.
Engineering perspective
a, design
The actual construction drawing, to determine the position of the wiring, need to consider such as: concealment, damage to the building (characteristics of the building structure), use of the existing space while avoiding the power line and other lines, the cable in the case of the scene, etc. Necessary and effective protection needs.
b, the location of the router
The router is generally used in the weak underground room (away from the strong electricity room to avoid strong electromagnetic interference), pay attention to ventilation, keep dry, it is best to have a cabinet, put together with the core switch.
c. Location of the POE power supply switch
POE switch location selection should be reasonable, located in the middle of the AP point, reducing the cost of routing and shortening the distance from the switch to the AP.
d, AP location selection
The point of the AP is arranged in the center of the selected scene, and is radiated to the periphery. The coverage of AP components should be overlapped to reduce signal dead zones. The distance between the AP and the POE switch should not exceed 80 meters (the original Amp network cable is an example)
e, laying of the network cable
As the transmission carrier of the network signal, the network cable should pay attention to the protection of the line during the laying process. Do not break or dead corners. If necessary, wear the iron pipe or place it in the roof bridge. Special attention is paid to the principle of high voltage wires to reduce interference with signals.
Practical operation and post-maintenance angle considerations
a, external network and routing:
The external network cable is in place to ensure the normal network access conditions, and the route is connected to ensure that the route itself can communicate normally. During the construction, the main exchange and the construction floor exchange are connected to ensure normal communication of the backbone network.
b. Debugging the intercom: In the commissioning phase, a set of intercom equipment needs to be seconded with the mall to facilitate debugging.
c. During the construction and commissioning phase, sufficient spare parts must be reserved for AP, switch, network cable, and other construction and debugging hardware.
d. Construction drawing: Before each construction, please ask the construction party to give us two construction drawings.
Construction network topology map: requirements, detailed floor switches, routing information and location, each layer of AP and other hardware and connection methods.
Construction equipment connection line identification map: requirements, routing and switch and AP connection information, corresponding ports, etc. All connection lines are theoretically approximate network line length (including between road-switch-AP).
e, construction wiring and line marking planning:
Information identification record: AP point Mac information record: When the construction party places the AP location, it needs to record the floor number and location number of the AP and the corresponding Mac information (note the corresponding floor plan AP number, for example: 1st floor 1st mac information format is 1F- 1 : AC: 11:22:33:44:AP ). This information is uniformly recorded on the floor plan of the Word document floor store by the floor distribution or directly recorded to the free space on the side of the construction drawing for convenient maintenance.
On each layer of the switch panel: need to indicate the identity or serial number, (the main switch of the connection route can be used 1F-1 ZSW or secondary (cascade) exchange available 2F-2CSW cascade exchange available 3F-1 JSW)
Line mark identification record:
(1) Input and output lines on the switch side: It is necessary to indicate which floor and location number of the AP is connected to the identification or serial number. (Note that the corresponding floor plan AP number, for example, the 1st floor and 1st format is 1F-1), The incoming line of the external network should also be wired: it needs to be marked as "external network access."
(2) Interconnection between all floor switches: At the head end of the line interconnection line of the switch, it is necessary to indicate the source of the identification or serial number. (Note that the upper floor and switch label are written, for example: 1st floor 1st switch, format 1F-1 SW)
f. Check whether the installed AP has power on, and work normally:
After the construction of the construction personnel is completed, all the APs are inspected and the power is normal. When the power is on, the green indicator light on the AP is on. If the route is in place and running, the software can detect whether the AP normally transmits signals and access the Internet.
g. If the above information is completely clear, then no construction personnel are required to be on site. If the above information is completely unclear, the construction personnel should cooperate with the construction personnel every time. (Large environment should be separately accepted after each floor is completed)
Nine, construction wiring precautionsIs the power of the AP as large as possible?
One: Hardware device interconnection notes:
1. Router to switch, switch to switch: Ordinary 450 one box of super five line (in use), recommended length of 70 meters or less (in special circumstances can be up to 90 meters, need to test in advance, before the wiring is not connected 90 meter line test.), Category 6 line, recommended length not more than 120 meters (to be tested), fiber, shopping mall environment is almost unlimited, but there are more considerations. (Beyond the above distance, the fiber is replaced by the fiber)
2. Switch to AP: Ordinary 450 one box of Super Category 5 (in use), it is recommended to be within 60 meters in length (up to 80 meters in special environment, need to test in advance, 80m line test before the wiring. ), six types of lines, the recommended length is not more than 100 meters (to be tested), fiber optics, shopping mall environment is almost unlimited, but there are more considerations. (Beyond the above distance, the fiber is replaced by the fiber)
3. If there is no enhanced signal equipment, the multi-switch equipment cascading mode recommends that the number of switches be controlled within 4, and the maximum number is no more than 6 (suitable for each segment of the shorter environment, but the data effect is not very good,)
4. All input (upper cascade) lines connected to the Poe switch must be connected to the UPLINK interface of the Poe switch.
5. In a non-standard POE power supply switch layout environment, use a line tester to test the connectivity of the network cable. If the network cable is plugged into the switch end, the line tester may be burned out. Note: The non-standard power supply is directly powered, and no handshake negotiation is performed.
| Between devices | Line class | Normal planning | Special planning | Special planning notes |
| Router to switch, switch to switch | Super five (normal) Category 6 fiber | 70 meters Within 100 meters, the mall environment is unlimited. | 90 meters 120 meters 10-20 km | In special circumstances, it can be up to 90 meters, and it needs to be tested in advance. The 90 meter line test is carried out on site before wiring. |
| Switch to AP | Super five (normal) Category 6 fiber | 60 meters Within 80 meters, the mall environment is unlimited. | Within 80 meters Within 100 meters 10-20 km | It can be up to 80 meters in special environment, and needs to be tested in advance. |
| Multi-switch cascading number | Eight-port Poe switch | Within 4 | 6 | Special environment can be extended by ordinary switch cascading mode or POE enhanced switch |
Fiber deployment considerations
1. Hardware information:
Single-mode single/double-core fiber can be used, both ends are welded and one core is used.
2. Construction attention:
Be careful not to subject the cable to heavy pressure or to be scratched by a hard object. In addition, the traction should not exceed the maximum laying tension.
Pay attention to the loose arc when placing and laying and arranging. There should be no twist in the middle. It is forbidden to hit the small ring to kill the knot (the smallest round of the palm), the turn should not be less than 90 degrees, and there should be no fold (straight) corner bend. , surges and other phenomena.
Be careful not to smash the welding position during construction. It is best to wrap the welding position and pull the line position behind it. The fiber optic connector should not be taken down during construction. It can be taken off during testing and covered when not in use.
Note that if the fiber is an indoor wire (thin and no peripheral gel material protection), it needs to be sleeved----plastic.
Note that when the fiber passes through the wall or through the floor, it is necessary to add a plastic tube with a protective cover, and fill the tube with a flame-retardant filler.
In short, be careful when wiring, do not damage, scratch, bend, break. And check it during construction, otherwise the subsequent maintenance is quite difficult.
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