Contents1Purpose2Introduction to WiFi technology2.1About the IEEE 802.11 Standard2.2About the 2.4 GHz WiFi Band2.3About the 5 GHz WiFi Band2.4Antenna Characteristics3ONT’s WiFi installation3.12.4 GHz Interference Sources3.1.1CoChannel interference3.1.2Neighboring channel interference3.1.3Non802.11 interference3.2WiFi attenuation3.3Instruction on installation of ONT3.4Instruction for installing anten angle4Expanding WiFi coveragereach4.1WiFi Bridges4.2Wireless Repeaters or Extenders5Troubleshooting WiFi performance5.1Tools and techniques to indentify the WiFi issues5.1.1Ping to some application server5.1.2WiFi network analyzer5.2Solution5.2.1Verifying the ONT’s position and Antenna orientation5.2.2Checking the RF environment5.2.3Priority consideration6Glossary of terms
Robert_Cuong Wi-Fi installation and troubleshoot Client Guide WiFi Basic knowledge 2-3-2023 Wifi installation and troubleshoot Contents Purpose 2 Introduction to Wi-Fi technology 2.1 About the IEEE 802.11 Standard 2.2 About the 2.4 GHz Wi-Fi Band 2.3 About the GHz Wi-Fi Band 2.4 Antenna Characteristics ONT’s Wi-Fi installation 3.1 3.1.1 Co-Channel interference 3.1.2 Neighboring channel interference 3.1.3 Non-802.11 interference 3.2 Wi-Fi attenuation 3.3 Instruction on installation of ONT 3.4 Instruction for installing anten angle Expanding Wi-Fi coverage/reach 4.1 Wi-Fi Bridges 4.2 Wireless Repeaters or Extenders Troubleshooting Wi-Fi performance 5.1 Tools and techniques to indentify the Wi-Fi issues 5.1.1 Ping to some application server 5.1.2 Wi-Fi network analyzer 5.2 2.4 GHz Interference Sources Solution 5.2.1 Verifying the ONT’s position and Antenna orientation 10 5.2.2 Checking the RF environment 11 5.2.3 Priority consideration 12 Glossary of terms 12 Page of 13 Version 1.1 Wifi installation and troubleshoot Purpose Understanding the operation and limitations of wireless networks helps the user optimize the role of wireless networking in their home network Equip technical staff with knowledge and testing tools to provide best practices with respect to locating, setting up, and troubleshooting a wireless network with DASAN ONT products General introduction of Wifi technology, instructions to set the location of Wifi devices, guide to adjust Wifi antenna angle, guide to deploy Wifi device in some typical areas Introduction to Wi-Fi technology 2.1 About the IEEE 802.11 Standard According to Wikipedia, "Wi-Fi, which stands for Wireless Fidelity or 802.11 network, is a wireless network that uses radio waves, like cell phones, televisions and radios Current wifi technology uses two bands of 2.4Ghz and 5GHz with the following basic characteristics 2.2 About the 2.4 GHz Wi-Fi Band Wi-Fi (IEEE 802.11) makes use of 20 MHz wide channels in the 2.4 GHz band Working frequency from 2402Mhz to 2494Mhz range devided into 13 + channels, that are spaced MHz apart The width of each channel is 20 Mhz or 40 Mhz If we use 20Mhz channel width, there will be channels that not overlap Normally people will choose channels 1, and 11 as shown below Page of 13 Version 1.1 Wifi installation and troubleshoot 2.3 About the GHz Wi-Fi Band The GHz frequency band has considerably more available spectrum than the 2.4 GHz band, and none of the 20 MHz-wide channels overlap, working frequency from 5170 Mhz to 5845 Mhz range There are 23 x 20 Mhz channels; 11 x 40 Mhz channels; x 80 Mhz channels The width of each channel is 20Mhz default, can expand the width of each channel up to 160Mhz as follows 2.4 Antenna Characteristics DASAN ONT use omnidirectional antenna with type of dBi, which commonly used indoors to provide coverage throughout an entire space Devices directly above or below the omnidirectional antenna may have a very weak signal or even be unable to detect the signal This is due to the primary signal being focused outwardly on a horizontal plane Page of 13 Version 1.1 Wifi installation and troubleshoot ONT’s Wi-Fi installation 3.1 2.4 GHz Interference Sources Most interference in wireless networks occurs in the 2.4 GHz band Follows is a partial list of "interferers" and their relative effect on Wi-Fi signals 3.1.1 Co-Channel interference Whenever one transmitter’s signal overlaps another on a frequency or channel, the signals interfere with each other Wireless LAN devices must contend for use of the airtime; if nobody is transmitting at a given time, someone may use the channel When both transmitters are busy sending data, the channel can become very congested The two signals begin to interfere and cause data corruption, which causes devices to retransmit lost data, which uses more airtime Having at least 19-dB separation helps maintain a healthy signal-to-noise ratio (SNR) in the area surrounding the transmitter 3.1.2 Neighboring channel interference Suppose that two transmitters are placed on two different channels However, the channels are spaced too closely together such that they overlap each other No one is taking turns, and the transmissions of each of the radios simply trample the transmissions of the other The data transmission of both networks is seriously degraded For this reason co-channel interference is much preferable to overlapping channel interference Page of 13 Version 1.1 Wifi installation and troubleshoot In some cases, even adjacent (non-overlapping) channels may cause interference if the adjacent signals are high enough that the receiver filter cannot eliminate the interference 3.1.3 Non-802.11 interference In practice, such an elegant solution might not be possible Many non-802.11 devices not sit on any one channel 3.2 Wi-Fi attenuation Physical obstruction interferences Page of 13 Version 1.1 Wifi installation and troubleshoot Attenuation and weak signals Note: Wi-Fi signal power at receiver >= -60 dBm is a guaranteed power level for good data transmission If signal < -60 dBm is a weak Wi-Fi power level, not guaranteed to transmit data Especially if the signal < -85 dBm, the transmition is unstable or some time disconnected 3.3 Instruction on installation of ONT Place ONT in the central location of the house or as close to areas of wifi clients as possible (living room, bedroom, office ) Place far from some Non-802.11 interference devices as microwave ovens, wireless mouse, speaker, TV, … Avoid some obstructions which make Wi-Fi signal loss much power as iron doors, aluminum door frames, fish tanks, brick/concrete walls Place at 1.5m high to get the strongest beam of Wi-Fi antenna Put the ONT on the floor is the worst position, because then the wifi signal spread on the floor and met a lot of obstacles so that the receiver did not reach the main beam, only could access the reflection 3.4 Instruction for installing anten angle Antenna Angle = 900 helps the wave propagate in the horizontal direction, it is suitable for homes with a floor surface Page of 13 Version 1.1 Wifi installation and troubleshoot When set antenna angle = 900 and the other angle = 00, which make wifi waves transmitted both horizontally and vertically with the need of coverage for both upper and lower floors Expanding Wi-Fi coverage/reach 4.1 Wi-Fi Bridges House include a lot of floors, we can expand Wi-Fi coverage by adding Wireless access point to ONT via LAN cable (CAT5) Users typically enjoy increased performance, network simplicity, flexibility, control and can easily add more access point ONT can connect to Wan or Lan of access point: Via Wan: Lan’s network of access point which supply ip address to clients have different subnet mask with Wan network Via Lan: ONT supply ip address to clients connecting to ONT or access point, dhcp server of lan side of access point will be disable 4.2 Wireless Repeaters or Extenders Wireless repeater or extender is a device that receives the Wi-Fi signal from the Wi-Fi enabled Router/Gateway, and retransmits it When a repeater is introduced into the network, transmissions will double and delays are potentially introduced Depending upon the capabilities of the repeater, it can use the same Service Set Identifier (SSID) or a different SSID A single SSID may enhance the client's ability to roam from the extender to the AP and back depending on movement of the client within the home When two SSID's are used some of the units that support a second SSID will use a different channel for that second SSID the repeater must have dual radios The use of a second channel allows the repeater to receive and transmit simultaneously and eliminates the halving of the bandwidth Page of 13 Version 1.1 Wifi installation and troubleshoot Troubleshooting Wi-Fi performance 5.1 Tools and techniques to indentify the Wi-Fi issues To identify slow, unstable network due to Wi-Fi, use a laptop with two types of network cards: Wi-Fi and LAN To troubleshoot the internet problem, we have to find the problem come from where? Including Wi-Fi clients? Environment ? ONT ? Uplink network ? or Application server ? To get Wi-Fi interference, you should use some Wi-Fi application tool then take capture of the environment Download the log file of ONT, so that we can analyze if any potential problem come from ONT Please get syslog of ONT as below step: Log in to ONT and go to Advanve Setup section Capture the ONT info: GPON SN, ONT version, … Follow path: Mainternance \ Logs \ System log and Download all Syslog in the box "System log" on the right and save as file: Page of 13 Version 1.1 Wifi installation and troubleshoot 5.1.1 Ping to some application server Used to test the connection as well as the quality of the connection through the results of reply, round trip delay time Ping to ONT and Internet many times over both LAN and Wi-Fi Then calculate the average and record the test results (lost packet, average delay) in the following table: LAN to ONT A LAN to Internet B Wifi to ONT C Wifi to Internet D If A, B, C, D is almost equivalent: good network If A&B are equal, C&D is equivalent but A&B are much better than C&D: Need to verify more about Wi-Fi part If both A&C are equal, B&D is equal but A&C is much better than B&D: Need to verify the Uplink network 5.1.2 Wi-Fi network analyzer You can download and use some of the wifi analysis software as: Wifi analyze on android phone https://play.google.com/store/apps/details?id=com.farproc.wifi.analyzer Acrylic Wifi Free on Windows https://www.acrylicwifi.com/en/wlan-wifi-wireless-network-software-tools/wlanscanner-acrylic-wifi-free/ Wifi Explorer on MAC http: // www adriangranados.com / apps / wifi-explorer 5.2 Solution To ensure the quality of the wifi signal, access points in the same area should run on different wifi channels to avoid interference and congestion that affects the signal Therefore, it is necessary to adjust the location of the AP and the Wi-Fi channel so that received power ensure: The radius of cell should be better than -67 dBm The distance between two Access Points from the radius of the area Its coverage is more than 19 dBm Page of 13 Version 1.1 Wifi installation and troubleshoot 5.2.1 Verifying the ONT’s position and Antenna orientation AP get broken antenna or cable connect to the antenna and main board broken: When the measured signal strength wifi at a distance of 5m which received power of the tester through tools or software at