802.11 WiFi

WiFi Channel Scanner

How to Forget a Wi-Fi Network in Mac OS X
If you do not see this communication, then you can investigate the network or the settings on the AP to see why it is not reaching the controller. TB Terrence Benjamin Jul 4, Network discovery is performed by listening to beacons and beacon transmission is shared by nodes in a BSSID each node has a beacon timer with a random backoff interval which is reset when a beacon matching the nodes network is received which tends to share the beacon transmission load. Is there an adapter for additional devices over the WiFi? Settings vary based on the router.

Navigation menu

WiFi Network troubleshooting

These bands are allowed to be used with low power transmitters, without requiring a license and with few restrictions. However, while unintended interference is common, users that have been found to knowingly cause deliberate interference to other users particularly for attempting to locally monopolise these bands for commercial purposes have been handed large fines. The base version of the standard was released in , and has had subsequent amendments.

The standard and amendments provide the basis for wireless network products using the Wi-Fi brand. While each amendment is officially revoked when it is incorporated in the latest version of the standard, the corporate world tends to market to the revisions because they concisely denote capabilities of their products. Wi-Fi operational range depends on factors such as the frequency band, radio power output, receiver sensitivity, antenna gain and antenna type as well as the modulation technique.

In addition, propagation characteristics of the signals can have a big impact. Compared to cell phones and similar technology, Wi-Fi transmitters are low power devices. To reach requirements for wireless LAN applications, Wi-Fi has higher power consumption compared to some other standards designed to support wireless personal area network PAN applications.

Other low-power technologies such as ZigBee have fairly long range, but much lower data rate. The high power consumption of Wi-Fi makes battery life in some mobile devices a concern. An access point compliant with either Higher gain rating dBi indicates further deviation generally toward the horizontal from a theoretical, perfect isotropic radiator , and therefore the antenna can project a usable signal further in particular directions, as compared to a similar output power on a more isotropic antenna.

Note that this assumes that radiation in the vertical is lost; this may not be the case in some situations, especially in large buildings or within a waveguide. On wireless routers with detachable antennas, it is possible to improve range by fitting upgraded antennas which have higher gain in particular directions.

Outdoor ranges can be improved to many kilometers through the use of high gain directional antennas at the router and remote device s. Some standards, such as IEEE Multiple antennas enable the equipment to focus on the far end device, reducing interference in other directions, and giving a stronger useful signal. This greatly increases range and network speed without exceeding the legal power limits.

Wi-Fi in the 2. For the best performance, a number of people only recommend using wireless networking as a supplement to wired networking. Researchers have developed a number of "no new wires" technologies to provide alternatives to Wi-Fi for applications in which Wi-Fi's indoor range is not adequate and where installing new wires such as CAT-6 is not possible or cost-effective. Many mobile devices also employ the cell phone networks to provide access to the Internet when out of range of Wi-Fi networks.

This is done, rather than rely entirely on cell networks as Wi-Fi networks are often cheaper for bulk data usage. With Wi-Fi signals line-of-sight usually works best, but Wi-Fi signals can be affected by absorption, reflection, and diffraction through and around structures. Due to the complex nature of radio propagation at typical Wi-Fi frequencies, particularly the effects of signal reflection off trees and buildings, algorithms can only approximately predict Wi-Fi signal strength for any given area in relation to a transmitter.

Mobile use of Wi-Fi over wider ranges is limited, for instance, to uses such as in an automobile moving from one hotspot to another. Other wireless technologies are more suitable for communicating with moving vehicles. Many newer consumer devices support the latest In the first quarter of , The Wi-Fi Alliance certifies devices compliant with the Various layer 2 variants of IEEE Across all flavours of This, however, does not apply to typical deployments in which data are being transferred between two endpoints of which at least one is typically connected to a wired infrastructure and the other endpoint is connected to an infrastructure via a wireless link.

This means that typically data frames pass an Due to the difference in the frame header lengths of these two media, the packet size of an application determines the speed of the data transfer. This means that an application which uses small packets e. VoIP creates a data flow with a high overhead traffic e.

Other factors which contribute to the overall application data rate are the speed with which the application transmits the packets i. The latter is determined by distance and by the configured output power of the communicating devices. The same references apply to the attached throughput graphs which show measurements of UDP throughput measurements.

Markers for traffic profiles of common applications are included as well. This text and measurements do not cover packet errors but information about this can be found at the above references. The table below shows the maximum achievable application specific UDP throughput in the same scenarios same references again with various different WLAN The measurement hosts have been 25 meters apart from each other; loss is again ignored.

Increasing the number of Wi-Fi access points for a network provides redundancy , better range, support for fast roaming and increased overall network-capacity by using more channels or by defining smaller cells. Except for the smallest implementations such as home or small office networks , Wi-Fi implementations have moved toward "thin" access points, with more of the network intelligence housed in a centralized network appliance, relegating individual access points to the role of "dumb" transceivers.

Outdoor applications may use mesh topologies. When multiple access points are deployed they are often configured with the same SSID [ clarification needed ] and any security settings to form an "extended service set". Wi-Fi client devices will typically connect to the access point that can provide the strongest signal within that service set.

Wi-Fi allows wireless deployment of local area networks LANs. Also, spaces where cables cannot be run, such as outdoor areas and historical buildings, can host wireless LANs. However, building walls of certain materials, such as stone with high metal content, can block Wi-Fi signals. Since the early s manufacturers are building wireless network adapters into most laptops. The price of chipsets for Wi-Fi continues to drop, making it an economical networking option included in even more devices.

Different competitive brands of access points and client network-interfaces can inter-operate at a basic level of service. Unlike mobile phones , any standard Wi-Fi device will work anywhere in the world. An access point resembles a network hub , relaying data between connected wireless devices in addition to a usually single connected wired device, most often an Ethernet hub or switch, allowing wireless devices to communicate with other wired devices.

Wireless adapters allow devices to connect to a wireless network. As of [update] , most newer laptop computers come equipped with built in internal adapters.

A wireless router allows all three devices, mainly the access point and router, to be configured through one central utility. This utility is usually an integrated web server that is accessible to wired and wireless LAN clients and often optionally to WAN clients. Wireless network bridges connect a wired network to a wireless network.

A bridge differs from an access point: Two wireless bridges may be used to connect two wired networks over a wireless link, useful in situations where a wired connection may be unavailable, such as between two separate homes or for devices which do not have wireless networking capability but have wired networking capability , such as consumer entertainment devices ; alternatively, a wireless bridge can be used to enable a device which supports a wired connection to operate at a wireless networking standard which is faster than supported by the wireless network connectivity feature external dongle or inbuilt supported by the device e.

Wireless range-extenders or wireless repeaters can extend the range of an existing wireless network. Strategically placed range-extenders can elongate a signal area or allow for the signal area to reach around barriers such as those pertaining in L-shaped corridors. Wireless devices connected through repeaters will suffer from an increased latency for each hop, as well as from a reduction in the maximum data throughput that is available.

In addition, the effect of additional users using a network employing wireless range-extenders is to consume the available bandwidth faster than would be the case whereby a single user migrates around a network employing extenders. For this reason, wireless range-extenders work best in networks supporting very low traffic throughput requirements, such as for cases whereby a single user with a Wi-Fi equipped tablet migrates around the combined extended and non-extended portions of the total connected network.

Also, a wireless device connected to any of the repeaters in the chain will have a data throughput that is limited by the "weakest link" existing in the chain between where the connection originates and where the connection ends. Networks employing wireless extenders are more prone to degradation from interference from neighboring access points that border portions of the extended network and that happen to occupy the same channel as the extended network.

The security standard, Wi-Fi Protected Setup , allows embedded devices with limited graphical user interface to connect to the Internet with ease. Wi-Fi Protected Setup has 2 configurations: These embedded devices are also called The Internet of Things and are low-power, battery-operated embedded systems. Increasingly in the last few years particularly as of [update] , embedded Wi-Fi modules have become available that incorporate a real-time operating system and provide a simple means of wirelessly enabling any device which has and communicates via a serial port.

An example is a portable ECG device monitoring a patient at home. This Wi-Fi-enabled device can communicate via the Internet. It makes embedded systems with Wi-Fi connectivity possible to build as single-chip devices, which reduces their cost and minimum size, making it more practical to build wireless-networked controllers into inexpensive ordinary objects.

The main issue with wireless network security is its simplified access to the network compared to traditional wired networks such as Ethernet. With wired networking, one must either gain access to a building physically connecting into the internal network , or break through an external firewall.

To enable Wi-Fi, one merely needs to be within the range of the Wi-Fi network. Most business networks protect sensitive data and systems by attempting to disallow external access. Enabling wireless connectivity reduces security if the network uses inadequate or no encryption.

An attacker who has gained access to a Wi-Fi network router can initiate a DNS spoofing attack against any other user of the network by forging a response before the queried DNS server has a chance to reply. A common measure to deter unauthorized users involves hiding the access point's name by disabling the SSID broadcast. While effective against the casual user, it is ineffective as a security method because the SSID is broadcast in the clear in response to a client SSID query.

Another method is to only allow computers with known MAC addresses to join the network, [82] but determined eavesdroppers may be able to join the network by spoofing an authorized address. Wired Equivalent Privacy WEP encryption was designed to protect against casual snooping but it is no longer considered secure.

WPA was specifically designed to work with older equipment usually through a firmware upgrade. The only remedy as of late is to turn off Wi-Fi Protected Setup, [87] which is not always possible. Virtual Private Networks are often used to secure Wi-Fi. The older wireless encryption -standard, Wired Equivalent Privacy WEP , has been shown to be easily breakable even when correctly configured.

Wi-Fi access points typically default to an encryption-free open mode. Novice users benefit from a zero-configuration device that works out-of-the-box, but this default does not enable any wireless security , providing open wireless access to a LAN.

To turn security on requires the user to configure the device, usually via a software graphical user interface GUI. On unencrypted Wi-Fi networks connecting devices can monitor and record data including personal information. Piggybacking refers to access to a wireless Internet connection by bringing one's own computer within the range of another's wireless connection, and using that service without the subscriber's explicit permission or knowledge.

During the early popular adoption of Recreational logging and mapping of other people's access points has become known as wardriving. Indeed, many access points are intentionally installed without security turned on so that they can be used as a free service. Providing access to one's Internet connection in this fashion may breach the Terms of Service or contract with the ISP.

These activities do not result in sanctions in most jurisdictions; however, legislation and case law differ considerably across the world. A proposal to leave graffiti describing available services was called warchalking. A user who happens to start up a laptop in the vicinity of an access point may find the computer has joined the network without any visible indication.

Moreover, a user intending to join one network may instead end up on another one if the latter has a stronger signal. In combination with automatic discovery of other network resources see DHCP and Zeroconf this could possibly lead wireless users to send sensitive data to the wrong middle-man when seeking a destination see Man-in-the-middle attack. For example, a user could inadvertently use an unsecure network to log into a website , thereby making the login credentials available to anyone listening, if the website uses an unsecure protocol such as plain HTTP without TLS HTTPS.

The World Health Organization WHO says "no health effects are expected from exposure to RF fields from base stations and wireless networks", but notes that they promote research into effects from other RF sources. The United Kingdom's Health Protection Agency reported in that exposure to Wi-Fi for a year results in the "same amount of radiation from a minute mobile phone call".

A review of studies involving people who claimed electromagnetic hypersensitivity , " From Wikipedia, the free encyclopedia. Mobile phone radiation and health Wireless electronic devices and health International Telecommunication Union Radio Regulations.

Beam steering Beam tilt Beamforming Small cell. Electromagnetic interference at 2. This article needs to be updated. Please update this article to reflect recent events or newly available information. This article needs additional citations for verification.

Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. May Learn how and when to remove this template message. Wireless electronic devices and health. Archived from the original on Archived from the original txt on September 28, Archived from the original on November 7, Archived from the original on January 2, Archived from the original on 31 December Retrieved 11 June Archived from the original on 13 June The Sydney Morning Herald.

Archived from the original on September 17, Official industry association Web site. Archived from the original on September 3, Retrieved August 23, Archived from the original on 4 June Retrieved 8 June Archived from the original on 9 August Enter your email address below:.

Sorry but this is one thing that Windows does so much better than Mac. Forget a network by right-click and choosing forget. Much faster and more intuitive. Pull the other one. I have icloud keychain enabled. Any ideas on how to realise that? It does not work at all. A link on one article to the same article. This the method in the article does not work at least not in OS X Can someone brilliant troubleshoot this?

Hi, this method is useful to delete preferred networks, but what about other networks proposed like free-wifi etc. I want to rejoin a network with different login details than the one it has stored. It still connects without prompting me to put in the new password for the wifi. I have no issues connecting on my iPhone 6 because I can simply forget the wifi and comeback and input the new password, not possible on OS X Yosemite This is really annoying.

I tried to use this method but it did not work for me. I also needed to put in a new password to a network I was already using. I tried to click on the alert connections and add the network I was on with the new password.

WPA personal, etc in and the new password. I did it twice and it took the second time because I wrote it exactly how it was written with upper and lower case in the proper place. Hopefully this will help someone else. Extra question, is it somehow possible to see when you last connected to each network? This way I can delete very old networks. After u follow the above mentioned instructions.. Just join some other network available on ur WiFi scroll down menu. So type some random password and click ok then try reconnecting to your network..

It asks you for Your new password. Type it in and your ready to go. This tip is just wrong — old networks keep reappearing even after they have been deleted. I have a list going back to at least , even though this is my third iMac and third iPhone since then.

If the network is in range, it will reappear. Forgetting a network disconnects it and prevents auto-joining if it sees it again. I have as Michael old networks from past travels re-appearing in the Preferred Network, even after having been deleted and never been in the range of those networks since the deletion.

Some deleted network never re-appear, and some deleted networks re-appear after months. We need a method for deleting unwanted networks permanently. Hi, I travel a lot and I have exactly the same problem many have complained about. I delete about 50 wifi networks I no longer use, but they keep reappearing. I looked in keychain — they are not there. It is driving me insane. I delete the networks, I press accept, I close the computer and restart it — and back they all come.

What can I do please. I have followed all directions on this tread, which are the same as all other threads I have read. I get to 4 of the pictured directions at the top of the page, and what I want to remove is not there. I have also gone into utilities, keychain, and what I want to remove is not there, under any of the keychains or categories.

What I want to remove is the name of my personal router and extender, I no longer have them, I have new ones with new names. Those Wi-Fi hotspots keep reappearance even after you delete them on your Mac is because they are all originated from your iPhones.

You will need to dis-associate your keychain from the iCloud storage and then they will be gone for good and Mac OS will not try to re-sync Wi-Fi hotspots again.

To dis-associate the keychain: There is a catch: Your iCloud keychain may not be able to uncheck. The moment you uncheck it and it checks itself back again after a couple of seconds. You will have to delete the Keychain preference folder completely in order for it to reset itself and for it to work.

Context Navigation

Leave a Reply

Reader Approved How to Improve WiFi Reception. Three Parts: Improving WiFi reception at home Using kitchen foil Traveling Community Q&A Wi-Fi networks have a range that's limited by the transmission power, antenna type, the location they're used in, and the environment. A media access control address (MAC address) of a device is a unique identifier assigned to a network interface controller (NIC) for communications at the data link layer of a network segment. MAC addresses are used as a network address for most IEEE network technologies, including Ethernet and food-combination.ga this context, MAC addresses are used in the medium access control . WiFi Channel Scanner. About. WiFi Channel Scanner is a free WiFi network scan tool, it can quickly search and identify WiFi hotspots around you. It will provide all important WiFi network information, including network name (SSID), channel, signal quality, authentication algorithm, cipher algorithm, MAC address and more.