20 votes
Accepted

Why does WLAN use Collision Avoidance and not Collison detection?

In a wired CSMA/CD Ethernet environment, it is possible to detect a collision because there are separate TX and RX pairs (using the example of 10BaseT). If a half-duplex 10BaseT NIC sends a frame on ...
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  • 26.7k
20 votes

Do WiFi and IEEE 802.11 mean the same thing?

IEEE 802.11 is a standard that describes procedures, limits, values, algorithms to enstablish a WLAN connection. Wi-Fi is a brand name owned by the Wi-Fi Alliance that certifies with pre-defined ...
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  • 301
19 votes

Why does WLAN use Collision Avoidance and not Collison detection?

Avoidance is used for the very simple fact that every radio ("client") is not necessarily in range of each other. Thus, without the AP coordinating who can talk, distant radios may step on each other ...
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18 votes
Accepted

Do WiFi and IEEE 802.11 mean the same thing?

Wi-Fi is IEEE 802.11, the same way that ethernet is IEEE 802.3, token ring is IEEE 802.5, FDDI is IEEE 802.8, etc. These are some of the IEEE LAN protocols, and the IEEE working groups associated ...
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15 votes

Do WiFi and IEEE 802.11 mean the same thing?

In Short,Wi-Fi is more of a technology name and 802.11 is the IEEE standard. There are different variants of 802.11 based on your bandwidth ,Modulation schemes etc. I would always use the specific ...
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  • 1,362
14 votes
Accepted

Four layer-2 addresses in 802.11 frame header

The distinction to understand is that while an 802.11 device is transmitting to a receiving device, either one (or both) of these devices may not be the actual source or destination of the L2 traffic. ...
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13 votes
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How does a WiFi range extender work?

There are two types of wireless extenders. First would be an extender that uses some sort of mesh technology. This type of extender is typically only found within an enterprise deployment and will ...
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12 votes

Can I truly multicast over WIFI?

As I understand Wifi, it can never true multicast, as each device holds a '1:1" relationship with the AP, and then receives the same packet... then the next device connects and gets the same ...
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  • 26.7k
11 votes
Accepted

How does a network know whether to send via internet/wifi or through cellular service?

In this scenario, your phone has at least two network interfaces: WLAN and 3G. Each interface has his own IP address and mask. They usually install as two routes on the phones routing table, the ...
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  • 1,152
11 votes
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WiFi planning for warehouse-sized location

Hire a professional who has warehouse experience. If you were using an enterprise vendor, I would suggest looking at their consulting services as they have probably done this with their products a ...
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11 votes
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Can I truly multicast over WIFI?

Lets test this out then. If we send multicast packets to multiple devices connected to a WiFi access point at a constant rate, then the access point should report the same amount of traffic. To run ...
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  • 134
11 votes
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How is the Groupwise Transient Key used in WiFi networks?

Why then does the client need to encrypt the broadcast using the GTK? It doesn't. Since the AP broadcasts, not the client, the client doesn't use the GTK to encrypt the frame. The AP does. Why can'...
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10 votes
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How to find the client who downloads a big file?

The easy way to do it could be: On your WLC home page you should have something like: You can reset the stat through the gear icon on the top right corner, selecting "Clear Dashboard Data" Then ...
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9 votes

Do WiFi and IEEE 802.11 mean the same thing?

802.11 are the IEEE specifications that implement wireless local area networks. In common parlance I think 802.11 is more or less synonomous with Wi-Fi. Note that Wi-Fi is actually a trademarked ...
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8 votes
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Raw-Ethernet Frames

First, Wi-Fi (IEEE 802.11) is not ethernet (IEEE 802.3) any more than token ring (IEEE 802.5) or any of the other IEEE LAN standards other than 802.3 are ethernet. The frame headers are different for ...
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  • 93.6k
8 votes

using fiberoptic for long-distance ethernet connection

Part 1: Using fiber to run a 1000 foot ethernet link Using fiber to run a long ethernet link is not quite as simple as you make out but it's certainly not unreasonable to DIY. A few things you have ...
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8 votes
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Are "ad-hoc" networks always wireless?

Caveat: This question might raise primarily opinion-based answers, and might be put on hold or considered off-topic, for exactly that reason. Still, I dare to attempt an answer: Following https://...
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8 votes
Accepted

Why do we have authentication before association in 802.11

Why does client authenticate before associating with the AP This does seem a bit odd. Yes, in modern 802.11 there is an open authentication that takes place before the association request/response. ...
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8 votes

Why is microwave faster than infrared as a transmission medium?

Faster in terms of propagation delay? @Zac67 answer is good. Faster in terms of data throughput? Here, infrared has a huge theoretical advantage. The whole microwave range consists of about 300GHz ...
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  • 169
7 votes
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Per-user network authentication without mac-filtering

I am aware of MAC address filtering available on most WiFi routers, but this is about access control on a device by device basis. One user may have many devices. Is there any way to control WiFi ...
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7 votes

Raw-Ethernet Frames

Based on your questions and comments, I think you are missing the point of the two articles you are referencing. When they are talking about "Raw Ethernet," they are talking about data frames that do ...
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7 votes
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Why would a WiFi extender use the same channel as the primary AP?

Simple, it only has one radio. One radio === one channel. If it has two (or more) radios, then it can use one for the mesh, and the others for clients. If your WLAN employs security, then every ...
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7 votes
Accepted

How to put special characters on ssid

Looks like an Emoji, hex code 1F193: 🆓 If the interface of your router allows it, you can simply copy and paste the above character on the SSID text field. Note: the style of the character will ...
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  • 1,289
7 votes

How are different phone/GSM operators connected with each other?

As simply as possible, telephone calls are routed across a network of switches which are interconnected using trunks. There are interconnect points for different operators/carriers' switches. Since ...
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  • 206
7 votes
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Alternatives to 802.11* wireless bridge?

are there any reasonable alternatives to 802.11 protocol being used nowadays for such links? Yes. The first that comes to mind is optical bridges (See FSO). They require line of sight, obviously. ...
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7 votes

Why is microwave faster than infrared as a transmission medium?

I've read that microwave is a faster medium of transmission of data than infrared. It's not. Light moves at the speed of light (c0), (pretty much) regardless of its wavelength - in reference to the ...
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  • 70.5k
7 votes

Why is microwave faster than infrared as a transmission medium?

Given the context which is severely outdated when not completely false, "infrared" seems to mostly refer to short-range low-bandwidth infrared communications as used: In many TV remote ...
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  • 653
6 votes
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Does IEEE 802.11ac imply Wi-Fi Direct compatibility?

The answer is no, the two are separate technologies. 802.11ac is the next generation of wifi, one step passed 802.11n. WiFi-Direct is just an on-demand autonegotiated ad-hoc wireless network. It could,...
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  • 1,783
6 votes
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Cannot use 5GHz band Wi-Fi from channels 100-140

Perhaps this will help. Also, consult Wikipedia for futher reference. In short, in the US, the H band is restricted due to interference issues with Terminal Doppler Weather Radar (TDWR). (at least ...
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6 votes

Cannot use 5GHz band Wi-Fi from channels 100-140

Radio frequency is a limited resource that is managed individually by various organizations geographically. In the US, the government entity that regulates the use of RF is the FCC. As of February ...
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