221–230 of 242 posts
There is a German tech saying that goes "Wer Funk kennt, nimmt Kabel" ("Those who know wireless, use wires").
Funk means wireless ??
So German Funk is actually directly related to the English funk (as in music) etymologically.
Fortunately my Mac doesn't have Ethernet. Wait...
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Funk means wireless ??
Funk means RF/radio/wireless. The term originates from the first radio transmitter ever, which used spark gaps (spark = Funke, gap = Strecke/Spalte) to generate detectable RF. So German Funk is actually directly related to the English funk (as in music) etymologically.
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You can put the twin APs on different channels, and the two collision domains shouldn't overlap.
So he's specifically referring to collision on the same channel, not that a device connected to Router A on 2.4 channels 1->4, but can also see Router B on channels 10->13 has to wait to transmit data back to Router A.
You'll probably have to setup two different essids. Most devices I've used will keep using the same ap even when its signal is lousy and they have a great signal to the other ap
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On macOS, someone below recommended "WiFi Signal", USD 5. Not so fully featured, I assume, but free is Wireless Diagnostics. Ignore the popup, and go to Windows -> Info/Scan/Performance (it's in System -> Library -> CoreServices -> Applications, but I start it via Spotlight)
Fing for services and ping?
I build public Wi-Fi networks, you've probably used one of them. AMA if you have Wi-Fi questions. To say it "sucks" is a bit harsh. It's delivering multiple hundreds of Mbps to you via an unlicensed contention-based medium. The air interface is like sending packets over a noisy Ethernet hub; it's impressive it works as well as it does. That said, this article's a good primer on some of the protocol's fundamental chal…
Which router do you recommend? Is the 5G band consistently worse than the default (i.e. constant connection drops) or is that just my experience?
> In real life, if you had your devices close enough to each other and to the access point, about the best you could reasonably expect [with 802.11b] was 1 Mbps—about 125 KB/sec.
I used 802.11b a lot. In a non crowded situation reaching ~5.5mbit was not a problem at all. I remember seeing transfer speeds of about 700KB/s.
Why the author ignores the theoretical top speed which is something around ~60% of 11mbit is beyond me.
Then the author continues with the same thing again;
>your best case scenario [with 802.11g] tended to be about a tenth of that—5 Mbps or so
This again is not true. In a non crowded situation I had no issues reaching 2-3MB/s, which is closer to the theoretical limits of 802.11g after factoring in some signal loss.
Surely, today when everybody is having wifi you would probably not reach 700KB/s on 802.11b or 3MB/s on 802.11g, but back when it began it was actually feasible.
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In topic of building a multi-AP but with same SSID wifi network: Do I choose the same channel too or not? I have a wifi networks on a building built with brick and mortar, so I need more APs to cover the entire premise, there gonna be some overlaps in the coverage here and there...
No, set every AP to use the quietest channel. Using something like Wifi Analyzer on a phone positioned where the AP will be but with the AP off, see what's got the least going on... any loud APs on the same channel whether they're yours or not would be detrimental. Also completely avoid overlap. On 2.4 GHz that means 1, 6, 11. Also, if there will be so many APs that they will share channels, you want the APs physical…
The article misses out on explaining WHY we cannot get the promised bitrates. The answer is Shannon's limit on channel capacity, which mandates that you pay in either bandwidth or high power or low noise (SNR) to get higher capacity. Now these WiFi devices have internal rate adaptation algorithms that choose a particular modulation and coding scheme (MCS) index based on the measured SNR. A higher MCS index means bett…
> interference is considered as noise, which means that SNR simply drops You're arguing that PHY data rates are low because SNR is low, and SNR is low because interference is high. In my experience, this is not the case. PHY rates can be quite high, but the overall throughput is low due to inefficient channel access at the MAC layer. Wi-Fi doesn't consider interference as noise. Since it uses CSMA/CA to manage channe…
It is true that MAC backoffs are also a contributing factor to the throughput being low. The CCA assessment procedure detects both wifi preambles and non-WiFi interference (pure energy detection), which is why I say interference is modeled as noise. CCA does not for example, have some intelligent coexistence algorithm for dealing with zigbee or LTE-U or other ISM traffic.
[1]: http://www.revolutionwifi.net/revolutionwifi/2014/09/wi-fi-s...
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See my comment https://news.ycombinator.com/item?id=13793876 . I suggest reading Andrea Goldsmith's or Pramod Vishwanath's book on Wireless Communication. If not, Intro to Communication Systems by Madhow is recommended.
These look nice but they focus on the physical layer. Do you happen to know any useful English literature that covers the MAC layer of modern wifi standards (n, ac, ax)? Apart from the 802.11 standards, of course.
Book: https://www.pearsonhighered.com/program/Beard-Wireless-Commu...