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I'm wondering, is there any wifi latency problems? Like, say this was taken to an extreme though. Like we had a wifi repeater. The repeater consisting of a receiver, which then immediately repeats the signal to an access point, but under a different SSID(I do not need this to all work as one network). The repeater could make it so I could have no need for wires for a very long distance, though it could require quite a few repeaters(more than 4). Assuming the software is as fast as the hardware, could there be any latency probelms with this also assuming that all the repeaters were within full-speed distance of each other?

Also, could this depend on hardware? or is the wifi standard designed to be latency free?

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If a satellite link is somewhere in the picture, even bad wifi links come no where near the 550-600ms due to the satelite hop. So what if you add 10-50ms with some repeaters.

I dont have much experience with low end "wifi" but stuff like mikrotik we can do 2-4 hops, each 8km and the latency stays 10-20ms with low load. But that is a good one. On our bad ones (alvarion old stuff) with several hops is can be 100ms over 16km when loaded. But i have seen people connect offices with wifi links and dont notice a difference browsing. You might have more jitter with VoIP.

equipment that uses frequency hopping as opposed to Direct Sequence has higher latency. I dont think FH is used much anymore.

If loads are high latency goes up.

Some DSL modems will work back to back, might be an option for you. wires are easier to troubleshoot in congested areas.

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Assuming you're talking about transmitting and receiving data this has more to do with the protocol that you're using than "wifi latency". Wireless networks generally have more latency than wired networks, but all networks have latency.

A low latency network might be perceived as "fast" by a user and a high latency network will almost definitely be perceived as being slow. But bandwidth is another part of the puzzle depending on what you're using the network for. You might want to check out latency, bandwidth, and TCP/IP on wikipedia.

TCP and IP are two network data protocols that help data arrive, and arrive correctly. For a very brief and certainly not 100% accurate explanation IP (Internet protocol) gets the data there, and TCP (transmission control protocol) makes sure the data that arrives is in the correct order so that it can be correctly interpreted.

Wireless networks generally have a higher bit error rate than wired networks and can cause what is known as packet loss. The more complex the wireless network is, the more likely packet loss will occur.

All of these concepts are just part of the large puzzle that is wireless networking, and all of them can be gone into in much more depth than is appropriate for this text box. Doing some research into TCP/IP will likely give you a much better understanding.

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Latency problems in what sense? At the TCP level each link is another hop, so there's no problem there. At the application level, it depends on if they're sensitive to timeouts and the like - trying to stream video over such a network is likely a poor plan, but your ssh session should work okay.

Nothing is latency free - the speed of light is not just a good idea, it's the law :) Radio waves are always approximately the speed of light - the real bottleneck is going to be the packet processing at each end, which depends a fair bit on the wifi chipset and cpu of the machines in question. A good wireless link should have fairly (within 10-20%) comparable latencies to the wired ones you mention. Satellite has high latency due to the large distances involved (wikipedia has some info on satellite latency)

That said, sitting across the room from my wifi router (a wrt54gl) ping shows latencies of from 1 to 6 ms. There are a couple of other low traffic devices using it as well, but it's also not exactly a beefy box.

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Well, I mean comparable to "natural" internet speeds, such as cable and DSL, not like the hella latent satellite connection I have. –  Earlz Jul 7 '09 at 3:58
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