Do 802.11n devices slow down a 802.11ac network?

Again. I repeat. No changes to any settings. In fact me plug off the AC and putting back the old extreme brings me back to good old days. No DSN settings. All same. Weird but true. My iPad is version 3.

There is something wrong with AC that will soon be corrected by Apple firwre update as always. I Joe hoping that they put faith in user concerns and address it. Thanks.

Ug. Can't edit, so I'll "edit via reply"

When I said 30%, that would be if the 11g device is really sucking up the bandwidth (say it's running some type of large file transfer operation). it's also not a hard number, just it would not be surprising to see an 11n network with an extremely active 11g device losing as much as 1/3 of it's possible throughout. Presumably, the same applies for 11ac, but there's so much bandwidth it may not matter.

OK, it's clear you're not interested in troubleshooting and have already decided what the issue is. Just take the 11ac back and be done with it. For all we know, there are, indeed, differences in settings you don't know about. It could be multicast rates, radio modes, transmit power... anything. Half of these settings you can't even access through Airport Utility 6.x. Given that you've now four times incorrectly spelled "DNS," I don't have much faith that you've got Airport Utility 5.6.1 installed to even know what half of the settings are. My 11ac is working better than myprevious AEx, so there's really no reason for me to try to troubleshoot yours.

Note to self: Don't try to help those who have already made up their minds on what the problem is.

wow all these responses and nothing real value :-) I will explain this the way I explain it to some of my clients who started looking wanting/needing faster speeds on their wireless networks. I'll start with what I think probably started this whole slowdown to lower speeds. Back when there was 11a and 11b all was happy along came 11g. 11g was faster than 11b because it was a mixture of 11a and 11b. to say that 11g was 2.4ghz frequency(11b freq) but used a 11a scheme of transferring data. during the timae when 11a/b/g routers came out introducing 11b in a 11g cause a significant speed difference but it wasn't 11g moving to 11b. (this will be explained shortly) you could verify this easiest using a windows machine and connect with 11g to the network and the connection speed usually said 54mb while the 11b whould show 22mb (these are never actually throughput 11g is around 22mb where 11b is 11mb dividing either one by half for send/recieve)

now I am gonna grab my broad stroke brush and say both 11n and 11ac are both 5ghz both use MIMO technology but here are the slight differences and where 11ac stands out. 11n uses both 5ghz and 2.4ghz 11ac is strictly 5ghz but the difference that seperates the men (11ac) from the boy (11n) is number of spatial steams due to the number of antennas 4 with 11n and 8 with 11ac and channel bandwidth for stations 11ac 80mhz compared to 11n at 40mhz. This alone helps out tremendously. Now for the reason introducing an 11n device into 11ac enviroment which I will say doesn't slow down connection speeds rather slows down how many times it needs to send data. In class the instructor explained all this theory behind this that and whatever but it boiled down to this. An 11ac router is much like your typical hub. eg.

for simpicity we are going to say 11ac througput is 1gb/s where 11n is 500mb/s and each connection gets 1 sec each round.

you have one 11ac machine connected and starts downloading 4gb file this takes 4seconds

you have two 11ac machines connected and they both start downloading file it would take first machine would be completed in 7 seconds and second machine in 8 seconds ex. m1 m2 m1 m2 m1 m2 m1 m2

now we have 3 machines one 11ac and two 11n. The 11ac machine would take 11 seconds and 11n machines would be 20 and 21 seconds to finish if the 11ac machine started the rotation.

This is why introducing an 11n into an 11ac network slows speeds down and obviously this exchange happens at faster than we can see or detect but this is as simple as I can describe it to someone with limited knowledge of networking and throughput across a network.

I am sure I just stirred up a hornets nest that was already laid to rest a few months back :-)

Thanks for this explanation, it really helps understand a little more about how it works

James McLaughlin wrote:

now we have 3 machines one 11ac and two 11n. The 11ac machine would take 11 seconds and 11n machines would be 20 and 21 seconds to finish if the 11ac machine started the rotation.

How would this be different than simply having 3 ac devices? Wouldn't the first ac device still finish in 11 seconds (or should that have been 10 seconds)?