Does an older device being used in the WIFI space of newer devices slow your overall connection speed?

Question

I inquired about certain things in regards to wifi connections with an expert on it in a reddit thread once, this was what he explained:

a 2010 iPhone will NEVER be able to get 200 Mbps download. That being said, if you had a first gen iPhone and three brand new MacBook pros, there is a high chance the internet may appear slow on those three laptops. TCP/IP is the communication portion of the internet. As packets get sent from one host computer to another, they get reassembled to ensure information is correct. If these packets are not assembled in the correct order you will have issues. So, if it receives too many incorrect packets, it will slow down the transmission to allow the packets to arrive properly. This can cause congestion. The first gen iPhone would be limited by its technology and so the modem/router would accommodate for its lack of ability. One way this can be done is by slowing down everything else. It may sound strange, but I have seen this be the cause of many issues. Once the older device is eliminated from the network, speeds tend to go up. It's the same logic when you think about 802.11G vs 802.11AC. I can give you 1 gig up and down in speed, but if you have an 802.11G router, your wireless will never go above 54 Mbps.

I'm quite uninitiated when it comes to networking terminologies, but what he explains seems to make sense to me. Before I bring it up in the future as a matter of fact, I was wondering if I could check the validity of his statements. (I'm leaning on it being the truth)

Edit: Ooookay, so, I don't who's correct here after reading the given answers, I'll leave the topic unmarked for answers.

Answer 1

First we need to clear up one big myth that's out there, and that's the idea that if an older device joins your network, that the whole network has to stop using all the faster technologies its capable of, and that everyone has to do everything the old way. That has never been true. If you had an 802.11g AP and clients, and then an 802.11b client joins, the 802.11g devices still use the faster 802.11g rates to speak to each other. It's not like everyone has to suddenly stop using G and all start using B exclusively just because a B client shows up.

That said, there are some, mostly minor, ways that the presence of an older client can cause the faster devices to not get quite as much throughput as they would have gotten without the slower device present.

One issue is that the slow client requires a lot more airtime than a faster client to transfer the same amount of data. Of course, even a state-of-the-art client, if it's too far away from the AP, may only be able to connect at slower data rates, and may use a lot of airtime to transfer a given amount of data. So this is just a common part of how 802.11 devices of all generations share the air. But with an older client, no matter what, even if it's close to the AP, it can never send data as fast as a more modern client might. So that can be a factor if the slow client has a lot of data to send or receive.

There are also a handful of minor performance tweaks that modern fast 802.11 devices can do to squeeze a few more percent efficiency out of the medium, that they can't do in the presence of older legacy 802.11 clients. So the presence of a legacy client can cause the fast client to have to stop using a few minor optimizations, and perhaps even enable a few tweaks to protect their transmissions from going undetected by (and thus getting clobbered by) legacy clients. These tweaks are mostly minor and certainly don't cause all the modern clients to get stuck at legacy rates.

Answer 2

No, this piece is so full if bad information that the only thing you can do with it is print it and then burn it.

Even when an old device join the network both central WAP can still talk at high speed to the fast client, but it will slow down while talking to the slow client. So a slow device just being there does not slow anything down at all.

if you want analogies: Think of is as a big discussion in a room:
You have 1 central person capable talking really fast.
You have 4 other people capable talking really fast.
You have one person who speaks slowly.

Everybody talks to the cental person. The fast people speak fast with hir, the slow people speak slow. As long as the central person is not busy all the time tying up the central persons time it will NOT slow down things.

TL;DR: Do not donload large stuff from the slow phone and things will not slow down.

Answer 3

My experience makes me agree with Pythonian. I have a hard-wired medical device joined to my WiFi network through an old D-Link 802.11b to ethernet adapter. It still works fine, but when the adapter is powered, even though the connected device is quiescent, the speed of the 2.4GHz network in the whole house suffers.

I reason from this that the WiFi connections of the more up to date devices aren't slowing down per se, but the network protocol has to work in tandem with the legacy device and even though it isn't generating original traffic, it is still participating in traffic management.

Thus, I keep it powered off, when not in use.

Answer 4

Yes - It is correct, although not quite on his protocol description. You are always bound by your slowest device. Let me give you the simplest (2.4GHz) example regarding the Wi-Fi standards. If you have an 802.11n wi-fi modem and all your devices support the 802.11n standard, you'll be buzzing at 802.11n rates which can reach 300Mbps (Theoretical). However, if an old 802.11b devices (11Mbps Theoretical) joins your wireless network, this will slow traffic down. For example, if you are on the freeway/highway and everyone is going 70mph and someone joins the freeway/highway going at 40mph - This will affect the overall traffic of the freeway. Same concept here, once a slow 802.11b device joins the wireless network, it too needs to pass traffic. It does so by sending packets in the air which tells everyone using the air (including the fast guys) that since my packets are slow, I will need more airtime to transmit my data. So, the fast movers, in turn have to buffer/hold their traffic until the slow moving packets are done... As you can see, this creates a bottleneck and slows down traffic.