Newbie qn: What do I need to do to stop "dropout" between wifi router and extender

mephistophelean

Active Member
Apologies I am not a tech person and so may get terminology wrong.

I have a VM Hub 3 and was not getting wifi reaching all areas of my house. I had a TP Link RE 450 extender lying around (as you do) which I plugged in and used the TP Link Tether app to quickly extend the wifi and this has helped me get wifi coverage in those areas where we didn't get wifi.

The extender has the same wifi name as the the wifi name for the VM Hub 3 (which hopefully makes sense) to make things easier for all members of my family when connecting to the wifi.

However, when walking in areas between the VM Hub 3 and the extender and you are e.g. on a video call, we have noticed that the call drops, tries to reconnect and then does reconnect. It takes about 5 seconds to reconnect. I know it sounds like a minor issue (and is in the context of what is happening in the world) but it causes real annoyance to my family as we do a lot of video calls. My telling family members to not walk around the house while on a video call has not proved effective....

Is there a way of setting up the extender in a different way to stop this happening?

Would buying a mesh system solve this "drop"? I am conscious that it may be a sledgehammer to crack a nut but noticed that you can get TP Link mesh systems for what I need for about £100 to £150.
 

mickevh

Distinguished Member
There's always a "drop out"when a Wi-Fi client roams from one Access Point (AP) to another - it's just the nature of the beast - but usually it's so fast (ie tenths of a second ) you don't notice it. This is true of any Wi-Fi infrastructure including so-called "Mesh" systems.

However, it is rare but I have a TP-Link Repeater (RE200) that is a bit clumsy about how it handles roaming. The (my) Repeater does some kind of MAC Address proxying for all the clients attached to it that means whenever a client roams, it changes IP address. Such as change can be a bit slow depending in how efficient you client devices are at handling a DHCP refresh. Changing IP addresses out "under" a running application can break it. For example, copying a file will fail, but (in my case) streaming (say) YouTube seems to cope - probably because YouTube player is highly buffered and as far as the YouTube servers are concerned, due to the NAT in my router my (public) IP address hasn't changed.

Don't worry if you don't understand what any of that means - it is complicated. But I suggest a jumping off point would be to assess whether your Repeater is behaving like mine: Simply take a look at what the IP address of your clients are (check on the clients themselves, not your router) and see if their IP addresses change as they roam from router to repeater or vice versa.

If so, then changing to something (anything) that does not exhibit this behavour should "fix" it (I wouldn't buy my RE200 again and would check anything else does not work this way.) In more "normal" Wi-Fi systems, the AP's don't do this MAC Address proxying, so there's no requirement for clients to "refresh" their IP address whenever they "roam," (though some clients still do anyway,) but even if they do if they hang on to the same IP address as would happen in a well designed/behaving infrastructure, the clients survive the roaming operation without any drama.

I used to manage the network of a University campus with a largish Wi-Fi deployment (about 250 nodes) and when we were pushing out firmware upgrades to the AP's (which caused them to reboot) I'd watch entire classrooms of devices roam from one AP to another and the users were completely oblivious that it had happened. So it can be done.

So I suggest the first thing to do is establish whether your TP Link Repeater has them same (ahem) "fundamental design fault" mine has which might explain the behaviour you describe. If not, we can look for some other problem, if so, then perhaps it's time to consider replacing it.

Possibly the extender you have may be able to disable this "MAC Address Proxying" but mine does not - I just live with as it's not a major inconvenience to me.

I doubt you'd need to spend anything like GBP 150 unless you want an absolute top of the line AP with all the latest bells and whistles.
 
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mephistophelean

Active Member
Thank you @mickevh for your very comprehensive reply - I really appreciate your taking the time to talk me through things : I think I understood what you meant. I used my iPhone as the client and roamed around the house between router and extender. The IP address did not change. However, I did try different applications to see what would happen. When using YouTube as you commented on in your reply, there was no issues when I walked around the house. When I used WhatsApp video I still got the same buffering from walking from one area to the next.

I was wondering whether this issue was caused by my setting the extender wifi name to be the same as the router wifi name? I know the VM Hub 3 is not a mesh compatible solution (or at least not within another VM device).

Is there another possible solution or could it just be that I have a “faulty” AP (although as I said when you stay in one zone it works fine)?

Would you have any suggestions for an AP? (I suspect this is like asking how long is a piece of string….)

Edit: a bit more on the explanation of what I found
 
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mickevh

Distinguished Member
As an aside, how are you assessing whether a client is in session (called "Associated" in Wi-Fi speak) with the router or your Extender...? Do not "just assume" that because you are physically closer to one or the other that a client is Associated with the closest - Wi-Fi client devices do no constantly "hunt for the best signal." It's quite possible to be (literally) sat next to a Wi-Fi AP, but find the client it talking to one further away.

There is no real "right" and "wrong" way to do SSID naming, but it does have some consequences:

If you name SSID's (and passphrase) "the same" then client devices may automatically roam between AP's ("cells" if you will.) Note it is the client devices not "the system" that determine if/when to roam. Many clients offer little or no control over roaming behaviour and thusly we are in the hands of the device designer as to how aggressively they roam (or not.) iSomethings used to be notorious for not roaming ("in the business" - called it the"sticky client" problem.) Thusly, with SSID's the same, you never know (or can choose) which AP you are talking to without some forensic tools to check.

If you name SSID's differently, then you can be sure which AP you are talking to, but clients will never automatically roam between AP's (as they regard them as being "different" networks.) You have to flip the clients manually but so doing, you can be sure which you are using.

On big sites with dozens/hundreds of AP's the former is generally more convenient as most users lack the sophistication (or interest) to make choices about which AP they are using, but in small SOHO networks some people (who are sufficiently interested and with well trained households ) prefer to choose AP explicitly sacrificing automatic roaming.

To repeat, there's no real "right" and "wrong" was to do this - its matter of preference as to which you find most convenient/useful. Though most opt for "all the same."

Having both router and repeater named the same in and of itself is unlikely to be an issue - we do it all the time on big deployments. However, you might consider naming them differently (temporarily) for the purposes of testing, thusly being able to be sure which you are Associated with, but be mindful that in such as scenario automatic roaming won't happen by definition.

When fault finding on big systems, we sometime do this sort of thing for testing (though on enterprise kit there's more sophisticated toys that make it a bit less painful for the user population.)

There's no useful definition of what a "mesh" system is so it's surrounded by a lot of "marketing" BS. However, one of the things that is common is the implementation of a few newer protocols in the Wi-Fi standards that allow the AP's to send a kind of "hint" to client devices that they might do better roaming to another AP. For that to work, the client devices need to "hint compliant" ("take the hint" if you will) and many older clients are not. It also needs AP's that "talk" to each other to share information about (for example) who can "hear" which client the best. A hetergenious mix of AP's do not do this, so such "mesh" systems are often sold as an integrated solution with a single "management" platform. Nice little earner for the kit vendors. It's a bit of a "trickle down" to the SOHO marketplace of the sort of things we're had in enterprise systems pretty much forever.

I did a bit of Googling of your RE450 to see if is guilty of the same MAC Address Proxying my RE200 is, and I got the impression it is which may well be the root of you problems if so. Thusly, and in light of what I've said in this post about how roaming works, perhaps I could encourage you to do a bit more testing, maybe change the SSID's so they differ so you can control AP selection and be sure which you are Associated with, then go see if you get this IP changing issue. Failing that, find the DHCP Lease table in your router and post up a screen grab of it. It should not contain any information that is security sensitive. Depending on how it's annotated we may be able to spot whether there are clients with multiple MAC/IP addresses. (I have a Western Digital router, and it was looking at it's DHCP Table one day that clued me in that something weird was happening on my network and caused me to investigate further and discover my RE200 Repeaters "quirk.")

I do not recommend particular equipment on the basis that I do not see enough of it, nor have the appropriate test facilities (at home,) to make any useful recommendation. I quite like a guy who runs a web site called SmallNetBuilder who does a better job than many of objectively testing SOHO stuff and particularly I like that he publishes his testing methods and applies them consistently. However, he's in the USA so bear that in mind if you are outside that territory. Exact equipment spec. may differ elsewhere in the world - though often it's just the power supply and for Wi-Fi kit, the USA is allowed a bit more transmit power than (for example) European countries.
 
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mephistophelean

Active Member
As an aside, how are you assessing whether a client is in session (called "Associated" in Wi-Fi speak) with the router or your Extender...? Do not "just assume" that because you are physically closer to one or the other that a client is Associated with the closest - Wi-Fi client devices do no constantly "hunt for the best signal." It's quite possible to be (literally) sat next to a Wi-Fi AP, but find the client it talking to one further away.

Yes I realised this was going to be a problem when I started to do it.

I did two tests for this.

1) When I encountered the Whatsapp reconnecting issue, I checked the IP on my iphone before and after the issue. (The Whatsapp video reconnecting issue was very consistent so I could work do this consistently.)

2) I also stood next to the router and AP separately, disconnected from the WIFI and then reconnected to the wifi. My assumption was that if I was standing next to the router and AP respectively, the iPhone would connect to the strongest signal.

I did a bit of Googling of your RE450 to see if is guilty of the same MAC Address Proxying my RE200 is, and I got the impression it is which may well be the root of you problems if so. Thusly, and in light of what I've said in this post about how roaming works, perhaps I could encourage you to do a bit more testing, maybe change the SSID's so they differ so you can control AP selection and be sure which you are Associated with, then go see if you get this IP changing issue. Failing that, find the DHCP Lease table in your router and post up a screen grab of it. It should not contain any information that is security sensitive. Depending on how it's annotated we may be able to spot whether there are clients with multiple MAC/IP addresses. (I have a Western Digital router, and it was looking at it's DHCP Table one day that clued me in that something weird was happening on my network and caused me to investigate further and discover my RE200 Repeaters "quirk.")

Thanks for the suggestion. I will post the DHCP lease table below.



I do not recommend particular equipment on the basis that I do not see enough of it, nor have the appropriate test facilities (at home,) to make any useful recommendation. I quite like a guy who runs a web site called SmallNetBuilder who does a better job than many of objectively testing SOHO stuff and particularly I like that he publishes his testing methods and applies them consistently. However, he's in the USA so bear that in mind if you are outside that territory. Exact equipment spec. may differ elsewhere in the world - though often it's just the power supply and for Wi-Fi kit, the USA is allowed a bit more transmit power than (for example) European countries.

Much appreciated.
 

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mickevh

Distinguished Member
2) I also stood next to the router and AP separately, disconnected from the WIFI and then reconnected to the wifi. My assumption was that if I was standing next to the router and AP respectively, the iPhone would connect to the strongest signal.

Even then, a client does not necessarily "connect to the strongest signal." I did some test of this (with a different Wi-Fi product) some years ago on a site where pretty much everywhere on site I'd be "in range" of at least half a dozen AP's. To cite just one example, despite being literally sat underneath a (ceiling mounted) AP less that a meter above me, when I powered up my test device (a laptop,) it decided to Associate with an AP two floors above and about 10 meters "down the corridor." There's just no predicting it. (And with that same laptop - even with it's "roaming aggressiveness" NIC setting turned all the way up - I could walk past dozens of AP's and said laptop would not roam until I got nearly 70m away with a few fire door in between!)

Nothing really jumps out at me in your DHCP listing. A lot of the clients are named as "unknown" (client names in DHCP lists are very much as "optional extra," so that's not unusual behaviour in and of itself.) I suppose you could try identifying all your devices from their MAC Addresses to determine what is what, but that is a really thankless task which might not yield much additional information of any use.

However, I note one of the named clients is a laptop computer which would be my weapon of choice whenever diagnosing roaming behaviour issues. Partly, because it's "named" in your DHCP table making it easier to spot if it has multiple identities (though bear in mind if you ever connect it using ethernet, the lappy's ethernet and Wi-Fi NIC's get different IP addresses - that's normal) but also because one can do things on a laptop like easily find the IP address, run continuous pings and run up a free Wi-Fi scanner such as Acrylic Wi-Fi which - even with your SSID's all named the same - will identify all the AP's and which one you are currently Associated with.
 

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