How does Xiaomi Mesh know which router the phone is connected to? That night when the master bedroom was stuck in the living room, I tried all the methods to determine the nodes.

I set up the Mesh network at home the year before last. I placed the main router AX6S in the living room and the Redmi AX3000 as a sub-router in the master bedroom on the second floor. I haven’t taken care of it for more than a year since then. Something happened at the end of last month: At ten o'clock in the evening, I was watching a live football match on my mobile phone in the master bedroom. The screen was stuck in a mosaic and the sound was intermittent. ； Go downstairs to the living room, use the same phone and the same app, and everything will be smooth immediately. It's the same pattern for both trips back and forth - it's better to get stuck upstairs and downstairs.

In the single-routing era, this matter is easy to judge, but the signal is poor. But after Mesh networking, the whole house has one WiFi name, and the signal on the mobile phone screen always displays a full bar (it shows the signal of the "currently connected node"). You have no idea whether behind this mosaic, the phone is holding the AX6S in the living room, the router above the head, or simply communicating with the one downstairs through the floor. That day, I spent the whole night thinking about "how to know which phone the phone is connected to". I tried all three ways to check it, and I also dug out an unpopular switch hidden in the Mijia App. Let’s talk about the conclusion first: I can check it, but every path has its own temper, and there is one old firmware that doesn’t have it at all. .

Why is this worth understanding first?: Mesh lag is most likely caused by "connecting to the wrong person"」

Keep your logic in mind first, otherwise the investigation will be in vain. The selling point of Mesh networking is seamless roaming: The whole house has one name, and the mobile phone chooses the node with the best signal to connect to. But when it comes to "choosing it yourself", mobile phones are not very smart - when to switch or not, the decision lies with the mobile phone and not the router. Each mobile phone has its own temperament. I have figured out this mechanism before when I was studying roaming stickiness. The article written on Mesh roaming without switching Here, we called this "stickiness" at the time.」: The mobile phone obviously walked to the sub-router, but still clung to the main router. The signal was weakened by the floor, and the speed dropped accordingly. The performance was that the icons were full and the icons were displayed as PPT.

That was the situation in my master bedroom that night. But there is another converse situation that you should also be aware of.: The mobile phone finally switched to the sub-router, and the result The leg (return leg) of the sub-router that returns to the main router is too thin. ——For example, the wireless backhaul signal is suppressed by a load-bearing wall, and the mobile phone is connected to the sub-router at full capacity, but the sub-router is only transmitted back to the main router at half speed. If it is used at both ends, the lag remains the same. These two diseases look exactly the same, but the prescriptions are completely opposite.: The former requires driving the mobile phone to the sub-router (or adjusting roaming parameters), while the latter requires fixing the location of the sub-router or the return method. Without first figuring out which phone your phone is connected to, you'll just have to guess how you adjust it.

So the order should be: Determine the node first, then decide on the plan . Xiaomi provides more than one entrance to determine the node, but it is scattered in the Mijia App, web background and the system information of the phone itself. The following is in the order of my actual test.

first stop: The Mesh topology map of Mijia App is the most intuitive but has blind spots

Mijia App is where most people manage Xiaomi routers. Let’s talk about it first. Open the App and enter the page of the main router device you have bound, and look for the entry related to "Mesh Networking" (for my device, click "Add Mesh Network Device" on the device page to enter the network management page. After entering, you can see the network status and the list of added sub-router). The networking configuration page looks at the overall situation.: Whether the sub-router is in the network and whether the backhaul is wired or wireless. But what is really useful for "Which phone should I connect to?" Topology map ： The main router and the sub-router are drawn as two nodes, connected by a line, and the connection line is marked with wireless or wired (if a network cable is plugged in and used for wired return, the connection will change from the wireless mark to the network cable mark). When I was setting up the network, I confirmed the backhaul status on this picture. These basic cognitions are in Mesh networking sequence article I’ve written it before, so I won’t repeat it.

But there is a blind spot in the topology map that needs to be explained in advance.: It draws the relationship between routers, not where the mobile phone is. . The two machines in the picture are well connected, but you still don't know who is holding the phone at the moment. And I found a more troublesome pitfall in my actual measurement - which node a certain device is connected to. I rummaged through the router plug-in of the Mijia App, and the information given was quite limited.: The device list is for the whole house (summarized from the perspective of the main router), and there is no "group by node" view. I later read other people’s Mesh reviews on What’s Worth Buying, and the reviewers also came to the same conclusion.: Mijia "cannot see which terminal devices are connected under the main router and node router." This is an old problem of this App. The new firmware has enhanced some of it, but there is still no direct answer in the App regarding the granularity of "which phone is connected to it at the moment?"

Therefore, in Mijia App, the correct usage of topology map is two steps.: First confirm that the sub-router itself is online and the return journey is normal. (If the sub-router goes offline, it will disappear directly from the topology map. That is another fault. Go away. The article about troubleshooting the sub-router without network connection way) ； Then go to the device list and click on the phone you suspect to see its real-time information. The only thing I could confirm that night at Mi's house was: The sub-router is online, the backhaul wireless, and there are two signals - so far, I don’t know which one the mobile phone is connected to.

Second stop: 31.1 The "complete network menu" in the background of the web page is one more level than what the App provides.

mobile browser 192.168.31.1 (or miwifi.com ), log in to the web backend with the management password. Many people find this step troublesome, but many of the advanced functions of Xiaomi routers are only in the web backend, while the Mijia App takes care of another layer of work. I have gone through the backend menus one by one before for this division of labor. The article written on 31.1 Backstage Panorama inside. The entry related to the judgment node is: "View full network menu" in the upper left corner of the home page」 .

After clicking in, the interface will spread out the overall status of the Mesh network.: There is one entry for each router, including the main router AX6S and the sub-router AX3000. The key function is Each router can be clicked in individually. ——For pip routing, go to the sub-routing's own management page (you will be asked for a management password again), where you can see its own status.: WiFi name, frequency band, and what's in its name. That's what I did that night: Go to the page of the sub-router AX3000 and want to see if the mobile phone in the master bedroom is under its name. ； Go back to the main router page to compare. With a pair of information on both sides, you can spell out "Whose name is the mobile phone under?"

This method is usable, but the experience is a bit rough to be honest. One is verified by my actual measurement and subsequent reviews by others.: The terminal information under the node name in the background of the web page is incomplete. ——When I clicked on AX3000, I could see that there was a terminal connected, but the interface was vague about which phone it was and what its name was. I had to cross-check "connected frequency band + online time" with the main router list. Another is that you have to re-enter the management password every time you enter a router, which is very annoying when switching back and forth. There is another prerequisite: Your phone must be connected to your home WiFi to open 31.1 ——If you are at work and want to check your home, this route will not work. You have to go back to the remote mode of Mijia App, which will return you to the blind spot of the first stop.

Third stop: Netsh looks at the BSSID, a clumsy way but the final word

The first two stations only gave "indirect evidence", but the last one was solid evidence. One word of principle: The name of WiFi is SSID, and the whole house Mesh shares one SSID, but Each physical router has its own independent identity number under the same name, called BSSID. ——Which one the mobile phone is connected to is essentially the BSSID it is connected to. If you want to know who your mobile phone is connected to at the moment, find out its BSSID and pair it with the BSSIDs of the two routers at home, and the answer will come out.

The most convenient tool for checking BSSID is a computer: Connect your Windows laptop to your home WiFi, open the command prompt, and type a line netsh wlan show interfaces , there is a line of "BSSID" in the output, followed by six groups of colon-separated hexadecimal numbers, which is the currently connected machine. How to distinguish BSSID from SSID, how to read the output of this command line by line, I have done this before BSSID popular science article Li Zhan wrote ； How to check the path on Android other than Windows (after Android 10, the system hides this entrance deeply, making iOS even more troublesome). Where do the BSSIDs of the two routers come from? 31.1 Go to the main router and sub-router pages in the background. You can see their respective wireless parameters on the wireless status screen. ； If you really can't find it, there is a simple way to do it - stand in front of the main router with your mobile phone and take a look at the BSSID and write it down, then stand in front of the sub-router and take a look, and you will have both numbers.

This method is stupid, but it has two advantages that cannot be compared with the first two stops. One is The evidence is direct ： The first two stations are "The router tells you who owns the phone", and this is "The phone tells you personally who I am connected to." If the two ends don't match up (this is the case, the router list will be refreshed half a beat later), believe this. The second is Can see changes ： That night I walked from the master bedroom to the living room and back with my laptop, typing commands every few steps, and saw with my own eyes that the BSSID was translated from the number of the sub-router to the number of the main router, and then back again - the path of the mobile phone switching and the locations where it hesitated were all recorded. This is how the truth about that night in my master bedroom was nailed down.: During the mosaic period, the BSSID has always been the number of the main router, and the mobile phone has not been able to access the sub-router across the wall, which is typical of stickiness.

How to adjust after checking: Three gears to choose according to your condition

It was clear that I had connected to the wrong person. The next steps were divided into three levels according to the severity of the condition. I tried them one by one from mild to severe.

First gear, Don’t move the setting, move the position . The root cause of the stickiness is that the mobile phone feels that the main router signal is "just okay" and not worth switching. Move the sub-router closer to the active area of ​​​​the mobile phone, so that the signal advantage of the sub-router is so great that the mobile phone cannot ignore it, and many minor illnesses will be cured on their own. I have gone through a complete pitfall in the networking article about the relationship between sub-routing placement and signal switching, so I won’t go into details here. That night, I moved the AX3000 from the top of the bookshelf in the master bedroom to the height of the bedside table. The frequency of mosaics was visibly reduced, but it has not been eliminated.

Second gear, Unpopular switches hidden in Mijia App: Specify the connection node for the device . This is the biggest unexpected result of this research. Xiaomi has provided a "device connects to the specified Mesh access point" type function in the Mijia App (the entrance is in the page related to device details, set according to device granularity): After multiple routers are grouped into a Mesh, the nodes connected to some devices are not optimal. Manually specify a device to be permanently connected to a router . It is equivalent to bypassing the stickiness of the mobile phone and making decisions for it. After I assigned the mobile phone in the master bedroom to the AX3000, the mosaic was removed that night. The price is also straightforward: This mobile phone is nailed to the sub-router. If you carry it to the living room one day, it will most likely stick to the sub-router until the signal is lost. Designated connection and automatic roaming are contradictory, and are only suitable for devices that "reside in one room" (TV box in the master bedroom, wireless network card on the desktop). Don't use this trick on mobile phones that travel everywhere. Using this trick is equivalent to using stickiness in reverse.

Third gear, Return journey . If it is determined that the phone is clearly connected to a sub-router but still stuck, the problem lies in the leg of the sub-router that returns to the main router.: If the wireless backhaul signal is weak, use a router or switch to a power modem. ； If you have pre-embedded network cables at home, you can directly plug in the network cable and take the wired return trip, which is done in one step. The WAN port of the network cable plug router is not the LAN port. If you plug it in incorrectly, it will treat itself as an independent router and change the second floor to a new network segment. I have stepped through this pitfall. There is a picture in the networking article. Another thing to mention, to judge "whether the signal of the node connected to the mobile phone is good or not", don't look at the cell phone number, go to the background to read the signal strength dBm value of that device, -60 and -74 are two different worlds, how to read the reading Signal strength interpretation article A comparison table is given here.

Ending with a table: Symptoms, diagnosis, and prescriptions are aligned

From beginning to end that night, I spent more time on "judging" than "adjusting" - which is why I wrote this article. There are a lot of tutorials on Mesh networking online, but there are very few that talk about "how to know who is connected after the group is completed." Put my process this night into a table:

End with a truth: There is no fast and accurate official channel to determine the node. Xiaomi spreads the information in three places (App topology, web background, device system information), giving each a corner, and putting it together gives a complete picture. It's a bit of a toss-up, but it's better than guessing at a full grid of icons - if I hadn't checked the BSSID that night, I would have probably reset the sub-routing, and it would have been a waste of effort all night and it still couldn't cure the disease. Judgment first, then adjustment, don’t worry about this order.