Where to change the LAN port speed of Mercury Tenda router? Gigabit broadband speed test card 94M, 90% of it is a 100M port router blocked in the middle

A colleague's Gigabit broadband was purchased last year, and the speed test has been stuck at around 94M for half a year. He called the operator three times, the technician came to the door twice, the optical modem was replaced, and the broadband account was reset once, but it didn't work. Last weekend he brought a Mercury D121G to my house and said, "Please help me see if this machine is broken." I didn’t check the settings first. I first looked at the label on the back of the machine, then went into the backend and clicked on the network port status to check it again - the problem was found, and it has nothing to do with broadband.: His D121G is a 100Mbps machine. The four LAN ports and one WAN port are all 100Mbps. The Gigabit broadband connected to it is like connecting a four-lane highway to a rural road. The exit is only 100Mbps. If you divide it by 8 and then deduct the protocol overhead, it is not capped at 94M.

The most embarrassing part about this is that: You can't tell the appearance of a 100M port machine at all. There should be a few antennas, the lights should be flashing, and even the WiFi is normal. Today, I will write down clearly how Mercury and Tenda check the network port speed, which popular models have 100M ports, and whether the LAN port speed can be changed in the background. The Gigabit broadband speed test at home is labeled 94M. First check the router queue according to this article, and don’t let the operator’s technicians run in vain.

Let’s figure out a rule first: The LAN port speed of Mercury and Tenda cannot be changed in the background.

Let’s say the most unpleasant things to the front first, so that you don’t go through the backstage in vain.: Home machines from Mercury and Tenda, The LAN port speed is not switched in the background . I flipped through the settings pages of D191G, D268G, AC10, and AX12, and clicked on "Advanced Settings", "Routing Settings" and "System Tools" one by one. Some firmwares on the WAN port can also choose to auto-negotiate or manually specify the speed. There are no speed options on the LAN port. The reason is simple: The speed of the LAN port is the network port chip welded to the motherboard. The 100M port is the 100M PHY chip. Software cannot change the hardware. This is not because the firmware is unkind, but because it cannot be changed physically.

So there are only two things left that can be done in the background: First, go to the status page to see the currently negotiated rate of each LAN port and confirm whether it is really only 100Mbps. ； Second, if the WAN port is also 100M, some models can manually specify the speed mode, but that only changes the negotiation method. The upper limit of the chip is still 100M, and it cannot be changed to Gigabit.

I guess someone wants to ask, why can a bunch of tutorials be found online when searching for "LAN port speed setting"? Because most of those tutorials are written about TP-LINK or ASUS. Some models do have port speed options in the "routing settings" of the new TP-LINK firmware, and the ASUS backend can even detail each port. Mercury Tengda and Mercury Tengda are empty of this function. I followed TP-LINK's tutorial and searched the Mercury backend, but I couldn't find it even in the middle of the night. This is not your cup of tea, and it doesn't exist at all.

Where can I check whether my machine has a 100M port or a Gigabit port?: three roads

The search methods are sorted according to the degree of ease of use, and each one is more accurate than the last one.

The first way is to look at the packaging box or the official website parameter page. Mercury with a "G" suffix after the model, such as D191G, D268G, D121G (this is a special case, discussed separately below), the old rule is the Gigabit version with G, and the 100M version without G. But this rule has been disrupted by Mercury itself in the past two years. Although the D121G has G, it is actually a 100M port machine. The parameter page clearly states "10/100Mbps adaptive". Therefore, the parameter page on the official website is more reliable than the model name. Go to Mercury's official website to search for the model number, turn to the "Interface" column, and see if it says 10/100M or 10/100/1000M. This will not fool anyone.

The second way is to enter the background to check the negotiation speed. Mercury enters 192.168.0.1 or melogin.cn , Tengdajin 192.168.0.1 or tendawifi.com , after logging in, look for "Device Management" or "Running Status" and click on the status details of each LAN port. When the computer is plugged into the network cable, the negotiated speed line says 100M. Don’t jump to conclusions yet. The network card of the computer must be Gigabit and the cable must be eight-core, otherwise the computer will be a drag. Take a computer that is sure to be Gigabit and a line that is sure to be eight-core. If you plug it in and it is still 100M, then this port is a 100M port, for sure.

The third way is the stupidest but the most accurate: Look at the lights. Many models of Mercury and Tenda models do not have speed lights next to the network ports, so there is nothing you can do, skip this one. For machines with a speed light, plug in a Gigabit device and an eight-core cable. The speed light will be green (Gigabit) and orange for 100M. Both companies have lamp language tables in their manuals. I used to know the rules for Mercury’s SYS lamps. Indicator light meaning As written in that article, the same principle applies to network port lights.

By the way, I can’t tell what the two backend interfaces of Mercury look like. Let’s look at what I wrote first. Comparison of menus between old and new Mercury interfaces Scroll down further, otherwise it will be easy to not find it in the new interface.

These popular models are 100M ports, so they are right on the mark.

I went through the parameters on the official website and added the machines I have used myself, and listed the ones that readers on the site asked about the most. To explain before: Mercury Tenda models iterate quickly, and the network ports of different hardware versions of the same model may be different. Before buying, you must refer to the current parameter page of the official website. This table should be used as a starting point.

Intuitive conclusion from looking at the table: There are many 100M port machines hidden in Mercury's 100-yuan old D series models, but Tenda's AX series on sale basically don't have this pitfall. For models with a G in the suffix, take a look at the official website parameters before placing an order. Counter-examples like the D121G that “have a G but are 100 Mbit/s” are lessons to be learned. If you want to know what hardware version you have and where to check the parameters, check out my previous How to check the model and hardware version , stickers, backend, and App are all available.

The most sinister tipping position of a 100M port router: Repurposed as a switch

The most unfair scenario is that Gigabit broadband is equipped with a 100M port: Gigabit routers are good. In order to save network ports, someone connected the retired old Tenda FH456 at home to the main router and used it as a switch. The desktop computer and NAS were all plugged into this old machine, and the speed measured was all at 94M. I thought there was something wrong with the main router.

In this connection method, each LAN port on the old router is a 100M port, and the speed of data passing through it is limited. It has nothing to do with how powerful the main router is. Moreover, when using an old router as a switch, you have to manually turn off DHCP and change the LAN port IP to avoid colliding with the main router. These two steps themselves have a lot of details. I wrote a special article about the overturning posture before. How to set up a router when used as a switch Don’t skip the order in that article.

It’s easy to tell whether it’s a trap like this.: The devices with slow speed measurement are all plugged into the secondary router, and the devices plugged into the main router are all normal. It is basically a problem with the network port or settings of the secondary router. On the contrary, all devices are slow, check the main router and optical modem. This idea and investigation Internet speed dropped to 93 MB That article is of the same lineage: First draw the link diagram, and then check the speed one by one. The number 94M itself is the signature of the 100M link.

WAN port speed line: Don’t let go of the parts that can be changed.

Just because the LAN port cannot be changed does not mean that the entire machine cannot be saved. If your Mercury or Tenda is a Gigabit port machine and the speed test is still 94M, then the problem is probably in the link negotiation. Some machines can intervene in this part in the background.

Mercury's side: Enter 192.168.0.1 , "Routing Settings" → "Internet Settings", scroll to the bottom of the page and go to "Advanced Settings" or "WAN Port Advanced Parameters". Some firmwares have a "WAN Port Speed" or "Connection Mode" drop-down box. You can choose automatic negotiation or manual specification. Tenda here: tendawifi.com Go to the backend, and some models also have similar options in "Internet Settings". The old AC10 is hidden in "System Management". The two names are not consistent. Look for the words "WAN port speed", "port speed" and "connection mode".

But go through other checkpoints before manually specifying them. If you do it in the wrong order, it will be in vain.: First make sure that the optical modem is plugged into a Gigabit port and not an IPTV port. I wrote this in How to distinguish between optical modem Gigabit port and 100M port inside ； Make sure that the cable from the optical modem to the router is eight-core CAT5E or above. The four-core cable can only run at 100Mbps. ； After confirming these two levels, it's the backend's turn to negotiate. The order of these checkpoints is something I worked out along the way when I was helping my colleagues to troubleshoot. It is also related to the speed measurement posture. Only wired measurement is accurate. That method is How to measure broadband speed accurately There is.

By the way, the background status page is the eye of the entire investigation. You can see the WAN port negotiation rate and connection duration on the status page of Mercury Tenda. If you don’t understand those fields, please turn to How to view the running status page , recognize the six fields one by one.

An account that cannot be changed: Calculate this before changing the machine

After the investigation has reached this point, if the machine itself has a 100M port, there is no setting that can save it. The only two options are to change it or tolerate it. I did this calculation for my colleagues, and it was easy.

For broadband 100M and below, the 100M port is not wasted at all. Just keep the machine if it can be used, don't bother with it. For broadband from 200M to 1000M, the 100M port machine is the bottleneck, and replacing it with a Gigabit port machine is the only solution. An all-gigabit entry-level machine like the Mercury D191G can be purchased for just over a hundred yuan. ； WiFi6 models like Tenda AX12 are priced at 200 yuan. A colleague spent 109 yuan to replace a D191G and plugged in a 472M test. His anger for half a year disappeared.

Don't believe those "Gigabit router" headlines on second-hand platforms. The Gigabit 90% mentioned by sellers refers to the WiFi speed, and the network ports are 100Mbps all over the place. This pitfall is similar to what was written on the site. The speed difference between the two mobile phones is more than 100 megabits Is a fellow student: The difference of one word in the parameter list is ten times the difference in actual speed. When buying a new machine, make sure the parameter page says 10/100/1000M. The first thing you do when you receive the product is plug in a gigabit device and check the negotiated speed. Do not wait until WiFi is connected before receiving the product.

Ending. Mercury Tenda's LAN port speed cannot be changed in the background. This is a matter of hardware level. ； What you can do is to identify it on the status page, avoid pitfalls in the model table, and clean up the WAN port negotiation and link gates. The number 94M appears in Gigabit broadband homes. First check the router network port, and then call the operator. The reverse sequence is a waste of time. The lesson learned by my colleagues who made three phone calls and two short-term calls in half a year should be saved for everyone.