Two identical AC86U in Router and Mediabridge slow ?

[robs]

Hello,

I have two AC86U with Merlin 386.2_6, one is in Router Mode and the other in Bridge Mode.

I have a Fiber connection that goes up to 750-780Mbits in download speed. QOS is off

I tried this second AC86U in media bridge mode over 5Ghz, and while it says Link Rate: 1950Mbps, the download test via ethernet cable (to the media bridge) doesn't go past 400Mbps
To do the test, the two routers are no more than 50cm distant each other.

Any reason why I don't get full gigabit speed ?
The same test with the same computer and the same cable attached to the device in Router Mode gives around 700Mbps

I attach a screenshot, sorry for the Italian language in the UI

Thank you,
Roberto

 

[L&LD]

You're expecting something that will never happen. Particularly with the two routers 50cm apart (that is way too close to each other).

It's not clear to me how the devices are connected and how you're testing either. What is the client device you're using to test with? Where are you downloading from?

 

[robs]

You're expecting something that will never happen. Particularly with the two routers 50cm apart (that is way too close to each other).

It's not clear to me how the devices are connected and how you're testing either. What is the client device you're using to test with? Where are you downloading from?

Hi,
The test setup is as follow:
Laptop -> ethernet cable (gigabit) -> MediaBridge : ookla speedtest result via command line is 400Mbps
Laptop -> ethernet cable (gigabit) -> Master Router: ookla speedtest result via command line is 700-750Mbps

The speedtest is always run against the same internet server (I have Wind as ftth provider so the server is Wind - Milan)

Master router is connected via WAN to a media converter that is connected to the physical fiber cable (pppoe connection, very stable)
MediaBridge router is connected physically only to the laptop via ethernet cable, on the wireless side it's connected to the master router on the 5Ghz band in Bridge Mode (Everything set to Auto on the master for the 5Ghz, anyway it currently shows 80Mhz Channel 44/80 that is free)

I also went some meters apart for the distance between the two routers, the result is less speed

If the link rate in the mediabridge is 1950Mbps as the screenshot shows, shouldn't I get at least the full 700Mbps of my WAN fiber connection ?

Thank you,
Roberto

 

[L&LD]

Do you have many AP's around your home? Is the Wi-Fi airspace congested?

See if the following suggestions help you get a faster speed.

About L&LD

Specifically the recommended defaults in the M&M Config guide, and the Control Channel setup guides.

 

[robs]

In the 5Ghz band it is quite free, 2.4 is congested instead

I followed your guide, I can't get more than 450Mbps at 2-3 meters open space

Tomorrow I will try changing the channels manually.

In your opinion, with this setup should I get the full bandwidth ?

Thank you,
Roberto

 

[JGrana]

Since the rate your master router is getting from the WAN is 700 Mbits, I'm not surprised your getting less over Media Bridge mode. The rate is already at 700 Mbits by the time it gets past TCP/IP and packet processing/routing.
The WiFi link rate has even more overhead than ethernet links. Lots of small control packets flowing over WiFi between router and clients (Media Bridge is a client). All the time...

 

[robs]

Since the rate your master router is getting from the WAN is 700 Mbits, I'm not surprised your getting less over Media Bridge mode. The rate is already at 700 Mbits by the time it gets past TCP/IP and packet processing/routing.
The WiFi link rate has even more overhead than ethernet links. Lots of small control packets flowing over WiFi between router and clients (Media Bridge is a client). All the time...

I understand what you say but we are talking about 300mbits of overhead, or 40-45%

From a networking point of view that's not the way it should work, maybe I can try a factory reset tomorrow

 

[JGrana]

Agreed that under 50% is quite a hit. Given what I have read on wifi link rate versus data rate, 70% or more would be a reasonable goal.

 

[Hunny Puppy]

Hello,

I have two AC86U with Merlin 386.2_6, one is in Router Mode and the other in Bridge Mode.

I have a Fiber connection that goes up to 750-780Mbits in download speed. QOS is off

I tried this second AC86U in media bridge mode over 5Ghz, and while it says Link Rate: 1950Mbps, the download test via ethernet cable (to the media bridge) doesn't go past 400Mbps
To do the test, the two routers are no more than 50cm distant each other.

Any reason why I don't get full gigabit speed ?
The same test with the same computer and the same cable attached to the device in Router Mode gives around 700Mbps

I attach a screenshot, sorry for the Italian language in the UI

Thank you,
Roberto

Did you every figure this out? I’m having a similar issue. I put my RT-AC86U in media bridge mode with my RT-AX88U. But the most I can get out of 5GhZ connection on channel 149 80Mhz wide is about 250mbps, while the link rate shows about 1700mbps. That sucks! I was getting higher speeds when the AC86u was in router mode but in media bridge it’s crawling.

Any suggestions, I would like to get atleast 800Mbps from it. I’m able to get this from other AC client on the network so I know the airspace isn’t a problem.

 

[Hunny Puppy]

If this helps anyone, I figured out what was going on. My testing was being done using a file transfer over windows SMB. That is a terribly designed protocol with a lot of back n forth which is horrible in a WiFi environment because WiFi is half duplex (unlike wired Ethernet which is full duplex). So because of the back n forth and held duplex nature it was clogging up the network (where as a full duplex Ethernet can freely go back n forth simultaneously).
I redid the test using UDP and iPerf so I don’t run into the half duplex issues on WiFi (ie one way communication) and I got a full 1GBps out of the network. Every with a TCP iPerf test (some back n forth) I still got 700mbps from it (on a 1600mbps link). Basically Windows file sharing sucks for WiFi.