2.5Gb LAN ports not communicating (GL.iNet MT6000 and Linksys SPXNMP56)

Installing and Using OpenWrt
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Issue: I'm experiencing a connection problem between my MT6000 router and SPXNMP56 switch when both are using their 2.5Gbe ports.

Details:

  • The connection works fine when using a 1Gb port on either device and the 2.5Gbe port on the other device.
  • However, when both devices are connected via their 2.5Gbe ports, the connection fails to establish completely. There's no fallback to 1Gbps.

Why is the connection failing only when both devices use their 2.5Gbe ports? Could this be a compatibility issue, a configuration problem, or something else? Any help would be greatly appreciated!

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Try another cable

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Yes I've tried several, and also tried on another identical access point. I don't see how the cable would be the issue as it works fine in 1Gbps.

4

cable rated for 1gbit doesn't work at 2.5gbit ?

I've had old cat5 (not even 5e) cables behaving like that.

5

The cables don't work at all. Thre's no negotiation, and the cables I've tried are all CAT6A or CAT6 (10Gbps). I never said they were rated at 1Gbps. Sorry if I didn't make that clear.

6

you could try disabling autoneg using ethtool (or mii-tool if it's a RTL chip), and forcing 2.5gbit port speed.

7

Can tihs be done somewhere in OpenWRT/Luci? I wish I had another device to test that supports > 2.5Gb, but I do not sadly.

8

Ethtool is a cli tool, don't think you can force the port speed using LuCI.

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enable nat hardware offloading

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image1094×689 25.3 KB

the cpu gets overloaded without it

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10

Are you using the 2.5 gig wan or the 2.5 wan/lan, you need to use the later

With a fresh install of openwrt the wan/lan works as a lan, that is unless you changed some settings

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Sorry for the delay in getting back to you all on this.

After some pretty extensive testing, I'm fairly certain it's a driver/kernel mismatch causing the problem on the Access Points.

  • ethtool Clarity: ethtool proved to be invaluable! I used it to check the LAN1 port on my Flint 2, and it's definitely behaving as it should. No issues there.
  • Stock Firmware Test: To rule out hardware issues, I flashed one of my APs with the stock firmware (remember, I'm using an unofficial OpenWRT build) and It worked perfectly fine.

So, it's highly likely a mismatch between the OpenWRT drivers/kernel and the AP hardware of some kind.

Thanks everyone for your suggestions! I will mark this post as solved.

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So the solution is what ?

It's currently b0rked, beyond repair ?

:slight_smile:

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:rofl: I guess it's not a solution per se, but more-like I know what the cause is. There isn't actually a fault with the router or the APs, as stock firmware is fine. The SXNMP56 routers/APs have only recently supported OpenWRT and no doubt future builds will (hopefully) get to the bottom of this issue.

I didn't want to just abandon this post as there's nothing worse when you're searching for help, only to read all posts in a thread and then it goes to nothing.

I've posted a lot more details on the main thread here

Thanks!

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