GS310TP - Autonegotiation on g8 to 100FD with a 1000FD capable cable and device

[MirceaDamian]

Hi,

To my shame (after probably 4 months operating like that) I have noticed that a port (g8) is negotiating 100FD towards a device which happens to be the Router of my home WiFi mesh system (another brand which has a WAN of 2.5GbE and 3 LAN ports of 1GbE out of which 1 is connect in this switch on this port g8). My ISP is delivering me 250Mbps capacity so a limit to 100FD is not desirable.

That did not ring any alarm bells since you hardly need more than 100Mbps on your WiFi devices and the Router of the mesh system has its own WiFi area where devices could get the full speed and frankly I never bothered to run some speedtests on some of the wired devices which would have quickly uncovered the limitation.

Though yesterday I have run into some problems with the WiFi mesh system after a software upgrade which triggered my attention to look into the connectivity. I have discovered this 100FD connection and I thought it was a problem related to the software upgrade so I have quickly decided to rollback. Still the problem did not resolve.

The connection between the Router and the switch is through a Cat7 SFTP cable patched into a Cat6a wallplate and a Cat6a cable with Cat 8.1 connectors.

The connection between the Router and the ISP device is following a very similar path and it works both at 1000FD as well as 2500FD.

After several attempts of restarts and tweaks both on the Router and the switch I thought about simply moving the cable from g8 to g6 and to my surprise in g6 it works at 1000FD without any problems.

Here is a snippet of the config, as you can see there is nothing special about the port config, everything is on default setting:

interface g6
 description "1st Floor ZenWiFi"
!
interface g7
 description "Camera DCS-5222LB1"
!
interface g8
!

Maybe something to note is that g7 is 100FD (and it should be so because that Camera has a 100GbE interface). Is that having some influence on g8?

I'm really confused of what is going on here but I have two ideas to investigate further:

1. Upgrade the software on GS310TP (currently running 1.0.0.12).

2. Try another device capable on 1000FD into g8 and see if there is a particular interoperability issue between the Router and the switch (though the fact that it works on g6 at 1000FD would make this very strange).

So I thought about asking here if anyone has encounterred something similar or has any other bright ideas.

Thank you

Mircea

[MirceaDamian · Accepted solution]

Ok, so just to conclude on this topic for anyone who might read it latter.

I did a software upgrade to 1.0.1.2 and tried again with my MacBook and the 10GbE adapter and now I'm getting consistently 1000FD.

My guess is that something got in a strange state and the upgrade fixed that. I have tried to plug/un-plug the cable multiple times and everytime it worked as expected (auto negotiation at 1000FD).

[schumaku]

If other ports are reliably negotiate to GbE and just this g8 does have an issue, it might be small hardware issue.

In general, most problems speed negotiation are caused by cabling and wiring

[MirceaDamian]

Just to rule that out I have just done a test with a 3m patchcord connected to my 10GbE USB-C transciever to a MacBook pro.

I've got 1000FD on all ports of the switch except g8 which reliably stays at 100FD.

So I'm leaning towards a small hardware issue idea as well.

I will do the software upgrade as well just to be sure and if things look the same I will probably ask for RMA.

[MirceaDamian · Accepted solution]

Ok, so just to conclude on this topic for anyone who might read it latter.

I did a software upgrade to 1.0.1.2 and tried again with my MacBook and the 10GbE adapter and now I'm getting consistently 1000FD.

My guess is that something got in a strange state and the upgrade fixed that. I have tried to plug/un-plug the cable multiple times and everytime it worked as expected (auto negotiation at 1000FD).