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replikant
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Help configuring (sub)network using CRS305-1G-4S+IN

Thu Mar 25, 2021 9:36 pm

Hi,
I know very little about networking, so bear with me. I currently have AT&T internet with an ARRIS BGW210-700 as my primary gateway and router. I have several 1Gbs devices plugged directly into the AT&T router including an Eero for WiFi and another 1Gbs switch with additional devices connected to it. My goal is to connect the CRS305 to the 1Gbs switch and have all the computers attached to the CRS communicate at 10Gbs while still being able to communicate with the other 1Gbs devices and access the Internet.

So far I have found some seemingly similar questions/answers on these message boards and on the broader web. However, they are either just different enough that I can't make the solutions work and/or I don't understand to translate what I've found into the settings on the ARRIS and CRS. So, I still haven't been able setup the network properly. The computers connected to the CRS still only communicate at 1Gbs presumably because they are routed through the ARRIS.

Any help is greatly appreciated.

Edit:
Here's a rough diagram of what I am trying to setup:
                             Internet
                                |
                            AT&T Router
                                |
        -----------------------------------------------
        |                       |                     |
   Eero (bridge)        Some other devices       1 Gb/s Switch
                                                      |
                                           -----------------------
                                           |                     |
                                       Computer A          Mikrotik CRS305
                                                                 |
                                                  -------------------------------
                                                  |              |              |
                                            Computer B       Computer C      Computer D
 
replikant
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Re: Help configuring (sub)network using CRS305-1G-4S+IN

Sat Apr 03, 2021 9:02 pm

It turns out I am probably making things more complicated than they need to be and I probably do not need subnets or anything complicated. The original problem was probably due to a bad connection. Either a bad 10GBase-T transceiver, bad Ethernet cable, or flakey network card. However, I am still having trouble getting my computers all communicating at 10Gbs speeds and would appreciate help.

In the diagram in the previous post Computer B and Computer C have Mellonox Connectx-2 SFP+ NICs and connect to the switch using DAC cables. Computer D has a NIC with an RJ45 port and connects to the switch via a transceiver. Due to physical constraints in my location using an RJ45 connection is basically required for this computer. B and C can talk to each other at 10Gbs speed but D talks to B and C at 1Gbs.

A short 18in ethernet cable connects the switch to a jack in the wall. There is a roughly 10ft cable that runs under the floor to another jack and then another 18in cable from the jack to the network card. All the cables are cat6. I realize cat6a would be better, but I would think at such short distances cat6 should still work.

I have tried running a cat6a cable directly from the switch to the computer and I have tried 2 different 10Gbs network cards (an Intel x540 and an Asus XG-C100C, but the best I can ever get is a 1Gbs connection between D and B (or C). I have also tried manually specifying the connection speed with ethtool, but anything other than 1Gbs fails and will not connect.

Is this a limitation of this type of network card? If not what is the likely culprit, what are my next trouble shooting steps, and what else can I do?

Any help is appreciated.
 
replikant
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Re: Help configuring (sub)network using CRS305-1G-4S+IN

Tue Apr 06, 2021 1:36 am

For anyone that stumbles upon this thread with a seemingly similar problem. I'm not sure what I did, but everything is now working (mostly). I have now established a 10Gbs connection between all pairs of computers connected to the Mikrotik switch. However, I suspect at least one of the components (the transceiver maybe) must be flakey. Even though I have made a connection, it will occasionally drop out and I will completely lose the connection (not just dropped frames or lower speed).

I guess I'll try a different transceiver at some point to see if that resolves the issue, but no complex subnets or vlans were ever needed.

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