Question D-Link DGS105 Drops from 1Gbps to 100Mbps

KreachersHell

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Nov 19, 2014
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Hey guys,
Long story short I bought a D-Link DGS105 switch and for whatever reason it drops internet connection from full speed then reconnects to the limited 100Mbps. It sometimes can run a speed test just fine and other times it won't as well as internet browsing.

I have Shaw Internet Fibre 750+. Directly connected to the modem I receive about 820Mbps. I was having issues with the TP-Link Archer C7 AC1750 where it the limiting factor for a bit. Sorted that out and now from modem (in bridge mode) to router to PC I was getting almost 800Mbps at a slower gradual climb. Now connected from modem to router to switch I can hold about 800Mbps for what seems to be a limited amount of time before it decides to crash my connection and lower to 100Mbps connection. The switch is connected to my wife and I's PC's, however hers is never really on while the disconnects happen. Any Ideas ? Did I happen on a bad switch?

Side note. When I first set it up it would crash on every speed test until I left it alone overnight. To which it became more stable but now it crashes intermittently.

Edit: Sorry forgot to mention all the cables are Cat5e and Cat 6. and I have ruled them all out as not a contributing factor by switching them around. (as far as I can tell)
 
It has to be a cable issue. The only other thing would be defective ports and that is highly unlikely. It is even more unlikely since it is multiple ports and you have the same issue both on your router and switch.

First make sure all your pc have the nic setting on auto. The router and switch only run in auto and a PC must match to work properly.

There are really no setting or anything you can change especially when you have a unmanged switch. There were some devices that have some garbage energy saver stuff that causes issues but I don't think your devices do.

Luckly your switch has indicator lights that show which ports are running at gigabit and 100m. This should make it easier to tell which connection is dropping to 100m. I have not looked up your router but some routers you can also tell by the lights. Many routers also have status screens that show the port speed.

This is purely a matter of finding the offending cable.

It would be really nice if when a cable was bad it would just not work at all. They tend to be very strange and work on some devices and not others and sometimes they work for a while and then don't. It many times is something like a wire that is slightly loose and as the heat and cool the connection will change.

It tends to not be worth the effort to replace the ends on bad cables unless they are very long cables.

Be aware there are massive amounts of fake cable on the market. You need to be sure your wires are pure copper (no CCA) and have wire size 22-24 (no flat or thin cables). The fake cables do not meet the certification standards and "CATx" is just a name and not a actual certification so the fakes can use that word and not get into trouble.
 

KreachersHell

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Nov 19, 2014
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Sorry for the very late reply and thank you for your very quick reply. I usually only have weekends to deal with the problems at hand.

I've done some more trouble shooting here and there and although I was still not achieving our accredited 750+ speeds they were a manageable 500-600 range. However trying to game with the wife the last couple days has proved to be very frustrating. When we are both online gaming and in a discord with friends we would both occasionally get kicked from games at the same time and our discord chat would hit 5000 ping and we couldn't broadcast our voices (only receive audio) which has worked several years prior with no issues. We gave up eventually after repeated events.

I have swapped many cables to my dismay I don't believe they are the culprits. As you mentioned I do have some of the flat cables so I have ordered some replacement 24 gauge copper cables anyways. I ruled them out by basically running different cables from modem to pc directly and I was able to get max speeds + on all cables.

I am quite defeated... It appears the router is back at being a limiting factor so I can't even test to see if the switch is still crashing. Since a few days after my first post it appears that the connections on the switch stay green indicating above 100mbps connection.

Connecting modem to router to pc (no switch in this set up) I only receive 230mbps now. Sometimes it will slowly drop to below 40mbps... Which is where I think we both end up getting high ping and booted from games. I've tried disabling NAT boost and using QoS settings on and off. Thats kind of another topic I've been running through looking for help. Once I get this figured out I can get back to the switch.
 
Reset the router to factory settings. Only set the admin and wifi passwords. The NAT boost thing should be on by default and that is a very key feature to get high data rates. It allows traffic to bypass the cpu for NAT. Without this all the traffic must be processed by the cpu and even the fastest routers only get 250-300mbps.
Just tuning on some feature like QoS will disable this feature because the CPU needs to see the data and you will be bottlenecked by its ability.

This likely does not explain the problems you are having. It may run slower with the CPU but you should not have delays and drops unless you are attempting to pass 300mbps of traffic at the same time.

I would check if there is newer firmware for the router and maybe you get lucky it is a bug. Otherwise I would be considering a new router.
 

KreachersHell

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Nov 19, 2014
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Router has been factory reset now and the firmware was already up to date.
Running a speed test after reset (modem - router - pc) resulted in a decent increase to 600mbps.
Still not quite the 820 but could definitely live with that. However if I throw the switch into the mix, as one could presume it cuts it in half for both pcs. My pc on and hers off but all connected to the switch I resulted with near 300mbps. Finally running a test on both pcs at the same time knocked us both to about 100-150mbps. Now yesterday while testing her pc would take priority and go up to 280mbps and mine would drop to 30mbps.. so fortunately it doesn't appear to favor a connection this time around.
I understand as more things are implemented into the network that there's decreases in speeds. But is it generally that significant? To go from a modem connection speed of 820 to a hopeful 100+?
I might be looking into a managed switch and a possible new gigabit router.
Unfortunately with our layout we cannot just connect both pcs to the modem directly.
This house has built in ethernet cables. The hub is in the garage (where the coaxial hook up is). There is only one wall cable that goes up to the 3rd floor where the two pcs are. Hence why I need a switch and or router. Originally I bought the router and had it installed upstairs where I split the connection from the modem (wall port) to both pcs stable and fine. We had other issues where our tv downstairs wouldn't let us cast as it wasn't on the same network as our phones (since it was wired to modem and phones were on router wifi). Putting the router down with the modem allows all our wifi and networking to be on the same network as well as being more secure. So we introduced a switch to enable both pcs to have wired connection again and we upgraded our internet to shaw fiber+750 (which comes with a new modem of course). Ever since the router went downstairs nothings worked again.
 
A switch is so simple it would be unlikely it is the problem.

So if you connect directly to the cable that goes to the router you get 600 but if you plug the switch in and then plug your pc into the switch and nothing else you only get 300 ?

So this means the ports are running at 1gbit so it is not a simple cable issue.

You could be taking errors on the cable but that it not real likely. Try to ping the router IP both directly connected and via the switch . You should see packet loss if there a bad cable..

If you have a simple coupler try to hook the cable going to pc directly to the cable going to the router. That way you have the exact same cables with the only difference being a coupler vs a switch.

At some point you spend the $20 and get a new switch out of frustration and hope that fixes it.
 

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