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Elohim
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Losing Speed between DSL modem and router...

Thu Feb 07, 2019 12:08 pm

Hey Guys,

Greetings from snowy NW rural Wisconsin, where the snow is white, the cows are plentiful, and where we feel lucky to get our whopping 8Mbps DSL Internet and are totally envious (even the cows are envious) of the rest of you modernly connected folk! :)

I have an strange issue that I can't quite figure out and was hoping for help on.

I was recently running a 10 year old Actiontec GT724WGR DSL modem. Unfortunately it bit the dust and wouldn't sync up anymore earlier this week. As it turns out Best Buy and Office Depot no longer carry this equipment since the phone companies pretty much monopolize the market. I did what any self respecting computer lover would do and took a 90 minute trip over to Minneapolis to visit the closest Micro Center to my place and pickup a new one and some other odd knickknacks I thought looked interesting as I wandered the store like a kid in a store with only candy aisles.

Anyway, I got my new Actiontec GT784WN-01 DSL modem home, hooked it up, got my PPPoE info put in and it synced up and I was off. I noticed with my first speed test that, strangely, my Internet speed was 5-6 Mbps instead of my normal 7-8Mbps... At the time I was connected through an ASUS RT-AC66U router. So then I re-connected through the actiontec wifi and re-ran the speed test and I got my full 8Mbps.

So... for some reason not all of my copious 8Mbps bandwidth is transferring across the ethernet cable from my modem to the WAN port on my router. And I haven't a clue why that would be, since this problem did not exist with my old DSL modem. I plugged that same cable into a laptop, directly connecting to the DSL modem ,and got all my bandwidth again. So teh cable is fine... So somehow my ASUS router is not "accepting" all the bandwidth?

So, yeah.... any ideas guys?

Thanks in advance!
 
The Egg
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Re: Losing Speed between DSL modem and router...

Thu Feb 07, 2019 12:50 pm

I assume you've changed the CAT6 cable and updated the router to the latest firmware?
 
Captain Ned
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Re: Losing Speed between DSL modem and router...

Thu Feb 07, 2019 1:17 pm

It sure shouldn't be the Asus router as I routinely saw all 30 mbps I was paying for back when I had an RT-66U
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ludi
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Re: Losing Speed between DSL modem and router...

Thu Feb 07, 2019 1:29 pm

This might seem obvious, but was anything else using the bandwidth when you ran the speed test? If your Internet was offline for a few days then something may have been downloading a backlog of updates. When you connected directly to the modem, you would have obviously disconnected those other devices.
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Elohim
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Re: Losing Speed between DSL modem and router...

Thu Feb 07, 2019 1:30 pm

The Egg wrote:
I assume you've changed the CAT6 cable and updated the router to the latest firmware?


The DSL modem firmware is up to date as is the router. The cable was verified as good when I direct connected the laptop to the DSL and got full speed. Good ideas, but not the culprits unfortunately.
 
Elohim
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Re: Losing Speed between DSL modem and router...

Thu Feb 07, 2019 1:40 pm

ludi wrote:
This might seem obvious, but was anything else using the bandwidth when you ran the speed test? If your Internet was offline for a few days then something may have been downloading a backlog of updates. When you connected directly to the modem, you would have obviously disconnected those other devices.


Unfortunately this is not it either. I can switch my wireless from the router to the modem and the speed is always 2Mbps higher on the modem then on the router. It's almost as though QoS is turned on in the modem and is limiting the router to 80% of the bandwidth, but I checked and QoS is off in the modem.

If we only had things in the house, we could just use the modem, but I use the routers to extend my network to another out building I have and also have all my printers in that outbuilding. I do have another identical Asus router out in that other building in Bridge mode, maybe I'll bring that one in, put it back into normal DHCP mode, connect it and see if it experiences the same issue. It's always possible that whatever took my modem caused some damage to my router? 20% slower seems like a strange degradation though if there was some electrical surge. I'll let you know if I see a difference.
 
ludi
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Re: Losing Speed between DSL modem and router...

Thu Feb 07, 2019 2:17 pm

Just to be clear, in the "normal" configuration that is only getting around 6mpbs, you are bridging the modem to the router using PPPoE and letting the router negotiate the DSL connection, correct?

Also worth checking to see if the router has e.g. a Jumbo Frames option enabled. Those sometimes cause issues.
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The Egg
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Re: Losing Speed between DSL modem and router...

Thu Feb 07, 2019 2:22 pm

Yeah, probably an oddball setting. I would reset the router to defaults and see if that resolves it.
 
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Re: Losing Speed between DSL modem and router...

Thu Feb 07, 2019 4:06 pm

Plug a hardline cable into the switch ports on the RT-AC66U and see what you get. You don't note exactly how the AC66 is configured, AP vs Router, but if you get full speed from a connection to the AC66 switch ports, then your problem is something with the wireless. If you get a speed drop, then something about the AC66 is wrong. Did you have the wireless enabled on your preview Actiontec modem? If not, then perhaps its interfering with the AC66?

--SS
 
Elohim
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Re: Losing Speed between DSL modem and router...

Thu Feb 07, 2019 6:24 pm

ludi wrote:
Just to be clear, in the "normal" configuration that is only getting around 6mpbs, you are bridging the modem to the router using PPPoE and letting the router negotiate the DSL connection, correct?

Also worth checking to see if the router has e.g. a Jumbo Frames option enabled. Those sometimes cause issues.


Couldn't find the jumbo frames option, interesting idea. Sorry, the normal configuration is the DSL modem negotiates the PPPoE and the router gets the Internet via its WAN port from the modem. I actually got this figured out now! See my reply to another post. Thanks for the ideas!
 
Elohim
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Re: Losing Speed between DSL modem and router...

Thu Feb 07, 2019 6:25 pm

The Egg wrote:
Yeah, probably an oddball setting. I would reset the router to defaults and see if that resolves it.


Yep, a router reset to defaults did the trick! The only downside is that I would have liked to know what setting was limiting the bandwidth like that. Would have been interesting. Thanks for the suggestion!
 
Elohim
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Re: Losing Speed between DSL modem and router...

Thu Feb 07, 2019 6:26 pm

SecretSquirrel wrote:
Plug a hardline cable into the switch ports on the RT-AC66U and see what you get. You don't note exactly how the AC66 is configured, AP vs Router, but if you get full speed from a connection to the AC66 switch ports, then your problem is something with the wireless. If you get a speed drop, then something about the AC66 is wrong. Did you have the wireless enabled on your preview Actiontec modem? If not, then perhaps its interfering with the AC66?

--SS


The hard line connection gave the same slower speeds, so not a wireless thing. As I mentioned one post earlier, I did get this fixed by resetting the AC66 to factory default. Just wish I knew what the setting was that caused the bandwidth issue. Thank you for the replies!
 
Elohim
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Re: Losing Speed between DSL modem and router...

Thu Feb 07, 2019 6:27 pm

Thanks for all the suggestions folks! The router reset to factory default did the trick!
 
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Re: Losing Speed between DSL modem and router...

Thu Feb 07, 2019 6:31 pm

It might not have even been a specific setting. The router may have just gotten itself into a bad state, which was cleared by the factory reset.

But yeah, the most plausible explanation is that there was some setting which was making the router work harder.
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notfred
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Re: Losing Speed between DSL modem and router...

Fri Feb 08, 2019 12:45 pm

Glad to hear the router reset fixed it.

Just a heads up that it sounds as if you are running double-NAT with the modem configured as a router with PPPoE credentials and then the ASUS configured as another router doing DHCP off the modem. It would be better to configure the modem as a bridge and put your PPPoE credentials in the ASUS router.

Alternatively you could leave the modem running as the router and configure the ASUS as a pure switch and WiFi AP. However the router is generally better at routing than the garbage built in to the modem.
 
Elohim
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Re: Losing Speed between DSL modem and router...

Fri Feb 08, 2019 12:51 pm

notfred wrote:
Glad to hear the router reset fixed it.

Just a heads up that it sounds as if you are running double-NAT with the modem configured as a router with PPPoE credentials and then the ASUS configured as another router doing DHCP off the modem. It would be better to configure the modem as a bridge and put your PPPoE credentials in the ASUS router.

Alternatively you could leave the modem running as the router and configure the ASUS as a pure switch and WiFi AP. However the router is generally better at routing than the garbage built in to the modem.


I am intrigued. Can you expand on the meaning of "better" in your sentence "It would be better to configure the modem as a bridge and put your PPPoE credentials in the ASUS router." Do you just cleaner from a professional point of view (like a comment in your computer code) or actually slightly better in some tangible way?
 
ludi
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Re: Losing Speed between DSL modem and router...

Fri Feb 08, 2019 1:00 pm

Elohim wrote:
I am intrigued. Can you expand on the meaning of "better" in your sentence "It would be better to configure the modem as a bridge and put your PPPoE credentials in the ASUS router." Do you just cleaner from a professional point of view (like a comment in your computer code) or actually slightly better in some tangible way?

The hardware in a decent-quality standalone router is usually better than the hardware in an All-In-One DSL combination modem/router. If you configure the modem as a PPPoE bridge then it will do nothing but convert the raw DSL packets to an equivalent Ethernet format and send them to the router. The router will then perform the protocol conversion and manage the login credentials.

Ideally, this gets you a slightly more stable connection with lower latency since the router can probably manage the DSL packet conversion more efficiently than the modem, especially when the connection is saturated by a large download. Also, the modem will run cooler since most of its hardware will be idle. In my past experience before switching to cable, those AIO DSL modems like to run hot and die young, so unloading it is a big plus.
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notfred
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Re: Losing Speed between DSL modem and router...

Fri Feb 08, 2019 2:04 pm

On top of what ludi mentions, the modem/router often has a pretty buggy router implementation. It used to be common that running BitTorrent would crash them and need a power cycle to recover. It could be anything - memory leaks that mean you need to reboot every week or two.

The double NAT can also cause problems with some gaming, VoIP and Video Conferencing setups.
 
Elohim
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Re: Losing Speed between DSL modem and router...

Fri Feb 08, 2019 4:21 pm

Ludi and notfred convinced me. I am now doing my PPPoE in the router and modem is happily acting as a packet bridge. Thanks for the input!

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