comcast gigabit - getting slower speeds now ??

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dustinarden
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Joined: 21 Feb 2015
Posts: 52

PostPosted: Wed Jun 12, 2019 21:00    Post subject: comcast gigabit - getting slower speeds now ?? Reply with quote
Ok. I've been on the 150mb plan for a while. great speeds. Just this morning I tested and got 150ish down.

I upgraded my service and got my new arris docsis 3.1 modem in today. Once they provisioned the modem i was only getting like 25 down and 25 up.

Tested with laptop directly to the modem and got gigabit. Now when i test from my office where I was getting 150 before .. i'm only getting like 7 or 15 at best. it doesnt make any sense at all.

I've overclocked to 1200 and enabled SFE but its seemingly doing nothing. I did a test from my phone via the AC network and it is getting like 50ish ... something isnt right here and I'm honestly out of ideas.

Current router is the R7000P on DD-WRT v3.0-r39345M kongac (04/03/19)

help?!
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kernel-panic69
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Joined: 08 May 2018
Posts: 14125
Location: Texas, USA

PostPosted: Wed Jun 12, 2019 21:39    Post subject: Reply with quote
There has been many commits since that build. May want to try the latest <Kong> build and see if anything changes:

https://forum.dd-wrt.com/phpBB2/viewtopic.php?t=320063
dustinarden
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Joined: 21 Feb 2015
Posts: 52

PostPosted: Wed Jun 12, 2019 21:49    Post subject: Reply with quote
Thanks for the reply!

Just upgraded to the newest version available.

Same problem unfortunately.
flyzipper
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Joined: 21 Feb 2016
Posts: 504

PostPosted: Wed Jun 12, 2019 21:55    Post subject: Reply with quote
Is your new modem routing, or in bridged mode? Is your R7000P routing or a wireless access point? You'll want a combo which isn't double-routing and double-NATing.

Also, check/swap the Ethernet cable that's connecting the 7000P to the modem.

Lastly, the built-in SpeedChecker service on your DD-WRT can report separate internet and wifi speed results so that might narrow things down a bit.

http://<your router IP>/Speedchecker.asp
dustinarden
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Joined: 21 Feb 2015
Posts: 52

PostPosted: Wed Jun 12, 2019 22:27    Post subject: Reply with quote
It's not the cable or anything simple like that unfortunately. Literally the only thing in my entire setup that has changed is the modem and the specific tier of Comcast service. I really feel like it's something to do with the interaction between my modem and the router based on Comcast settings or something. Literally my speed has been reduced by some huge amount just cause of the modem ...
flyzipper
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Joined: 21 Feb 2016
Posts: 504

PostPosted: Wed Jun 12, 2019 23:34    Post subject: Reply with quote
Understood, that's why I suggested checking the things I did.
dustinarden
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Joined: 21 Feb 2015
Posts: 52

PostPosted: Thu Jun 13, 2019 1:41    Post subject: Reply with quote
to better answer your question my router is setup as both a wifi access point and is my core router.

I'm trying to access the modems webGUI but so far cant. Its essentially default out of the box configuration.
dustinarden
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Joined: 21 Feb 2015
Posts: 52

PostPosted: Thu Jun 13, 2019 2:15    Post subject: Reply with quote
I tried doing the speed checker link that you posted, but nothing happens unfortunately.
flyzipper
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Joined: 21 Feb 2016
Posts: 504

PostPosted: Thu Jun 13, 2019 3:11    Post subject: Reply with quote
RE: I tried doing the speed checker link that you posted, but nothing happens unfortunately.

Access it via the DD-WRT GUI > Services > SpeedChecker tab.

Enable it, run the tests and disable it.

RE: I'm trying to access the modems webGUI but so far cant. AND tested with laptop directly to the modem and got gigabit

If your laptop is assigned a non-routable address when it's connected directly to the modem, the modem is routing and performing NAT (not something you'd want if your R7000P is "setup as both a wifi access point and is my core router"). On the other hand, if your laptop is assigned a routable address, then the modem is likely in bridge mode. The modem being in bridge mode is what you'd want with an external router, but knowing this info should also help you figure out what's needed to connect to the modem's GUI (likely different depending on whether it's behaving like a router or a bridge).

RE: Tested with laptop directly to the modem and got gigabit. Now when i test from my office where I was getting 150 before .. i'm only getting like 7 or 15 at best

Expand on "from my office" a bit because that's not clear to anyone but you.

New Modem < Ethernet < laptop = 1Gbps
New Modem < Ethernet < R7000P < wifi < office client = 7-15Mbps
Old Modem < Ethernet < R7000P < wifi < office client = 150Mbps

What speeds do you get from this setup?

New Modem < Ethernet < R7000P < Ethernet < laptop = ?
New Modem < Ethernet < R7000P < wifi < laptop = ?

Is your R7000P connected to the correct port on your new modem?

If you force the WAN port on the R7000P to negotiate at 100Mbps (Setup/VLANs tab), what's your performance like? If it improves from 7-15Mbps to around 80Mbps, that points at the cable between your new modem and the R7000P. If those devices auto negotiate a GB link speed, and the cable isn't up to the task, you'll get horrible performance with all the packet renegotiation.
dustinarden
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Joined: 21 Feb 2015
Posts: 52

PostPosted: Thu Jun 13, 2019 3:20    Post subject: Reply with quote
@flyzipper - first off ... thank you. the completeness of your reply is refreshing and I do truly appreciate it.

I'm going to go through your list of recommendations in the morning (i've had some drinks and its getting late) and i'll report back on each suggestion for sure.

As an aside. The whole comcast thing has been nagging me .. so I cloned the mac address of my gaming rig using the mac addy clone menu in ddwrt. restarted the modem and router and guess what .. my speeds instantly went to 80 +mbps instead of 5. upload was still crap but whatever.

what does that mean? I swear I feel like the new modem, comcast, and my router simply are not playing nice with each other.
kernel-panic69
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Joined: 08 May 2018
Posts: 14125
Location: Texas, USA

PostPosted: Thu Jun 13, 2019 3:32    Post subject: Reply with quote
If they setup your new modem / service with a specific device, that is what it is looking for to be directly connected, I believe. I always had to swap NICs or do the initial setup the fun way with Cox and Comcast because of this, due to my x86 Slackware router / proxy / firewall / gateway rig in the past. Some providers are finicky that way.
dustinarden
DD-WRT User


Joined: 21 Feb 2015
Posts: 52

PostPosted: Thu Jun 13, 2019 3:47    Post subject: Reply with quote
i'm getting 5 down again and now .. 5 up. realized i already talked about mac cloning in my old post, lol.

WTH is going on with my speeds. Its crap like this that makes me assume its something with how comcast provisioned my modem or something. Should i hard reset it and try again?

flyzipper wrote:
RE: I tried doing the speed checker link that you posted, but nothing happens unfortunately.

Access it via the DD-WRT GUI > Services > SpeedChecker tab.

Enable it, run the tests and disable it.


Ok will do. I'll do this tomorrow morning and report back.


flyzipper wrote:

RE: I'm trying to access the modems webGUI but so far cant. AND tested with laptop directly to the modem and got gigabit

If your laptop is assigned a non-routable address when it's connected directly to the modem, the modem is routing and performing NAT (not something you'd want if your R7000P is "setup as both a wifi access point and is my core router"). On the other hand, if your laptop is assigned a routable address, then the modem is likely in bridge mode. The modem being in bridge mode is what you'd want with an external router, but knowing this info should also help you figure out what's needed to connect to the modem's GUI (likely different depending on whether it's behaving like a router or a bridge).


I had to refresh DHCP when doing this. Confirmed via ifconfig that I had a publically routeable IP address and thats when I did the speedtest that netted gigabit speed. I had to reboot the laptop and modem if i remember correctly before the laptop would pull a publically routable ip address allowing me to conduct the test.

flyzipper wrote:

RE: Tested with laptop directly to the modem and got gigabit. Now when i test from my office where I was getting 150 before .. i'm only getting like 7 or 15 at best

Expand on "from my office" a bit because that's not clear to anyone but you.


So we just moved into this house and I had a professinal come in an rewire the house. Line from the street goes STRAIGHT to the cable modem in a centralized utility room in our house. That modem feeds the R700P which in turn feeds an 8 port PoE switch. That switch feeds the various rooms that have ethernet. My office being one of them. There are 2 synology NAS's and two rPi's attached directly to the R7000P.

flyzipper wrote:

New Modem < Ethernet < laptop = 1Gbps
New Modem < Ethernet < R7000P < Ethernet < 8port switch < Ethernet < cheap netgear 100/1000 hub < Ethernet < office client = 7-15Mbps
Old Modem < Ethernet < R7000P < Ethernet < 8port switch < Ethernet < cheap netgear 100/1000 hub < Ethernet < office client= 150Mbps

Fixed.

flyzipper wrote:

What speeds do you get from this setup?

New Modem < Ethernet < R7000P < Ethernet < laptop = ?
New Modem < Ethernet < R7000P < wifi < laptop = ?

No clue. I'll test that tomorrow and update the post.

flyzipper wrote:

Is your R7000P connected to the correct port on your new modem?

Funny you mention that. This modem has two ports where as the old one only had one. I've had it in port "1" all day including when i got the gigabit speed on the laptop. When I did the mac address clone in DDWRT and power cylced the modem I also changed to port "2".

flyzipper wrote:

If you force the WAN port on the R7000P to negotiate at 100Mbps (Setup/VLANs tab), what's your performance like? If it improves from 7-15Mbps to around 80Mbps, that points at the cable between your new modem and the R7000P. If those devices auto negotiate a GB link speed, and the cable isn't up to the task, you'll get horrible performance with all the packet renegotiation.


I'll try this tomorrow.
dustinarden
DD-WRT User


Joined: 21 Feb 2015
Posts: 52

PostPosted: Thu Jun 13, 2019 13:42    Post subject: Reply with quote
flyzipper wrote:
RE: I tried doing the speed checker link that you posted, but nothing happens unfortunately.

Access it via the DD-WRT GUI > Services > SpeedChecker tab.

Enable it, run the tests and disable it.



It doesnt appear that I have this in my GUI. There isnt a "speedchecker" tab.
dustinarden
DD-WRT User


Joined: 21 Feb 2015
Posts: 52

PostPosted: Thu Jun 13, 2019 14:05    Post subject: Reply with quote
Got access to my surfboard modem sorted. There isnt really anything in there that I can "change" to alter settings. Did copy / paste some of the messages and statistics out though. I'll post those in a bit if they are needed.

Importantly I undid the MAC addy clone on the R7000P, rebooted the modem and ran another speed test. again .. i was able to hit 80mbps down and like 30 something up on the first try. When you try again ... speeds tank again.
kernel-panic69
DD-WRT Guru


Joined: 08 May 2018
Posts: 14125
Location: Texas, USA

PostPosted: Thu Jun 13, 2019 14:21    Post subject: Reply with quote
dustinarden wrote:
flyzipper wrote:
RE: I tried doing the speed checker link that you posted, but nothing happens unfortunately.

Access it via the DD-WRT GUI > Services > SpeedChecker tab.

Enable it, run the tests and disable it.



It doesnt appear that I have this in my GUI. There isnt a "speedchecker" tab.


"Inconsistencies in DD-WRT". The R7000P is not an R7000, and the builds are probably different. Then again, it may have been added since the build you are running...
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