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Aspirant

CM1200 slows down after 24-48 hours of uptime when using link aggregation

If I hook up my CM1200 to my router (an Asus RT-AX88U) in Link Aggregation mode, it seems to be consistenly slow down to only around 66-ish% of the full connection speed after somewhere between 24 and 48 hours of uptime.  The only thing which seems to fix this is rebooting the CM1200.  Additionally, I've had it running for at least a week now with Link Aggregation disabled, and I'm not seeing any slowdown, so it would appear that Link Aggregation is related to the problem.

 

The firmware of the CM1200 shows up as V1.01.02, for reference.

Model: CM1200|Nighthawk Multi-Gig Speed Cable Modem
Message 1 of 151
Guru

Re: CM1200 slows down after 24-48 hours of uptime when using link aggregation

What is your ISP speed UP and Down? LAG is used mostly for 1Gb ISP connections.

@vkdelta 

My Setup (Cable 1Gbps/50Mbps)>CM1200(LAG Disabled)>RBK853 v3.2.16.22
RBK50 v2.7.2.102
Additional NG HW: C7800/CM1100/CAX80/CM2000, Orbi CBK40, R7800, R7960P, EX7500/EX7700, XR450 and WNHDE111
Message 2 of 151
Aspirant

Re: CM1200 slows down after 24-48 hours of uptime when using link aggregation

I've got 1Gbps down and ~20-30Mbps up.  I can get largely the same speeds with a single cable, but the slowdown is still kind of concerning on the off chance I can eventually get faster speeds.

Message 3 of 151
NETGEAR Employee

Re: CM1200 slows down after 24-48 hours of uptime when using link aggregation

this is interesting as I have not heard of it..

 

Is this reproducible in your environment?

which ISP are you with?

Does the problem go away if you reboot the router?

How Long does it take the issue to appear?

 

Message 4 of 151
Aspirant

Re: CM1200 slows down after 24-48 hours of uptime when using link aggregation

It's pretty consitently reproducible to me.  I had to turn off link aggregation so I wouldn't have to reboot the modem every other day or so.

 

My ISP is RCN.

 

I'm fairly certain that rebooting the router did not help, only rebooting the modem fixed it.

 

I'm not 100% sure how long it takes to manifest, since it would frequently start happening while I was asleep or at work, but it is definitely greater than 24 hours, and less than 48 hours.

 

Message 5 of 151
NETGEAR Employee

Re: CM1200 slows down after 24-48 hours of uptime when using link aggregation

and you just let the modem run as-is with regular internet use.. Nothing special.. Is that correct?..

 

will check it on our side.

Message 6 of 151
Aspirant

Re: CM1200 slows down after 24-48 hours of uptime when using link aggregation

I may have brought up the Connection Status and Event Log pages once or twice, but that was mostly after it had slown down to see if I could find any obvious problems (I couldn't). Definitely at most I may have looked at the a few of the pages in the modem's browser UI without changing any settings.

Also while I'm thinking about it, I think I checked the Link Aggregation setting while it was slow once, and it reported Link Aggregation as disabled even though it was seemingly active. That may be related.
Message 7 of 151
Guru

Re: CM1200 slows down after 24-48 hours of uptime when using link aggregation

@vkdelta ... have asked @AbhayB in another thread already: 

 

Is there a common aggregation mode "standard" agreed between the makers of cable modems and routers? Asking because when we check Asus that they talk of dynamic 802.3ad/LACP for WAN port aggregation - while Netgear does not show any trace on the aggregation mode implemented - neither on the cable modems, nor on the routers supporting WAN aggregation. More than poor and non-professional documentation, poor KB entries, ...

Message 8 of 151
NETGEAR Employee

Re: CM1200 slows down after 24-48 hours of uptime when using link aggregation

CM1200 runs IEEE 802.3ad/LACP as well.  (I believe this is the most common method on every other router as well)

xmit Hash policy is Layer3+4 (https://www.kernel.org/doc/Documentation/networking/bonding.txt)

 

 

Message 9 of 151
Guru

Re: CM1200 slows down after 24-48 hours of uptime when using link aggregation

@vkdelta the point is that Netgear does _nowhere_ document that the modems and routers WAN aggregation does use 802.3d LACP. Instead, we get some point KB entries e.g. only for the AX12, which would be applicable to many more Nighthawk AX (RAX) and the basic Nighthawk routers, too. Quite a mess. Unfortunately it's not about what we would like to believe - I would have believed the WAC540 does 802.3ad LACP as it was even in the docs, but discovered the hard way that it's static LAG only (docs are supposed to be fixed in the meantime)..

Message 10 of 151
NETGEAR Employee

Re: CM1200 slows down after 24-48 hours of uptime when using link aggregation

as far as I know, it shows in the GUI for CM1200 and also in the user manual.

when the customer enables/disabled LAG, it does show it is 802.ad/LACP.

same with RAX80, it shows in the GUI as well. (I did not check the user manual).

 

 

 

 

 

 

Message 11 of 151
NETGEAR Employee

Re: CM1200 slows down after 24-48 hours of uptime when using link aggregation

UM

Message 12 of 151
NETGEAR Employee

Re: CM1200 slows down after 24-48 hours of uptime when using link aggregation

rax80

Message 13 of 151
Guru

Re: CM1200 slows down after 24-48 hours of uptime when using link aggregation

CM1200 UM has it, indeed. 

Message 14 of 151
Guru

Re: CM1200 slows down after 24-48 hours of uptime when using link aggregation

Look @vkdelta  ... https://www.asus.com/us/support/FAQ/1039053/ how easy could it be?

Message 15 of 151
Guru

Re: CM1200 slows down after 24-48 hours of uptime when using link aggregation

https://kb.netgear.com/000051185/What-are-link-aggregation-and-LACP-and-how-can-I-use-them-in-my-net...

 

https://kb.netgear.com/000060872/How-do-I-set-up-LAN-aggregation-on-my-NETGEAR-Nighthawk-Tri-Band-AX...

My Setup (Cable 1Gbps/50Mbps)>CM1200(LAG Disabled)>RBK853 v3.2.16.22
RBK50 v2.7.2.102
Additional NG HW: C7800/CM1100/CAX80/CM2000, Orbi CBK40, R7800, R7960P, EX7500/EX7700, XR450 and WNHDE111
Message 16 of 151
Guru

Re: CM1200 slows down after 24-48 hours of uptime when using link aggregation

Both KB entries are very generic resp. talk of LAN port aggregation only @FURRYe38 . 

 

Look here - How do I set up Ethernet port aggregation between my NETGEAR Nighthawk Multi-gig Speed Cable Modem a... - this is one of the very misleading and poor KB entries. Multi-Gig is something different (it's used in the industry for GbE ports capable of operating at 2.5Gb and 5 Gb speed!), and there is no word of the aggregation supported/required. Just marketing rubbish - a typical "product" of the Netgear Consumer business unit. In one word: Garbage.

Message 17 of 151
Guru

Re: CM1200 slows down after 24-48 hours of uptime when using link aggregation

I agree and presume the KBs could use some updating. 

My Setup (Cable 1Gbps/50Mbps)>CM1200(LAG Disabled)>RBK853 v3.2.16.22
RBK50 v2.7.2.102
Additional NG HW: C7800/CM1100/CAX80/CM2000, Orbi CBK40, R7800, R7960P, EX7500/EX7700, XR450 and WNHDE111
Message 18 of 151

Re: CM1200 slows down after 24-48 hours of uptime when using link aggregation


@Pokemaniac wrote:

If I hook up my CM1200 to my router (an Asus RT-AX88U) in Link Aggregation mode, it seems to be consistenly slow down to only around 66-ish% of the full connection speed after somewhere between 24 and 48 hours of uptime.  The only thing which seems to fix this is rebooting the CM1200.  Additionally, I've had it running for at least a week now with Link Aggregation disabled, and I'm not seeing any slowdown, so it would appear that Link Aggregation is related to the problem.

 

The firmware of the CM1200 shows up as V1.01.02, for reference.


I have a CM1150v on firmware 2.02.04 (which is the lastest Comcast just pushed it recently in the past week) and when I turn on LAG my connection will slow down within 24 hours, it did the same on the previous firmware 2.02.03. So there is something definitely not right in the firmware that is causing this to happen and this is the first post I have seen on the Netgear forum that talks about this issue. My ISP is Comcast and my speed tier is their gigabyte plan. I have never had it last longer then 24 hours before the speed degrades.Also i might add that my CM1150v is a beta unit that I was sent in the beta test for this device on Comcast.

Message 19 of 151

Re: CM1200 slows down after 24-48 hours of uptime when using link aggregation

I have the same thing happen on this modem as well as my Motorola Mb8600 so it’s definitely a Comcast issue. After 48 hours or so speeds drop to a max of about 650mbps with LACP enabled.
Model: CM1150V|DOCSIS 3.1 Nighthawk® Multi-Gig Speed Cable Modem for XFINITY® Voice
Message 20 of 151

Re: CM1200 slows down after 24-48 hours of uptime when using link aggregation


@YoungSpicket wrote:
I have the same thing happen on this modem as well as my Motorola Mb8600 so it’s definitely a Comcast issue. After 48 hours or so speeds drop to a max of about 650mbps with LACP enabled.

Mine drop lower then that, my download ends up well below 100Mbps typically down to about 20 or 30. First I have seen on any forum about other modems having the same problem.

Message 21 of 151
Guide

Re: CM1200 slows down after 24-48 hours of uptime when using link aggregation

Here is the issue and fix. I have the same moden and the Nighthawk AX8 router. My modem was giving me speeds at the average 900's mb/sec and every 12hrs, the speeds would drop to 12mb/sec. I would the reset the modem and the speeds would increase to my 900's mb/sec speeds. I then tried aggregation and it worked for a couple of days my speeds stayed at 900's mb/sec without issue then it began to drop back to 12mb/sec. With the AX8, you can test speeds directly from the router/modem and then I would test the speeds on my Nvidia Shield and they would match. First, Comcast is pissed that you are using their modem for $13/month. Secondly, you will actually have to contact a technical support supervisor. So I decided to call XFINITY (Comcast) and raise hell. They first began to speak me me as I am an idiot and dont know anything. You will have to reiterate that the Nighthawk CM1200 is compatible to their network and is also listed on their website. They ask you speedtest questions and things. Then they will talk down to you. Log into your modem and tell them you can see the frequency and they are not what they should be. Now asked them to bump up your speeds and then lock in the modem. They will argue a bit but they have to do it. Once modem is locked in I. And speeds are bumped, you will not have to restart the modem every 12-24hrs. They are trying to force you to use their modem which then dictates the speeds your devices are allowed to get.

P.S. I have a Galaxy S10 5g, and need to know how to configure the wifi settings to get almost gigabit speeds on 5Ghz. I can only get 325-450mb/sec, which I know the phone is capable of faster speeds
Model: CM1200|Nighthawk Multi-Gig Speed Cable Modem
Message 22 of 151
Star

Re: CM1200 slows down after 24-48 hours of uptime when using link aggregation

So I'm having the exact same issue -- with 802.3ad link aggregation (LACP/LAG) enabled, after about 24 hours my speeds drop from gigabit to 20-30Mbit/s.  I am on firmware version 1.02.02 and hardware version 1.01.  Rebooting solves the issue until it comes back.  It's a real bummer and the only reason I bought this modem.  I've only had it for a week or so.

Model: CM1200|Nighthawk Multi-Gig Speed Cable Modem
Message 23 of 151
Guide

Re: CM1200 slows down after 24-48 hours of uptime when using link aggregation

Did you read my post????? It is not the modem, it is Comcast. Read my post and do AS I did and it will fix your issues
Message 24 of 151
Star

Re: CM1200 slows down after 24-48 hours of uptime when using link aggregation

Hey there, I did read your post, but I'm not sure that I really understand what you're on about.  My cable modem frequencies are unchanged from when the issue is occurring versus when they are not.  Furthermore, the signal to noise ratios (SNR) look amazing (around 42dB) and I'm showing no uncorrectable errors on any channel and little no correctable errors as well, shockingly.  What were your statistics like prior to calling Comcast?  I'm curious what statistic or metric I can point them to to indicate that there is a specific problem, since I'd love for it to be as easy as calling technical support and getting them to do something.  With no indication that the issue is indeed on their side, it's hard to justify "raising hell", as much as we all like yelling at Comcast.

 

A metric that I do find interesting is that I see increased latency, upwards of 300ms RTT, to the cable modem's management IP itself (192.168.100.1) when this issue is occurring.  This leads me to believe it's a runaway process of some kind on the device rather than an upstream issue.

Message 25 of 151
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