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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 an...
I really like this modem but with my ISP being Suddenlink I am not sure they will ever have an update for this modem. I will go get the Moto 8600 as it will do the aggrigation without issues.
I wish that you could update the firmware as we buy these our self.
Since I originally posted about my CM1200 link aggregation performance degradation I have found that performance can be restored without a power cycle or modem reset. Performance can be restored by a link disable / enable. This can be done by disconnecting and reconnecting one of the Ethernet cables or by disabling and enabling one of the switch ports that the CM1200 is connected to. When I take either of these actions full performance is immediately available. Then after another two to four hour time period performance will again be severely degraded. Repeating the change of port state will again restore performance. The change of port state to restore performance can be done on either of the connected ports.
From my testing a down/up of one of the connected ports has restored performance multiple times, but each time performance degrades after two to four hours. The only result of my testing that I did not expect was that when in degraded mode if I disabled one port and left it disabled, performance was restored to what one would expect in a non port aggregation mode. However, again after two to four hours performance degraded. I then had to down/up the port that was active to restore performance.
In terms of degradation my download speeds drop from 1150 Megabits to 20 to 25 Megabits. My upload speeds drop from 40 Megabits to 20 to 25 Megabits.
I have an open case with Netgear support on this problem.
Thanks for the quicker fix! Can confirm that this works, so you don't need to always reboot. I wish Netgear would acknowledge this or push out a firmware update. I'm considering returning this modem before my return window is up and buying one of the many other modems mentioned in this thread that work with WAN Aggregation and do not have slowdowns after 2-4 to 24-48 hours.
After finding an undocumented telnet interface on the switch my CM1200 is connected to I now have a script to telnet to the switch disable and enable ports and restore performance. I have run this script multiple times over almost a week with performance being restored each time.
- telnet to switch
- disable the first port of the CM1200 connection, delay 5 seconds, enable the port
- delay 5 seconds
- disable the second port of the CM1200 connection, delay 5 seconds, enable the port
- quit
I believe this script can be refined to reduce the delays and only disable one port, but I have not had time to refine further so I took the conservative approach and it works in my environment. If this continues to work, I plan to automate this process to run periodically until there is a fix for this problem or until a modem with a 2.5 Gb or above interface is available.
So I have not been commenting on this in a while because I figured that I would just watch how many people complaing about the CM1200. The last time I was on, some mentioned that I need to post a pic of the uptime, so I decided to..... I will also post a pic of the speedtest from the NIGHTHAWK AX8
In case people are still looking for hard proof, I've taken the liberty of recording a video of my own experience in ownership of a CM1200. I'm using Comcast Xfinity in Portland, Oregon, my CM1200 is running firmware V1.02.02, and it's connected via 802.3ad (LACP) link aggregation to a Netgear SG-4860 running 2.4.4-RELEASE-p3. My current speed tier is 175/5, but I was paying for Gigabit internet shortly after moving into this apartment and was seeing the same symptoms everyone here's been reporting: after about 24 hours of uptime, bandwidth is throttled to around 20Mbps up/down. Prior to this weekend, I thought that reboots were the best way to get service back, but resetting one of the ports in the LAGG group on my pfSense appliance also works -- I'd like to thank everyone who suggested this.
As you can see in this video, my modem's been online for around 5 days, and though it isn't shown, my pfSense appliance has been online for about 9 days. After bouncing one of the interfaces in the LAGG group, Comcast's own speed test (which you should assume is exaggerating the speed of my connection) reports that my speed increases ten-fold. The last interface reset I'd made to a port in the LAGG group was a little under an hour prior, so to put this another way: it takes less than one hour for speed to degrade by 90%. I believe the bandwidth degradation is caused by utilization, but whether that's raw packet throughput or connections being made, I couldn't tell you without more information, and modems are unfortunately locked down.
I turned off
anthonypants wrote:In case people are still looking for hard proof, I've taken the liberty of recording a video of my own experience in ownership of a CM1200. I'm using Comcast Xfinity in Portland, Oregon, my CM1200 is running firmware V1.02.02, and it's connected via 802.3ad (LACP) link aggregation to a Netgate SG-4860 running 2.4.4-RELEASE-p3. My current speed tier is 175/5, but I was paying for Gigabit internet shortly after moving into this apartment and was seeing the same symptoms everyone here's been reporting: after about 24 hours of uptime, bandwidth is throttled to around 20Mbps up/down. Prior to this weekend, I thought that reboots were the best way to get service back, but resetting one of the ports in the LAGG group on my pfSense appliance also works -- I'd like to thank everyone who suggested this.
As you can see in this video, my modem's been online for around 5 days, and though it isn't shown, my pfSense appliance has been online for about 9 days. After bouncing one of the interfaces in the LAGG group, Comcast's own speed test (which you should assume is exaggerating the speed of my connection) reports that my speed increases ten-fold. The last interface reset I'd made to a port in the LAGG group was a little under an hour prior, so to put this another way: it takes less than one hour for speed to degrade by 90%. I believe the bandwidth degradation is caused by utilization, but whether that's raw packet throughput or connections being made, I couldn't tell you without more information, and modems are unfortunately locked down.
After having made this post last year, I spent some time troubleshooting and working on scripting a method of cycling the LACP member ports on my Netgate appliance, but in the end I gave up and turned off link aggregation on the modem. However, this morning, I've just received firmware version V2.02.05 (which isn't even listed on Netgear's own documentation), and because there's zero chance of finding out from Comcast or Netgear if this firmware resolves the LACP issue, I'll have to perform some testing and report back.
Let us know your results.
