NETGEAR is aware of a growing number of phone and online scams. To learn how to stay safe click here.
Forum Discussion
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 didn't do a search and made a similar post here Duplicate Post.
I am having the same problem on Spectrum; I have the 1Gbps service and initially connected to my pfSense router via LACP. My findings where similar in that if I reset the connection my speeds would return to normal. However my time frame for the reduced throughput was significantly lower than reported by others.
Initial speeds would be 800Mbps - 1Gbps but after four to five hours the speeds would drop to ~20Mbps with high latency. I found that resetting the LACP link would return speeds to normal. This lead to me to wondering if it was a firmware issue, maybe the hashing used on the CM1200? So I put a switch between the CM1200 and my pfSense router. This would extend the time frame between slow downs but inevitably they would return.
At this point I am have removed the LACP and I am down to one port. While my speeds are horrendous they are much better than 20Mbps; I attribute this Spectrum over provisioning or some other shenanigans.
I am attach screen shots of speed tests and a pdf that shows my signal levels.
I would like to think that Spectrum is not playing any silly games with my connection but I have no proof that they are not; my main goal is to try and figure out what is going on with this. If anyone has any recommended troubleshooting steps please let me know. I have a good amount of networking knowledge and want to get this fixed.
vkdelta- Any information on possible fixes? If I have to call Spectrum and give them hell I can but don't want to take that step until I know it is them that is the problem.
The issue is not with Spectrum. I'm on Spectrum and have been using LAGG with my MB8600 with no issues. I can hit 1.22Gbps with my pfsense build. I have also tried a SB8200 without this issue. The Netgear CM1200 LACP is broken and must be out of ieee standard because if you take one of the members down the interface will no longer pass traffic. That is one of the most basic fuctions of 802.3ad "redundancy of link if a members connection is lost"
I dont think its hash related because I tested that as well using my Cisco 3850 switch. Same results with the CM1200 but I would interrested in hearing from someone with the a multigig Netgear router with the CM1200 but I wouldn't be surprised if the results are the same.
If you want multigig with Spectrum or any other provider look at the MB8600 or SB8200 and I guess maybe the CM1100 but I have not tested that model.
I can confirm that your ISP is not the issue. After several days of bouncing around with NETGEAR support (I kept getting bounced between the switch and cable modem teams since both devices are NETGEAR) and hitting up NETGEAR on Twitter, it was clear that they don't consider this a high priority issue. Even IF they do eventually fix this problem, it may take months to roll out a firmware update since your ISP has to push that to your cable modem. Long story short, if you're going to do LACP don't even bother with the CM1200. The fact that a NETGEAR employee hasn't even replied to this thread in a long time confirms to me that they just don't care. I've had great luck with the Motorola MB8600 and I've heard good things about the SB8200 as well. I'm getting around 1.2Gbps with my MB8600 and it's been up so far for almost 10 days. See attached screenshot for evidence.
The thing that gets me is that I assume the CM1200 is just running Linux; the Linux bonding driver has supported 802.3ad link aggregation / LACP for a very long time and is very, very mature. I'm not sure what NETGEAR has done with this firmware to introduce this issue.
- Kenny
kvanals wrote:I can confirm that your ISP is not the issue. After several days of bouncing around with NETGEAR support (I kept getting bounced between the switch and cable modem teams since both devices are NETGEAR) and hitting up NETGEAR on Twitter, it was clear that they don't consider this a high priority issue. Even IF they do eventually fix this problem, it may take months to roll out a firmware update since your ISP has to push that to your cable modem. Long story short, if you're going to do LACP don't even bother with the CM1200. The fact that a NETGEAR employee hasn't even replied to this thread in a long time confirms to me that they just don't care. I've had great luck with the Motorola MB8600 and I've heard good things about the SB8200 as well. I'm getting around 1.2Gbps with my MB8600 and it's been up so far for almost 10 days. See attached screenshot for evidence.
The thing that gets me is that I assume the CM1200 is just running Linux; the Linux bonding driver has supported 802.3ad link aggregation / LACP for a very long time and is very, very mature. I'm not sure what NETGEAR has done with this firmware to introduce this issue.
- Kenny
Good to know!
I'm not writing off the CM1200 just yet; if nothing else I would like to help figure out what the problem is.
It is probably running a paired down version of the linux kernel but just because the driver is mature in x86/x64 does not mean that it is simple plug and play with their hardware. I am sure there is a significant amount of optimization that is required to get it to run on their hardware. I would venture a guess that their CM is using an ARM processor or it is running a RTOS (Real-Time OS) that while it does use a lot of the code they can't just dump the entire linux kernel and drivers on the CM.
Well, after two support tickets (since both my switch and modem are/were under warranty and had online and email support still) and getting bounced around, I lost faith in trying to solve the issue with NETGEAR. And honestly, that's your only hope since you can't fetch the firmware binary blobs yourself and even if you could AND had the means to unpack them, there's no way to load the image onto the device yourself if you or someone else was able to figure out what the issue is. As far as the OS on the device, it is certainly only conjecture at this point, but if it indeed is Linux I'm not sure what permutation of hardware configuration would lead them to develop their own LACP driver, even on a non-x86/x86_64 architecture like ARM/AARCH64/MIPS/etc.
To be honest, the only reason I'm still replying to this thread is that I'm salty that nobody at NETGEAR has even acknowledged that this is clearly an issue with an advertised feature and I'm hoping that keeping the thread alive will get it noticed. (Which would definitely help you if you're staying on the CM1200 bandwagon.)
- Kenny
