LACP Issues - 1G Cable

[sbstrd]

I am running into an issue with LACP from my cable modem to my router. I have the Arris SB8200. After about 24 hours the connection slows to a crawl (5mbps with higher latencey). An disable/enable of the interface (or physical unplug, plug back in of the ethernet cable) fixes it. To troubleshoot, I disconnected the second ethernet cable, though LACP is still enabled on both sides.

I thought it was a router issue. But then I read a review on a large retail website for the Netgear CM1200, and it sounded strangely familiar:

"So i run this cable modem with LACP enabled (two 1Gig connections from the modem to my routers WAN ports to give me more bandwidth) to my new Netgear RAX80 WIFI 6 router. I thought I was having issues with the router as my download speeds would slow from 1024mbps to 12-20mbps over a 24hr period. After a reboot the speeds would be normal. I returned the RAX80 but the issues persisted. It turns out this is an identified problem with the firmware version Xfinity has deployed to the CM1150V cable modems (you are dependent on your ISP for FW updates to the modem) V2.02.04 is the newest version Xfinity/Comcast deploys and it has a bug relating to LACP.

**UPDATE 1/14/2020**
I disabled LACP and with the single connection to my router the speeds stopped slowing to a crawl. While I wish I could use the features I paid for, Netgear has updated their firmware, but Comcast/Xfinity hasn't approved it yet, but I cant blame Netgear for that."

Has anyone gotten LACP to be stable on either an SB8200 or CM1200???

Signals are all excellent on the Cable Modem.

I am not looking for "why bother" or "you don't need LACP" answers. Yes, I know you only need 1G ethernet cable for 1G internet. That is not the point. The point here is Comcast pushed down the firmware to enable LACP, but there appears to be an issue. I have gotten nowhere with Xfinity Support chat. Even had the technician claim they were a Level 2 escallation engineer and lie to me saying that Comcast does not push down firmware or config files to customer owned cable modems! And then they wouldn't escallate my call when I asked. 😠

[devopsterus]

Wow very neat.  Just this past weekend, I worked on replacing my Netgear router with a custom-built Linux router.  I have the SB8200.  I set up the bonding on Linux with "bond-mode 802.3ad".  Everything works very well, except it slows to a crawl after 12-24 hours.  This setup uses dnsmasq and wide-dhcpv6-client.  

I can simply log into the server and restart the external (bond0) interface, and it recovers.  For those who are wondering, I get about 1.2 Gbps with this configuration, sometimes a bit more.

I can set a cron job to restart the network every so often.  The internal side is 10G fiber, so the idea is only to bounce the external side.

The network bounces in a heartbeat so this is a workable solution, but I'd like to have a better fix long term.

Is it possible to self flash the firmware?

[devopsterus]

Seems like Comcast must do the flashing:

https://arris.secure.force.com/consumers/articles/General_FAQs/Upgrading-Firmware-on-Cable-Devices

"The Cable Operators (MSOs) have complete control of what cable modem/gateway hardware they will allow installed and the firmware it uses, on their cable plant.  This means anything directly connected to the cable plant (COAX) in your house.  They do this to ensure that nothing happens to anyone upstream from your connections.  Cable Operators follow the DOCSIS Specifications that control this methodology of firmware upgrades as well as providing security for the firmware upgrades.  

Cable Operators also run both the products and firmware through their own test cycles to approve any manufacturers’ modems, wireless gateways, and the associated firmware updates for deployment.  This is not an ARRIS only implementation, but the required implementation of any cable device manufacturer.  After an MSO has tested and approved a new version of firmware for a cable device, they will then “push” that new firmware out to the devices. "

^^^ That being said,  how can you even know what the latest is versus what's installed?  And, would getting a new modem possibly come with better firmware?

[EG]

Even if you got a new modem with different factory-installed firmware, it would change to whatever Comcast is currently using as soon as it connects for the first time.