This topic drives me nuts from time to time. We receive calls from customers that they don't have internet, when the cable modem is fine. Remote rebooting of the cable modem has no affect.
This only happens with "wired" modems. We had one customer it would happen to them at 5 minutes on the dot. I believe it is related to load balancing as when I mess with it, it seems to go away, but I can't find a way to log LB moves so I can go back and find exactly what happened.
Further testing shows if I have them repower just their router it comes back online. Which from a layer2 ethernet level this makes absolutely no sense as to why the cable modem wouldn't allow layer2 traffic due to a simple channel change when I believe it IS allowing traffic. I thought oh they aren't getting dhcp, but no it's not event that. I can't see the mac address of the CPE until they repower their equipment. It's random what customers this happens to, and the other people in the office don't understand this level of diagnostic so they truck roll only to be disapointed they can't fix it.
Ideas? I have all of our cmts's doing modem load-balancing only, no dynamic. We are pushing out more D3, should I just say screw it and go ALL D3 modems?
Thanks
questions:
when you say "repower their router", you mean a device connected to the modem, right?
also, are you looking at the CPE mac address at the CM, CMTS or both?
We had similar issues long time ago, it was related with the max-cpe config on the CMTS. Also, some newer modems expire the ARP table automatically, while others never expire it. Another potential issue is the CPE generating more than one DHCP requests, or something related with IPv6.
Just guessing for now ...
The issue only happens to D2 modems?
With your D2 load-balance, what init-tech methods have you specified? I have been using "2-4" with good success.
For a customer that is reporting no internet, "show cable modem xxxx.xxxx.xxxx cpe" has no cpe entry showing?
On your bundle, are you using cable source-verify ?
The affected customers are online OK for a while, and then the internet randomly stops? Or never worked since the modem came online.
How long is your CPE DHCP lease time?
What IOS version on CMTS?