Certain cable modems will be unavailable from Cisco 10k CMTS. In principle, they are online, but they cannot be pinged, they do not respond to ip. However, if I try to "ping docsis MAC_ADDR", there will be an answer. After a modem restart, the tcp connection starts, but it only works for 10-20 minutes. :( Mostly affects modems, Arris type. If I replace cable modes with another one in the same place, it will work. :( What can cause such an error?
Regards!
What firmware version on the troublesome Arris modems?
What is the Init(xx) code? Do you see dhcp traffic at your server? Does the show cable modem macaddress show an IP or not?