Completely stranger to DOCSIS enviroment, I have question about IP addressing and perhaps how DHCP is setup in this network.
I was checking my cable modem/router (COX subscriber) and noticed my IP with subnet mask of /21 on WAN interface. How is traffic passed from my modem/router to another customer modem/router from the same subnet? I am sure it's not a bridged network as it's not secure to allow direct layer2 between customer modem/routers.
Trace routing from my IP to another IP on the same network on WAN interface, I see a 10.x.y.z router in between! It could be secondary IP on my modem/router that I can't see?
How traffic between two modems having IPs from same /21 network is managed in DOCSIS enviroment? Or may be it's not DOCSIS specific.
Perhaps it's proxy-arp in place on CMTS. I need someone confirm it please