Can someone give me a general concept if it's possible, or what mechanism can be used to cause eRouter traffic to match the cable bundle instead of sub-bundle?
Assuming you have a setup like so:
ip bundle 1
10.1.x.x !modems
X.1.X.X ! CPEs
X.2.X.X ! eRouter CPEs
cable helper 172.16.x.1 modem
cable helper 172.16.x.2 host
When the modem comes online, the DHCP server assigns it an IP from either the 10.1.x.x network or the 10.2.x.x network, usually whether it is authorized or not, Authorized going into 10.1.x.x and unauthorized going into 10.2.x.x
This is where it gets DHCP server specific.
in ISC DHCPd, it has a concept of Shared-Networks, and for the following to work, you need a separate Modem and CPE DHCP server.
so on your CPE DHCP server, you create a shared network with the following subnets
10.1.x.x - no pools defined
X.1.X.X
X.2.X.X
and any CPE that hits the DHCP server with a 10.1.x.x modem IP will get an CPE IP of X.1.X.X or X.2.X.X
Then you create a second shared-network
10.2.x.x - no pools defined
X.3.X.X
X.4.X.X
and any CPE that hits the DHCP server with 10.2.x.x modem IP will get an CPE of X.3.X.X or X.4.X.X
When the CMTS forwards the DHCP from the CPE (eRouter) it sets it's source address to the primary address of the bundle/sub bundle, the modem received an ip from. This is how you can exploit moving CPEs from one bundle to the other.
Some of it is DHCP dependent, but the gist is:
Assuming you have a setup like so:
ip bundle 1
10.1.x.x !modems
X.1.X.X ! CPEs
X.2.X.X ! eRouter CPEs
cable helper 172.16.x.1 modem
cable helper 172.16.x.2 host
ip bundle 1.1
10.2.x.x !modems
X.3.X.X !CPEs
X.4.X.X !eRouter CPEs
cable helper 172.16.x.1 modem
cable helper 172.16.x.2 host
When the modem comes online, the DHCP server assigns it an IP from either the 10.1.x.x network or the 10.2.x.x network, usually whether it is authorized or not, Authorized going into 10.1.x.x and unauthorized going into 10.2.x.x
This is where it gets DHCP server specific.
in ISC DHCPd, it has a concept of Shared-Networks, and for the following to work, you need a separate Modem and CPE DHCP server.
so on your CPE DHCP server, you create a shared network with the following subnets
10.1.x.x - no pools defined
X.1.X.X
X.2.X.X
and any CPE that hits the DHCP server with a 10.1.x.x modem IP will get an CPE IP of X.1.X.X or X.2.X.X
Then you create a second shared-network
10.2.x.x - no pools defined
X.3.X.X
X.4.X.X
and any CPE that hits the DHCP server with 10.2.x.x modem IP will get an CPE of X.3.X.X or X.4.X.X
When the CMTS forwards the DHCP from the CPE (eRouter) it sets it's source address to the primary address of the bundle/sub bundle, the modem received an ip from. This is how you can exploit moving CPEs from one bundle to the other.
Thank you very much for the thorough reply.