Chapter 15: Interface IP Configuration
STANDARD Revision 1.0
C4® CMTS Release 8.3 User Guide
© 2016 ARRIS Enterprises LLC. All Rights Reserved.
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Per interface cable source-verify
VRF forwarding
Device classification
The DHCP Relay Agent supports the definition of 10 DHCP Server IP addresses per subinterface.
The DHCP Relay Agent classifies ingress CM DHCP packets to the lowest numbered subinterface associated for each
unique DHCP Server IP address.
When the DHCP Relay Agent is forwarding a packet originating from a CPE, it will forward the packet using as its giaddr
the primary or a secondary address, depending on the dhcp-giaddr mode of the subinterface, that is, of the
subinterface associated with the CM that the CPE is behind. The packet will be forwarded to each unique DHCP server
IP address for CPEs provisioned on that subinterface.
If there are no DHCP servers for CPEs defined for the subinterface associated with the CM that a CPE is behind, then
the DHCP Relay Agent will forward a packet originating from a CPE to each unique DHCP server IP address for CPEs
using as its giaddr the primary address or a secondary address, depending on the dhcp-giaddr mode of the
subinterface, in other words, the lowest numbered subinterface provisioned with that server address.
This allows MSOs to provide a service where different CPEs behind a single cable modem could be serviced by different
ISPs on different subinterfaces. It would require the C4/c CMTS to be provisioned such that the CMs and CPE would be
on different subinterfaces. In addition, it provides a mechanism where different giaddrs could be sent to different
DHCP servers by defining those DHCP servers on different subinterfaces.
The subinterfaces for CMs would be provisioned with DHCP servers marked for use with CMs only, and the
subinterfaces for CPEs would be provisioned with DHCP servers marked for use with CPEs only (although DHCP server
addresses could be the same values).
Subinterfaces cannot be defined for SCM ports.
Network ACLs
For information on configuring network ACLs, see the see "
(page 950) chapter.