System information

BSR 64000 Configuration and Management Guide
6-2
• Enabling Host Authorization for All CMs
• Creating a Static Host Authorization Entry for a Specific CM
• Enabling Host Authorization for an IP Range of CPEs
• Using DHCP Lease Query Function to Secure Cable Network
• Setting ARP Parameters
Setting the IP DHCP Relay Functions
The IP DHCP relay function is used to forward DHCP messages between clients and
servers. The IP DHCP relay agent function gathers broadcast DHCP discovery
packets from a Multimedia Terminal Adapter (MTA) device, cable modem (CM), or
Customer Premises Equipment (CPE), and forwards the packets to their
corresponding DHCP server. The DHCP relay function enables an MTA, CM, or CPE
to obtain an IP address from a DHCP server through the DHCP relay agent, which is
the router (SRM) between the cable interface and the DHCP server.
The ip dhcp relay information command enables the BSR’s DHCP relay agent to
insert the Spectrum Group Name that DHCP client belongs to and/or inserts the MAC
address of the DHCP client and the DOCSIS Device Class Identifier into outbound
requests to the DHCP server. The DOCSIS Device Class Indenter is only supported
for 1.1 CMs. Support for DHCP Option 82, sub-option 2 (Agent Remote ID) and
sub-option 4 (DOCSIS Device Class Identifier) is enabled by the ip dhcp relay
information option command. Support for DHCP Option 82, sub-option 85
(Spectrum Group Name) is enabled by the ip dhcp relay information
spectrum-group-name. The no ip dhcp relay agent information command disables
the insertion of DHCP Option 82, sub-options.
The following steps outline the IP DHCP relay process:
1. An MTA device, CM, or CPE sends broadcast DHCP discover packets to the
DHCP relay agent containing a request for an IP address.
2. The DHCP relay agent inserts the MTA, CM, or CPE option into the DHCP
discover packets. This option contains either the spectrum group name and
associated MAC address or a MAC address.
3. The DHCP relay agent inserts any configured options into the DHCP discover
packets. This can be a spectrum group name, a MAC address and a DOCSIS
Device Class Identifier or both the spectrum group name and the MAC address
and DOCSIS Device Class Identifier.