Cisco DNCS System Release 2.7 3.7 4.2 Guide De Conception
1-20
Introducing DOCSIS
4000358 Rev B
DHCT Initialization
Introduction
This section describes how DOCSIS-capable DHCTs operating in Mixed
DOCSIS/DAVIC mode obtain the IP addresses for their cable modems and DHCT
CPEs during initialization. This section also addresses how these DHCTs
communicate their DHCT CPE IP address to the DNCS.
Obtain and Communicate IP Addresses
When the DOCSIS-capable DHCT boots in DOCSIS or Mixed DOCSIS/DAVIC
mode, the DHCP server assigns an IP address to the cable modem element and the
DHCT CPE.
After obtaining the IP addresses, the DHCT communicates the DHCT CPE IP
After obtaining the IP addresses, the DHCT communicates the DHCT CPE IP
address to the DNCS using DNCS UNConfig messages. The DNCS must send an
acknowledgement of receiving the IP address to the DHCT. Otherwise, the DHCT
continues to attempt to communicate the IP address to the DNCS until it receives an
acknowledgement.
The following table shows the communication exchange when IP addresses are
The following table shows the communication exchange when IP addresses are
delivered to DHCTs in DAVIC and DOCSIS or Mixed DOCSIS/DAVIC mode:
Message
DAVIC Mode
DOCSIS or Mixed
DOCSIS/DAVIC Mode
UNConfigRequest
The UNConfigRequest
message is sent from the
DHCT to the DNCS to
request an IP address.
The UNConfigRequest
message is sent from the
DHCT to the DNCS to
report its IP address that
was assigned by the
DHCP server.
UNConfigConfirm
The UNConfigConfirm
message is sent from the
DNCS to the DHCT to
deliver an IP address.
The UNConfigConfirm
message is sent from the
DNCS to the DHCT to
acknowledge receipt of the
UNConfigRequest
message.
The DHCT communicates its IP address to the DNCS when the DHCT initializes (or
boots) and when the IP address changes.