Cisco DNCS System Release 2.8.1 3.8.1 4.3.1 Design Guide
4000358 Rev B
Introducing DOCSIS
1-21
DHCT Initialization,
Continued
The DNCS distinguishes between DAVIC DHCTs that obtain their IP addresses from
the DNCS, and DOCSIS DHCTs that obtain their IP addresses from other servers.
This distinction is embedded in the UNConfigRequest message sent from the DHCT
to the DNCS. The DOCSIS DHCT includes its IP address in the message, whereas the
DAVIC DHCT does not.
PC applications receive IP data through the DOCSIS channel as soon as cable
PC applications receive IP data through the DOCSIS channel as soon as cable
modem registration is complete. Advanced DHCT services, such as VOD, that
require registration with the DNCS become available only after the DHCT receives
the UNConfigConfirm message from the DNCS.
Communication Exchange
The following three illustrations show the communication exchange among the
network components for the three communication modes:
•
•
DAVIC
•
Mixed DOCSIS/DAVIC
•
DOCSIS