Cisco DNCS System Release 2.7 3.7 4.2 テクニカルリファレンス
Operations Alert Bulletin
Limitations on Headend IP Addresses
for Set-Tops in DOCSIS Mode
Limitations on Headend IP Addresses
for Set-Tops in DOCSIS Mode
Background
Engineers at Cable Television Laboratories, Inc. (CableLabs®) have reserved the
192.168.100.1 IP address for diagnostic purposes for cable modems. Because
CableLabs did not specify a subnet mask, Cisco chose 255.255.255.0, the Internet
standard for a Class C IP address.
If a headend server is assigned an IP address in the 192.168.100.0/24 subnet, then
If a headend server is assigned an IP address in the 192.168.100.0/24 subnet, then
neither the cable modem nor the set-top itself will be able to communicate with the
headend server, resulting in possible service outages. Examples of headend servers
include the Digital Network Control System (DNCS), the video-on-demand (VOD)
server, the Dynamic Host Configuration Protocol (DHCP) server, and the Trivial File
Transfer Protocol (TFTP) server.
Recommendation
System operators must avoid assigning an IP address in the 192.168.100.0/24 subnet
to any headend server. Any headend servers that currently have an IP address in the
192.168.100.0/24 subnet must be assigned a new IP address. Furthermore, no set-top
or cable modem can be assigned an IP address in the 192.168.100.0/24 subnet, either.
Note: Set-tops that operate in DAVIC mode are not affected by this limitation.
Note: Set-tops that operate in DAVIC mode are not affected by this limitation.