Cisco UBR924 - uBR 924 Router Troubleshooting Tips page 10

Step 2—Connect to the Cisco uBR924
.
Table 1
Sequence
1
2
3
4
5
6
7
8
9
10
Step 2—Connect to the Cisco uBR924
Telnet to the IP address assigned to the cable interface or Ethernet interface. If the interface is not
up, you will need to access the Cisco IOS software via the RJ-45 console port, which is a physical
port on the back of the Cisco uBR924.
Note
the cable service company prior to installation at the subscriber site.
10 Cisco IOS Release 12.0(5)T
Cable Modem Initialization Sequences and Events
Event
Scan for a downstream channel and
establish synchronization with the
CMTS.
Obtain upsteam channel parameters.
Start ranging for power adjustments. The ranging process adjusts the Cisco uBR924's transmit
Establish IP connectivity.
Establish the time of day.
Establish security.
Transfer operational parameters.
Perform registration.
Comply with baseline privacy.
Enter the operational maintenance
state.
For security purposes, the console port on the Cisco uBR924 may have been deactivated by
Description
The Cisco uBR924 acquires a downstream channel from the
CMTS and saves the last operational frequency in non-volatile
memory. The Cisco uBR924 tries to reacquire the saved
downstream channel the next time a request is made.
An ideal downstream signal is one that synchronizes
Note
QAM symbol timing, FEC framing, MPEG packetization, and
recognizes downstream sync MAC layer messages.
The Cisco uBR924 waits for an upstream channel descriptor
(UCD) message from the CMTS. The UCD provides
transmission parameters for the upstream channel.
power. Ranging is performed in two stages: ranging state 1 and
ranging state 2.
The Cisco uBR924 sends a DHCP request to obtain an IP
address, which is needed for IP connectivity. The DHCP
response also includes the name of a file that contains
additional configuration parameters, the TFTP server's
address, and the Time of Day (TOD) server's address.
The Cisco uBR924 accesses the TOD server for the current
date and time, which is used to create time stamps for logged
events (such as those displayed in the MAC log file).
Keys for privacy are exchanged between the Cisco uBR924
and the CMTS.
The Cisco uBR924 cable access router supports baseline
Note
privacy in Cisco IOS Release 12.0(5)T and later.
After the DHCP and security operations are successful, the
Cisco uBR924 downloads operational parameters from a
configuration file stored on the cable company's TFTP server.
The Cisco uBR924 registers with the CMTS. After it is
initialized, authenticated, and configured, the Cisco uBR924 is
authorized to forward traffic onto the cable network. .
If the software image running on the Cisco uBR924 includes
baseline privacy, link level encryption keys are exchanged
between the CMTS and the Cisco uBR924.
As soon as the Cisco uBR924 has successfully completed the
above sequence, it enters operational maintenance state.