Step 2—Connect to the Cisco uBR924

.

Table 1

Cable Modem Initialization Sequences and Events

 

 

 

Sequence

Event

Description

 

 

 

1

Scan for a downstream channel and

The Cisco uBR924 acquires a downstream channel from the

 

establish synchronization with the

CMTS and saves the last operational frequency in non-volatile

 

CMTS.

memory. The Cisco uBR924 tries to reacquire the saved

 

 

downstream channel the next time a request is made.

Note An ideal downstream signal is one that synchronizes QAM symbol timing, FEC framing, MPEG packetization, and recognizes downstream sync MAC layer messages.

2Obtain upsteam channel parameters. The Cisco uBR924 waits for an upstream channel descriptor (UCD) message from the CMTS. The UCD provides transmission parameters for the upstream channel.

3Start ranging for power adjustments. The ranging process adjusts the Cisco uBR924’s transmit power. Ranging is performed in two stages: ranging state 1 and ranging state 2.

4

Establish IP connectivity.

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.

 

 

 

5

Establish the time of day.

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).

 

 

 

6

Establish security.

Keys for privacy are exchanged between the Cisco uBR924

 

 

and the CMTS.

 

 

Note The Cisco uBR924 cable access router supports baseline

 

 

privacy in Cisco IOS Release 12.0(5)T and later.

 

 

 

7

Transfer operational parameters.

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.

 

 

 

8

Perform registration.

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. .

 

 

 

9

Comply with baseline privacy.

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.

 

 

 

10

Enter the operational maintenance

As soon as the Cisco uBR924 has successfully completed the

 

state.

above sequence, it enters operational maintenance state.

 

 

 

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 For security purposes, the console port on the Cisco uBR924 may have been deactivated by the cable service company prior to installation at the subscriber site.

10Cisco IOS Release 12.0(5)T

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Cisco Systems UBR924 manual Connect to the Cisco uBR924, Cmts