User's Manual

ARCXTEND USER MANUAL – R1.4, ISSUE 4
Copyright 2005 Arcwave, Inc. 75
Sequence Event Description
1
Scan for a downstream
channel and
establish synchronization
with the
CMTS.
The cable modem acquires a downstream channel
from the CMTS and saves the last operational
frequency in non-volatile memory. The cable
modem 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.
2
Obtain upstream channel
parameters.
The cable modem waits for an upstream channel
descriptor (UCD) message from the CMTS. The
UCD provides transmission parameters for the
upstream channel.
3
Start ranging for power
adjustments.
The ranging process adjusts the cable modem’s
transmit power.
4 Establish IP connectivity.
The cable modem 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 cable modem 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 cable
modem and the CMTS.
7
Transfer operational
parameters.
After the DHCP and security operations are
successful, the cable modem downloads
operational parameters from a configuration file
stored on the cable company’s TFTP server.
8
Comply with baseline
privacy.
If the software image running on the cable modem
includes baseline privacy, link level encryption
keys are exchanged between the CMTS and the
cable modem.
9
Enter the operational
maintenance state.
As soon as the cable modem has successfully
completed above sequence, it enters operational
maintenance state.
Table B-1 Cable Modem Initialization Steps