Max Cpe - Cisco cBR-8 Configuration And Troubleshooting Manual

Maximum CPE and Host Parameters
In addition, the DOCSIS configuration file contains a Network Access parameter that specifies whether
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the CPE devices behind the cable modem can access the cable network. If the Network Access parameter
is set to Disabled, no CPE devices behind a cable modem are able to access the network.
Also, the Cisco CMTS lists offline cable modems in its internal database for 24 hours. The CMTS does
Tip
not reset the CPE counts for these offline cable modems until the 24 hour period expires and the cable
modems come back online. If the cable modems come back online before the 24 hour period expires, the
CMTS continues to use the existing CPE counts.
All of these methods are similar in purpose, but they are configured differently and have a different impact
on cable modems and their CPE devices.
The cable modem enforces the MAX CPE value, the CMTS enforces the MAX Host, MAX CPE IP, and
MAX CPE IPv6 values.
The MAX CPE parameter provides Layer 2 control of CPE devices. The MAX CPE IP and MAX CPE
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IPv6 parameters provide Layer 3 control of CPE devices. The two methods are complimentary but not
otherwise related.

MAX CPE

The MAX CPE is a required parameter and used to control the number of CPE devices that can access the
network during the current session. In DOCSIS 1.0 cable networks, the MAX CPE parameter is the primary
means of controlling the number of CPE devices that can connect to the cable network using any particular
cable modem. This parameter is configured in the DOCSIS configuration file (TLV 18). If this parameter is
not specified in the DOCSIS configuration file, it defaults to a value of 1.
In DOCSIS 1.1 cable networks, the CMTS ignores the MAX CPE parameter that is specified in the
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DOCSIS configuration file, and uses the MAX Host parameter instead.
Each time a new CPE device attempts to connect to the cable network, the cable modem logs the hardware
(MAC) address. If the cable modem has not reached the MAX CPE number of MAC addresses, the new CPE
device is allowed to access the network. If the cable modem has reached the MAX CPE limit, it drops the
traffic from any additional CPE devices.
By default, the cable modem learns new MAC addresses on a first-come, first-served basis. You can also
preconfigure the allowable MAC addresses for CPE devices by entering those MAC addresses in the DOCSIS
configuration file (TLV 14). These cable modem gives these preconfigured MAC addresses preference in
connecting to the network.
The DOCSIS specification does not allow cable modems to age out MAC addresses, so a MAC address stays
in the log table of the cable modem until the cable modem is reset. You should therefore think of this parameter
as specifying the maximum number of CPE devices that can connect during any particular session, instead
of the maximum number of CPE devices that can simultaneously connect to the cable network.
Cisco cBR Series Converged Broadband Routers Troubleshooting and Network Management Configuration Guide
MAX CPE
for Cisco IOS XE Fuji 16.8.x
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