Cisco cBR 8 User Manual

For example, if you set MAX CPE to 2, a customer could use their cable modem to connect a maximum of
two CPE devices (two MAC addresses) to the cable network. A customer could choose to connect two PCs
simultaneously to their cable modem and use both to access the network.
However, if the customer then disconnected these PCs and connected two new PCs, the cable modem would
not allow the new PCs to come online, because they would be the third and fourth MAC addresses that are
connected to the cable modem. The customer would have to reset the cable modem before being able to use
the new PCs.
The MAX CPE value, if present, must be a positive integer in DOCSIS 1.0 configuration files. This
parameter can be zero in DOCSIS 1.1 configuration files, but if so, the cable modem uses a MAX CPE
value of 1. If the MAX CPE parameter is not present in either type of DOCSIS configuration file, it defaults
to 1.
Note
MAX Host
The MAX Host parameter is an optional parameter and is configured on the Cisco CMTS and specifies the
maximum number of CPE devices (MAC addresses) that the CMTS will allow to have network access. You
can control this parameter for individual cable modems, for all cable modems on a particular cable interface,
or for all cable modems on the Cisco CMTS, depending on the CLI command being used:
• cable modem max-cpe—Configures MAX Host for all cable modems on the Cisco CMTS. You can
use the unlimited keyword to specify that the Cisco CMTS should not enforce a MAX Host limit for
cable modems.
When this is enabled, the Cisco CMTS learns a MAC address the first time that the CPE device accesses the
cable network. After the Cisco CMTS has logged the maximum number of MAC addresses specified by a
MAX Host parameter, it drops all traffic from CPE devices that have any other MAC address.
In DOCSIS 1.1 cable networks, when both the MAX CPE IP and MAX Host parameters are configured,
the Cisco CMTS uses the lesser value to determine the maximum number of CPE devices that are allowed
behind each cable modem. By default, MAX Host is set to 16.
Tip
The entire MAX Host address table is cleared whenever the Cisco TS is reset. You can also clear an entry
for a particular CPE device using the clear cable host command.
Note
Specifying an Unlimited Value for Max Host
The cable modem max-cpe command, which affects all cable modems on the CMTS, supports the unlimited
keyword, which specifies that the CMTS should not enforce any limit on CPE devices. When you configure
the CMTS with the unlimited keyword, this setting, you are allowing cable modems to support any number
of CPE devices.
Do not use the unlimited option without also specifying the proper value for MAX CPE in the DOCSIS
configuration file, so that each cable modem can control the maximum number of CPE devices it supports.
In addition, to prevent users from requesting an unlimited number of IP address, be sure to configure the
Cisco cBR Series Converged Broadband Routers Troubleshooting and Network Management Configuration
Guide for Cisco IOS XE Fuji 16.8.x
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Maximum CPE and Host Parameters
MAX Host

Cisco cBR 8 Specifications

General

Brand	Cisco
Model	cBR 8
Category	Network Router
Language	English