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 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
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
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.