Chapter 20: CPE Device Classes
STANDARD Revision 1.0
C4® CMTS Release 8.3 User Guide
© 2016 ARRIS Enterprises LLC. All Rights Reserved.
652
Filter Group Assignment
Once the C4/c CMTS has classified a CPE it can assign specific filter groups to that device class on a per-subinterface basis
or on a system-wide basis. However, if an IPv4 modem has TLV 37 populated in its configuration file, then this information
takes precedence and determines the filter group information.
CPE Device Classes address the areas potentially impacted by multiple services behind a cable modem. One such need is to
use subscriber management cable packet filters for service-specific filtering of packets.
DOCSIS Subscriber Management MIB
The DOCSIS Subscriber Management MIB defines a mechanism for an C4/c CMTS to apply filters to a specific modem or
CPE device as a result of successful DOCSIS registration. In this way, different filters can be applied to different modems or
CPEs on the same cable interface and even within the same IP subnet.
One example of this is an eMTA with an Ethernet interface for data services. In this situation, an operator would want to
apply one set of filters to protect the eMTA and another set of filters for the data service.
Note: Filters are applied to a CPE device after it acquires its IPv4 address.
Assigning Filter Groups to CPE Devices
There are three ways in which a filter group can be assigned to a CPE device.
The TLV-37 in the CM config file may be used to indicate which filter groups to use for each specific device class type.
When used TLV-37 overrides all other provisioning.
Each cable subinterface may have the filter group assigned based on CPE device class type.
A system-wide default cable filter group may also be provisioned for each device type.
Rules for Applying Filter Groups
Some rules for applying filter groups based on device class are as follows:
You may only provision one device type per command.
There is no any but there is a host. If all cpe types are provisioned they will collapse to host in the C4/c CMTS
configuration.