Cisco Broadband Cable Command Reference Guide

Cisco CMTS Features
Table 1-3 Principle Software Features
1-4
Cisco Broadband Cable Command Reference Guide
Chapter 1 Overview
Feature Category Item
Packet Filtering Options Ability to filter packets that are not IP or ARP, based on the EtherType/SAP/SNAP value
in the Ethernet header?
Ability to filter packets based on the PROTOCOL field in the IP header (e.g., NETBIOS
over IP traffic)?
Ability to filter packets based on the combination of IP address, upper-layer protocol
(e.g., UDP, TCP, ICMP) and upper-layer protocol’s port number or ICMP type in the IP
packet
Ability to configure source IP address filtering on RF subnets to prevent subscribers
from using source IP addresses not valid for the IP subnet they are physically connected
to
Per modem filters (per CM/host access lists)—ability to filter incoming packets from
individual hosts or CMs based on the source MAC or IP address; allows lists to be
specified on a per-interface and per-direction basis
Cable monitor—ability to filter a selection of MAC messages, map messages, and data
packets to access lists, MAC address and upstream port numbers; enable time stamping
of each packet, and permit the option of stripping away the DOCSIS header for data
packets; this increases the CMTS administrator’s ability to manage network variables,
understand network issues that can affect application performance and functionality, and
make it easier to resolve interoperability problems
Provisioning and Maintenance
Options
DHCP client ID/remote ID options to limit the number of CPE devices per CM
“Command max-CPE configuration file entry override”—allows the CMTS
administrator to override a CM’s DOCSIS configuration file setting that specifies the
maximum number of CPE devices the CM supports
DHCP CM host ID (CM & host subnet addressing) to modify the giaddr field of
DHCPDISCOVER packets based on whether the source is a CM or a host to help verify
addresses
Upstream address verification—verifies CM and PC addresses to ensure CM SID and
MAC addresses are consistent; this helps ensure addresses are not spoofed; CMTS
administrator can determine the IP and MAC address of a given CM & the SID number
that shows the IP and MAC addresses of all devices learned in the CM’s MAC table.
Using customer databases, the adm inistrator can cross reference the spoofing CM and
PC and prevent use
Enhanced source address verification—verifies that each upstream data packet from a
CM comes from the source IP address in the packet known to be associated with the CM
Dynamic mobile hosts—allows the CMTS administrator to bring up a PC behind one
CM, then move it to another CM; software maintains host information in tables; supports
“pinging” the host using the old SID to verify that the CM has indeed been moved
Dynamic ranging support—adds an intermediate “reset” state to the CM State List (i.e.,
show cable modem) that identifies CMs ranging, responding, failing to respond, and
being deprovisioned after the CM has failed to respond for a period of time; instead of
removing the service identifier (SID) of a CM having problems, the CM is put into a
reset, ranging request state for a few seconds before it is marked “offline” when it fails
to register
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