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cable arp
cable arp
To activate cable Address Resolution Protocol (ARP), use the cable arp command in cable interface or
subinterface configuration mode. To block ARP requests for CMs, use the no form of this command.
Syntax Description
This command has no arguments or keywords.
Defaults
ARP enabled
Command Modes
Cable interface and subinterface configuration
Command History
Release
12.1T
12.0(6)SC
12.1(2) EC1
12.1(3a)EC
12.2(8)BC1
Usage Guidelines
ARP is an Internet protocol used to map IP addresses to MAC addresses on computers and other
equipment installed in a network. You must activate ARP requests so that the Cisco CMTS can perform
IP address resolution on the downstream path.
Occasionally, you might want to use the no cable arp and clear arp-cache commands to block out new
ARP requests and clear the existing ARP table. In this situation, the Cisco CMTS will retain the ARP
addresses of currently online CMs (CMs with a known IP address) and will continue to send ARP
requests for those CMs when those ARP entries time out or are cleared, so that those CMs can continue
to remain online. ARP requests for CMs that are currently offline and for any other unknown IP
addresses, however, will remain blocked until ARP requests are reenabled on the downstream using the
cable arp command.
Using the no cable arp and
Note
of the IP addresses used by CMs and CPE devices to the DHCP server and provisioning system.
Cisco Broadband Cable Command Reference Guide
2-14
cable arp
no cable arp
Modification
This command was introduced.
This command was supported.
This command was supported.
Subinterface support was added.
Interaction with the clear arp-cache command was changed. Previously, the
clear arp-cache command sent an ARP request to a CM before clearing its
ARP entry. Now, the clear arp-cache command clears the ARP entry
without communicating with the CM. The CM (or its CPE devices) must
send one or more IP packets to the CMTS before IP communications can be
restored (assuming the CM or CPE devices are authorized to connect to the
network).
no cable proxy-arp
Chapter 2
Cisco CMTS Configuration Commands
commands shifts all responsibility for the management
OL-1581-08
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