Cisco Broadband Cable Command Reference Guide

Chapter 2 Cisco Cable Modem Termination System Commands
cable proxy-arp
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Cisco Broadband Cable Command Reference Guide
cable proxy-arp
To activate cable proxy Address Resolution Protocol (ARP) on the cable interface or subinterface, use
the cable proxy-arp command in cable interface or subinterface configuration mode. To disable this
feature, use the no form of this command.
cable proxy-arp
no cable proxy-arp
Syntax Description This command has no arguments or keywords.
Defaults Proxy APR service is enabled.
Command Modes Cable interface and subinterface configuration
Command History
Usage Guidelines This command enables or disables direct host-to-host communications over the same cable subnet.
Because the downstream and upstream are separate interfaces, CMs cannot directly perform address
resolution with other CMs on the cable plant. This means that the CMs must send all traffic through the
CMTS, even if the destination CM is on the same subnet.
The cable proxy-arp command enables the Cisco CMTS to act as a proxy for ARP requests generated
by the CMs, which allows CMs on the same cable subnet to communicate directly which each other,
without the traffic having to be routed first through the CMTS. The no cable proxy-arp command
disables this feature, preventing CMs on the same subnet from communicating with each other without
routing the traffic through the CMTS.
Examples The following example shows how to activate proxy ARP for host-to-host communications:
Related Commands
Release Modification
11.3 XA This command was introduced.
12.1(3a)EC The subinterface support was added.
router(config-subif)# cable proxy-arp
The following example shows how to activate proxy ARP for host-to-host communications, on the cable
subinterface:
router(config)# interface cable 6/0.1
router(config-subif)# cable proxy-arp
Command Description
cable arp Activates cable Address Resolution Protocol (ARP).
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