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Cisco Broadband Cable Command Reference Guide
OL-1581-08
Chapter 3 Cisco CMTS Show Commands
show cable arp-filter
The following example shows how to display the devices that are generating or filtering more than 10
ARP requests for IP packets per reporting period. Repeat the command to see how quickly the device is
generating ARP packets.
Router#
show cable arp-filter c3/0 ip-requests-filtered 10
Sid MAC Address IP Address Req-Filtered Req-For-IP-Filtered Rep-Filtered
2 0006.2854.71e7 50.3.72.4 0 1926 0
Router#
Table 3-3
describes the fields shown in the display.
Clearing the ARP Packet Counters
The following example shows the cable ARP counters being cleared by the
clear counters cable
interface
command. This can be useful because the ARP counters are 16-bit counters that can wrap
around to zero relatively quickly when large amounts of ARP traffic is being generated. Also, the ARP
packet counters could include SIDs that had forwarded large amounts of ARP traffic in the past, but that
are not currently forwarding such traffic. Clearing the counters allows you to clearly see the SIDS that
are currently forwarding the ARP traffic that is triggering the ARP filters.
Router#
show cable arp cable 3/0
ARP Filter statistics for Cable3/0:
Replies Rcvd: 3278 total. 84 unfiltered, 3194 filtered
Requests Sent For IP: 941 total. 30 unfiltered, 911 filtered
Requests Forwarded: 941 total. 37 unfiltered, 904 filtered
Router#
show cable arp-filter cable 5/1/0 requests-filtered 10
Sid MAC Address IP Address Req-Filtered Req-For-IP-Filtered Rep-Filtered
1 0006.2854.72d7 10.3.81.4 8 0 0
23 0007.0e02.b747 10.3.81.31 32 0 0
57 0007.0e03.2c51 10.3.81.31 12407 0 0
...
81 00C0.c726.6b14 10.3.81.31 23 0 0
Router#
clear counter cable 5/1/0
Clear "show interface" counters on this interface [confirm]
y
08:17:53.968: %CLEAR-5-COUNTERS: Clear counter on interface Cable5/1/0 by console
Table 3-3
show cable arp-filter Detail Field Descriptions
Field Description
SID
Service ID (SID) of the device.
MAC Address
Hardware (MAC-layer) address of the cable modem or CPE device.
IP Address
IP address of the cable modem or CPE device.
Req-Filtered
Total number of ARP requests that the device has generated or forwarded.
Req-For-IP-Filtered
Total number of ARP requests that the device has generated or forwarded for
IP packets.
Rep-Filtered
Total number of ARP replies that the device has generated or forwarded.
Note
The Req-Filter and Rep-Filtered counters are 16-bit counters, with a maximum value of 65,535
packets. If the number of packets exceeds this amount, the counter wraps back to zero and
begins incrementing again.