How to Reduce Address Resolution Protocol Table Size with the Active-Arp Option

Asset ID:	1-79-1598813.1
Update Date:	2017-04-04
Keywords:

Solution Type Predictive Self-Healing Sure

Solution 1598813.1 : How to Reduce Address Resolution Protocol Table Size with the Active-Arp Option

Applies to:

Acme Packet 4500
Net-Net 3810
Acme Packet 3820
Acme Packet 4600
Acme Packet 6100
Acme Packet OS

Purpose

Reducing ARP (Address Resolution Protocol) table size with active-arp option in the Oracle AP Session Border Controller.

Details

Reducing ARP (Address Resolution Protocol) table size with active-arp option in the Oracle AP Session Border Controller.

active-arp is a configuration option in the AP Session Border Controller that restricts entries written to the ARP cache to only remote hosts configured on the SBC as either network addresses or gateways. Thus, it provides protection against exhaustion of the ARP table as a result of a malicious or non-malicious storm of gratuitous ARP requests.

Note that if a remote device successfully pings the SBC, then its entry will be written to the ARP cache even with this option enabled. active-arp only guards against gratuitous ARPs

active-arp is configured as an option in the media-manager configuration container.

Configuration Example

SD# conf t
SD(configure)# media-manager
SD(media-manager)# media-manager
SD(media-manager-config)# sel
SD(media-manager-config)# options active-arp
SD(media-manager-config)# done
media-manager
state enabled
latching enabled
flow-time-limit 86400
initial-guard-timer 300
subsq-guard-timer 300
tcp-flow-time-limit 86400
tcp-initial-guard-timer 300
tcp-subsq-guard-timer 300
tcp-number-of-ports-per-flow 2
hnt-rtcp disabled algd-log-level NOTICE
mbcd-log-level NOTICE
options active-arp
red-flow-port 1985
red-mgcp-port 1986
red-max-trans 10000
red-sync-start-time 5000
red-sync-comp-time 1000
media-policing enabled
max-signaling-bandwidth 10000000
max-untrusted-signaling 100
min-untrusted-signaling 30
app-signaling-bandwidth 0
tolerance-window 30
rtcp-rate-limit 0
min-media-allocation 32000
min-trusted-allocation 1000
deny-allocation 1000
anonymous-sdp disabled
arp-msg-bandwidth 32000
fragment-msg-bandwidth 0
rfc2833-timestamp disabled
default-2833-duration 100
rfc2833-end-pkts-only-for-non-sig enabled
translate-non-rfc2833-event disabled
last-modified-by admin@console
last-modified-date 2008-09-24 11:31:18

SD(media-manager-config)# exit

SD(media-manager)# exit

SD(configure)# exit

SD# save-config
Save-Config received, processing.
waiting 1200 for request to finish
Request to 'SAVE-CONFIG' has Finished,
Save complete
Currently active and saved configurations do not match!
To sync & activate, run 'activate-config' or 'reboot activate'.

SD# activate-config
Activate-Config received, processing.
waiting 120000 for request to finish
Request to 'ACTIVATE-CONFIG' has Finished,
Activate Complete

SD#

Important Notes

Note: RTC (real time configuration) does not support this option. Hence a reboot of the SBC is required to enable this functionality. The Administrator can check for its activation in the boot sequence of the SBC by searching for the following line: enable active ARP mode

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