Routing
140
6.3
 
ARP
RM Web
Release
 
6.0
 
07/2010
6.3.1 Setting ARP parameters 
Parameter Meaning Possible 
Values
Default Setting
Aging Time With “Aging Time” you specify the time for 
which an entry remains before being 
deleted from the table. If there is a data 
transfer with the device within this time 
period, then the time measuring begins 
from the start again. 
15-21600 s 1200
Response Time With “Response Time” you specify how 
long ARP waits for a response before the 
query is seen to have failed.
1-10 1
Retries With “Retries” you specify how often ARP 
repeats a failed query before stopping the 
query to this address.
0-10 4
Cache Size “Cache Size” enables you to limit the 
maximum number of entries in the table. 
When the maximum number is reached, 
ARP deletes the oldest entry.
PowerMICE: 
192-2112 
MACH 4000: 
212-2132 
MACH 4000 
24/48G: 
212-3584
Maximum
Dynamic Renew When the “Dynamic Renew” is switched 
on, ARP starts a new query to a device for 
which the entry has exceeded the aging 
time. If this query is not answered, the 
Switch removes the entry from the table.
on/off on
Selective 
Learning
In the default setting, the router learns ARP 
entries passively. This means that the 
router receives all ARP requests and 
automatically learns the IP/MAC address 
assignment of the sending device. The 
automatic learning of all connected devices 
means that time-consuming ARP queries 
are excluded if the router has to send a 
data packet to an unknown device. In this 
case, the ARP tables may also be filled with 
unnecessary ARP entries (e.g. from 
devices that only wish to communicate 
locally). 
If “Selective Learning” is activated, then the 
router only learns the source IP/MAC 
address assignment if the ARP request 
was directed to the router itself (i.e. if the 
router address was explicitly queried).
on/off off
Table 51: ARP parameters