Web Management Guide

Table Of Contents
Chapter 16
| General IP Routing
Address Resolution Protocol
– 523
The aging time determines how long dynamic entries remain in the cache. If
the timeout is too short, the router may tie up resources by repeating ARP
requests for addresses recently flushed from the table.
When a ARP entry expires, it is deleted from the cache and an ARP request
packet is sent to re-establish the MAC address.
Web Interface
To configure the timeout for the ARP cache:
1.
Click IP, ARP.
2.
Select Configure General from the Step List.
3.
Set the timeout to a suitable value for the ARP cache.
4.
Click Apply.
Figure 335: Configuring ARP Timeout
Configuring Static ARP
Addresses
For devices that do not respond to ARP requests or do not respond in a timely
manner, traffic will be dropped because the IP address cannot be mapped to a
physical address. If this occurs, use the IP > ARP (Configure Static Address – Add)
page to manually map an IP address to the corresponding physical address in the
ARP cache.
Command Usage
The ARP cache is used to map 32-bit IP addresses into 48-bit hardware (that is,
Media Access Control) addresses. This cache includes entries for hosts and
other routers on local network interfaces defined on this router.
You can define up to 128 static entries in the ARP cache.
A static entry may need to be used if there is no response to an ARP broadcast
message. For example, some applications may not respond to ARP requests or
the response arrives too late, causing network operations to time out.
Static entries will not be aged out or deleted when power is reset. You can only
remove a static entry via the configuration interface.