Allied Telesis AT-S63 User Manual

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Chapter 27: Internet Protocol Version 4 Packet Routing
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Section VII: Routing
AT-9408LC/SP AT-9424T/GB, and AT-9424T/SP Switches
The AT-9408LC/SP, AT-9424T/GB, and AT-9424T/SP Switches do not 
support the IPv4 packet routing feature. They do, however, support a 
limited version of some of the features.
Local Interface
You can create one routing interface to provide support for those 
management features that require the switch to have an IP address. 
Furthermore, the interface can be designated as the local interface so that 
the switch can function as the master switch of an enhanced stack or for 
remote Telnet, SSH, or web browser management. For further 
information, refer to “Routing Interfaces and Management Features” on 
page 318.
ARP Table
These switches also have an ARP table with a maximum capacity of ten 
ARP entries. The table and entries are used by the AT-S63 Management 
Software when it performs a management function that requires it to 
communicate with another device on the network. An example would be if 
you instructed the switch to ping another network device or download a 
new AT-S63 image file or configuration file from a TFTP server.
The value of the ARP table is that it eliminates the need of the switch to 
issue unnecessary ARP broadcast packets when performing some 
management functions. This can improve the switch’s response time as 
well as reduce the number of broadcast packets on your network.
There are two types of entries. One type is permanent. There is only one 
permanent entry and it is used by the switch for internal diagnostics. It can 
never be removed from the table.
The other type is a temporary entry, of which there can be up to nine. The 
switch adds a temporary entry whenever its management software 
interacts with another network device during a management function. 
When you enter a management command that contains an IP address not 
in the table, the switch sends out an ARP broadcast packet. When the 
remote device responds with its MAC address, the switch adds the 
device’s IP address and MAC address as a new temporary entry to the 
table.
A temporary entry remains in the table only while active. An entry remains 
active so long as it is periodically used by the switch for management 
functions. If an entry is inactive for a defined period of time known as the 
ARP cache timeout, it is automatically removed from the table. To adjust 
this value, refer to the SET IP ARP TIMEOUT command. The default is 
150 seconds. If the table becomes full, the management software 
continues to add new entries by deleting the oldest entries.