Allied Telesis AT-S63 User Manual

Page of 514
AT-S63 Management Software Features Guide
Section VII: Routing
323
Note
The AT-9408LC/SP, AT-9424T/GB, and AT-9424T/SP Switches do 
not use the ARP table to move packets through the switching matrix. 
They refer to the table only when they perform a management 
function requiring them to communicate with another network node.
Default Gateway
The default gateway specifies the IP address of an interface on a 
neighboring router. The switch’s management software uses this address 
as the next hop to reaching a remote network device, such as a remote 
Telnet, SSH, or web browser management workstation or a syslog server, 
when the switch’s interface and the remote device are on different 
subnets.
As an example, assume you wanted to manage the switch from a remote 
management workstation on a different subnet than the local interface, 
and needed the switch to access a RADIUS authentication server also on 
a different subnet. Here, you would need to define a default gateway on 
the switch so that the unit would know the next hop to reaching the remote 
workstation and the RADIUS server.
The default gateway is only used for management functions, such as 
communicating with a remote management workstation or sending events 
to a syslog server. The default gateway is not used during the normal 
Layer 2 switching of packets among the switch ports and, as such, is not 
necessary for normal operations of the device.
You define the default gateway by creating a default route on the switch. 
As explained in “Static Routes” on page 307, this type of route does not 
specify a destination address. Rather, it simply defines the IP address of 
the next hop, which becomes the default gateway for the switch.
The IP address of the next hop of the default route must be of the same 
subnet as the switch’s interface.