Allied Telesis AT-S63 - Manual (Page 311)

AT-S63 Management Software Features Guide
Section VII: Routing 311
Default Routes
A default route is used when the switch cannot find a route in its routing
table for a packet that needs to be forwarded to a remote destination.
Rather than discard the packet, the switch sends it to the next hop
specified in the default route.
A default route has an destination IP address of 0.0.0.0 and no subnet
mask. A default route can be enter manually in the form of a static route or
learned dynamically through RIP. A switch can have multiple default
routes.