Allied Telesis AT-S63 - Manual (Page 314)

Chapter 27: Internet Protocol Version 4 Packet Routing
314 Section VII: Routing
Routing Table
The switch maintains its routing information in a table of routes that tells
the switch how to find a local or remote destination. Each route is uniquely
identified in the table by its IP address, network mask, next hop, protocol,
and routing interface.
When the switch receives an IPv4 packet, it scans the routing table to find
the most specific route to the destination on an “up” interface where there
is at least one active port in the VLAN. If the switch does not find a direct
route to the remote destination and no default route exists, the switch
discards the packet and sends an ICMP message to that effect back to the
source.
The switch transmits its routing table every thirty seconds from those
interfaces that have RIP. The RIP timer is not adjustable. The switch also
transmits its routing table and resets the timer to zero whenever there is a
change to the table to ensure that the neighboring routers are immediately
informed of updates to the table.
Dynamic RIP routes are removed from the table when they are not kept up
to date (refreshed) by the neighboring routers. The metric of a route that is
not refreshed is increased to 16 to indicate an unreachable network. If the
route is not updated after 180 seconds, it is deleted from the table.
The maximum storage capacity of the routing table in the AT-9400 Switch
is:
ˆ 512 interface routes
ˆ 1024 static routes
ˆ 1024 RIP routes