Allied Telesis AT-8550 - Manual (Page 131)

AT-9108, AT-8518, AT-8525, and AT-8550 User’s Guide
8-3
Populating the
Routing Table
The switch maintains an IP routing table for both network routes and
host routes. The table is populated from the following sources:
❑ Dynamically, by way of routing protocol packets or by ICMP
redirects exchanged with other routers
❑ Statically, by way of routes entered by the administrator
— Default routes, configured by the administrator
— Locally, by way of interface addresses assigned to the
system
— By other static routes, as configured by the
administrator
Note
If you define a default route, and subsequently delete the VLAN on
the subnet associated with the default route, the invalid default route
entry remains. You must manually delete the configured default
route.
Dynamic Routes. Dynamic routes are typically learned by way of RIP
or OSPF. Routers that use RIP or OSPF exchange information in their
routing tables in the form of advertisements. Using dynamic routes,
the routing table contains only networks that are reachable.
Dynamic routes are aged out of the table when an update for the
network is not received for a period of time, as determined by the
routing protocol.
Static Routes. Static routes are manually entered into the routing
table. Static routes are used to reach networks not advertised by
routers. You can configure up to 64 static unicast routes on the
switch.
Static routes can also be used for security reasons, to control which
routes you want advertised by the router. You can decide if you want
all static routes to be advertised, using one of the following
commands:
[enable | disable] rip export static
[enable | disable] ospf export static
The default setting is enabled. Static routes are never aged out of the
routing table.