Lucent Technologies 6000 - Manual (Page 420)

9-56 MAX 6000/3000 Network Configuration Guide
Configuring IP Routing
Configuring IP routes
Dynamic routes
A dynamic route is a path, to another network, that is learned from another IP router rather than
configured in one of the MAX unit’s local profiles. A router that uses RIP broadcasts its entire
routing table every 30 seconds, updating other routers about the usability of particular routes.
Hosts that run ICMP can also send ICMP Redirects to offer a better path to a destination
network. OSPF routers propagate link-state changes as they occur. Routing protocols such as
RIP and OSPF all use some mechanism to propagate routing information and changes through
the routing environment.
Route preferences and metrics on a MAX unit
A MAX unit supports configurable route preferences, because different protocols have
different criteria for assigning route metrics. For example, RIP is a distance-vector protocol,
which uses a real or virtual hop count as a metric to select the shortest route to a destination
network. OSPF is a link-state protocol, which employs a variety of link conditions, such as the
reliability or speed of the link, as a metric to determine the best path to a destination network.
When choosing a route to put into the routing table, the router first compares preference
values, preferring the lowest number. If the preference values are equal, the router compares
the metric fields and uses the route with the lowest metric. Following are the preference values
for the various types of routes:
Note: You can configure the DownMetric and DownPreference parameters (located in the
Connection profile’s IP Options subprofile) to assign different metrics and preferences,
respectively, to routes on the basis of whether the routes are in use or are down. You can direct
the unit to use active routes, if available, rather than routes that are down.
Static route configuration
This section shows how to configure the default static route, define a static route to a remote
subnet, and make sure that the MAX uses a static route before a RIP route.
Settings in a Static Route profile
For sample Connection profile configurations, see “Configuring WAN interfaces” on
page 9-31. Each of the configurations shown in that section results in a static route. For an
example of the Ethernet > Mod Config profile configuration of the MAX unit’s local IP
interface, see “Configuring routing table updates” on page 9-8.
Route Default
preference
Directly connected 0
OSPF 10
CMP 30
RIP 100
Static 100
ATMP, PPTP 100