User`s guide

9-16 Preliminary November 23, 1998 MultiVoice Gateway for the MAX— User’s Guide
Configuring OSPF Routing
Administering OSPF
The following example shows how to configure a static route for OSPF to advertise a
third-party gateway:
1 Open a static route in Ethernet > Static Rtes.
2 Set Third-Party to Yes.
3 Set the Gateway to the forwarding address.
Ethernet
Static Rtes
Name=third-party
Silent=No
Active=Yes
Dest=10.212.65.0/24
Gateway=101.2.3.4
Metric=3
Preference=100
Private=No
Ospf-Cost=1
LSA-Type=Type1
ASE-tag=c00000000
Third-Party=Yes
4 Close the static route.
How OSPF adds RIP routes
When the MultiVoice Gateway establishes an IP routing connection with a caller that does not
support OSPF, it imports the AS-external route from the Connection profile and adds it to the
routing table. The MultiVoice Gateway does not have to run RIP to learn these routes. RIP
should be turned off when the MultiVoice Gateway is running OSPF.
To enable OSPF to add the RIP-v2 routes to its routing table, configure RIP-v2 normally in the
Connection profile. OSPF will import all RIP routes as Type-2 ASEs. The reason that RIP
routes are imported with Type-2 metrics by default is that RIP metrics are not directly
comparable to OSPF metrics. To prevent OSPF from interpreting RIP metrics, the imported
ASE route is assigned a Type-2 metric, which means that it is so large compared to OSPF costs
that the metric can be ignored.
Route preferences
Route preferences provide additional control over which types of routes take precedence over
others. They are necessary in a router that supports multiple routing protocols, largely because
RIP metrics are not comparable with OSPF metrics.
For each IP address and subnet-mask pair, the routing table holds one route per protocol, where
the protocols are assigned preferences as follows:
• Connected routes, such as Ethernet, have Preference=0.
• Routes learned from ICMP Redirects have Preference=30.
• Routes placed in the table by SNMP MIB II have Preference=100.
• Routes learned from OSPF have a default of Preference=10. You can modify the default in
Ethernet > Mod Config > Route Pref.
• Routes learned from RIP have a default of Preference=100. You can modify the default in
Ethernet > Mod Config > Route Pref.