Cisco Systems CL-28826-01 Redistributing Routes into OSPF

64-22

User Guide for Cisco Security Manager 4.4

OL-28826-01

Chapter 64 Configuring Routing Policies

OSPF Routing on Cisco IOS Routers

•Specifying clear-text authentication for an area sets the authentication to Type 1 (simple password).

All routers on a network must use the same clear-text password to communicate with each other

using OSPF.

•MD5 passwords need not be the same throughout an area, but they must be the same between

neighbors.

•If you use interface authentication (see Defining OSPF Interface Settings, page 64-25), the

authentication type used for the area must match the authentication type used for the interface.

Step 7 Click OK to save your definitions. The OSPF area appears in the table displayed on the OSPF Area tab.

Redistributing Routes into OSPF

Redistribution refers to using a routing protocol, such as OSPF, to advertise routes that are learned by

some other means, such as a different routing protocol, static routes, or directly connected routes. For

example, you can redistribute routes from the RIP routing protocol into your OSPF domain.

Redistribution is necessary in networks that operate in multiple-protocol environments and can be

applied to all IP-based routing protocols.

Redistributing routes into OSPF from other routing protocols or from static routes causes these routes

to become OSPF external routes (Type 1 or Type 2).

Redistributing routes into OSPF involves:

•Defining OSPF Redistribution Mappings, page 64-22

•Defining OSPF Maximum Prefix Values, page64-23

When you define OSPF redistribution mappings, you must select the protocol to redistribute and the

OSPF process into which routes from that protocol are redistributed. Additionally, you can manually

define the metric, which determines the priority of the redistributed routes, and the type of external OSPF

route to create, Type 1 or Type 2.

You can create multiple mappings to the same OSPF process. For example, you can redistribute both RIP

and EIGRP routes into the same OSPF process. You can also redistribute routes from other OSPF

processes.

Note Redistribution into an OSPF Not-So-Stubby Area (NSSA) creates a special type of link-state

advertisement (LSA) called type 7, which can exist only in an NSSA area. An NSSA autonomous system

router (ASBR) generates this LSA, and an NSSA area border router (ABR) translates it into a type 5

LSA, which is propagated into the OSPF domain.