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Cisco OSPF Command and Configuration Handbook: Route redistribution

This chapter excerpt focuses on route redistribution commands, including concrete examples and diagrams.

Cisco OSPF Command and Configuration Handbook

Chapter 14, Route Redistribution

This excerpt is reprinted with permission from Cisco Press. For more information or to order the book, visit the Cisco Press Web site.

This chapter includes the following sections:
14-1: redistribute routing-process process-id

14-2: redistribute routing-process process-id metric

14-3: redistribute routing-process process-id metric-type

14-4: redistribute routing-process process-id> subnets

14-5: redistribute routing-process process-id tag

Syntax Description:

  • routing-process -- Routing process to redistribute into OSPF. The routing process can be BGP, Connected, EGP, EIGRP, IGRP, ISIS, ISO-IGRP, Mobile, ODR, OSPF, RIP, or Static.
  • process-id -- The process ID of the routing process (if applicable).
  • ospf-metric -- The metric or cost to assign to the redistributed routes. If this option is not used, a default metric of 1 will be used for redistributed BGP routes and a default metric of 20 will be used for all other protocols. The range of values is 0 to 16,777,214.
  • metric-type -- Routes are redistributed into OSPF as either type 1 or type 2 routes. The default is type 2.
  • tag-value -- A 32-bit value that is attached to the redistributed routes. The route tag is not used by OSPF but can be referenced in a route map for making policy decisions. One possible use is to base the decision to redistribute a route based on the route tag (see Section 14-6). The default tag value is 0. The range of values for the tag is 0 to 4,294,967,295.

Purpose: To redistribute routes learned from another routing process into OSPF. Redistributed routes become OSPF external type 2 routes by default. The default cost or metric of a redistributed route is 1 for BGP and 20 for all other protocols. This command will redistribute classful routes into OSPF only if the subnets keyword is not used. There are three general types of classful routes:

  • A Class A address with an 8-bit subnet mask
  • A Class B address with a 16-bit subnet mask
  • A Class C address with a 24-bit subnet mask

Initial Cisco IOS Software Release: 10.0

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