© 2009 Cisco Systems, Inc. All rights reserved. ROUTE v1.0—3-1 Implementing a Scalable Multiarea Network OSPF- Based Solution Lab 3-3 Debrief

© 2009 Cisco Systems, Inc. All rights reserved. ROUTE v1.0—3-2 Lab Topology

© 2009 Cisco Systems, Inc. All rights reserved. ROUTE v1.0—3-3 Lab Review: What Did You Accomplish?  Task 1: Examining OSPF Routing Information –How can you verify the operation of an OSPF routing protocol? –What can you see by observing the OSPF neighbors, OSPF database, OSPF interfaces, and IP routing table?  Task 2: Summarizing OSPF Internal Routes –How are internal routes defined? –How is summarization performed for internal routes?  Task 3: Summarizing OSPF External Routes –Where do you apply the summarization of external routes? –How many sources of external routes exist in the lab?

© 2009 Cisco Systems, Inc. All rights reserved. ROUTE v1.0—3-4 Verification  Did you have enough information to create an implementation plan?  Were you able to define the OSPF topology and the content of an IP routing table?  Does the summary route exist on the routers in areas 3 and 24?  Does the OSPF link-state database contain relevant information?  Is the routing information for the external networks x.0/24 presented as summary information in the OSPF link-state database and, therefore, in the IP routing tables on relevant routers?  Do all the routers have IP connectivity to the pod external networks?

© 2009 Cisco Systems, Inc. All rights reserved. ROUTE v1.0—3-5 Checkpoints  Examine the IP routing information exchanged by routers configured with the OSPF routing protocol.  Define the internal and external routes.  Configure the summarization of internal routes.  Check if the adjacencies are up.  Check if the IP routing tables and OSPF databases reflect the summarization.  Configure the summarization of external routes.  Check if the adjacencies are up.  Check if the IP routing tables and OSPF databases reflect the summarization.

© 2009 Cisco Systems, Inc. All rights reserved. ROUTE v1.0—3-6 A Sample Solution  The OSPF topology and OSPF operation are verified, along with the IP routing table, which shows the OSPF routes.  Internal summarization is configured for areas 3 and 24 on ABRs.  External summarization is configured on an ASBR router, which redistributes external routes into the OSPF routing protocol.

© 2009 Cisco Systems, Inc. All rights reserved. ROUTE v1.0—3-7 Alternative Solutions  Change the area types in order to optimize the amount of OSPF information entering into a specific area.  Because changing the routing protocol is not a realistic solution, static and default routes can be configured together with route filtering.

© 2009 Cisco Systems, Inc. All rights reserved. ROUTE v1.0—3-8 Q and A  How can you verify OSPF routes in an IP routing table?  How can you verify the OSPF topology and operation?  Where do you perform summarization into areas 3 and 24?  Where do you perform summarization of external routes?  Is there a difference between summarization of internal and external routes?  How can you verify summarization results?

© 2009 Cisco Systems, Inc. All rights reserved. ROUTE v1.0—3-9 Summary  IP routing information exchanged by routers configured with OSPF routing protocol was examined.  You can optimize the OSPF link-state database and consequently the IP routing table by using summarization to making the database smaller.  OSPF routing operation can be further optimized by summarizing OSPF external routes.

© 2009 Cisco Systems, Inc. All rights reserved. ROUTE v1.0—3-10