© 2008 Cisco Systems, Inc. All rights reserved. Cisco ConfidentialBSCI 1 BSCI Module 3 Lesson 7 - Stub, Totally Stubby, and Not-So-Stubby Areas OSPF © 2008 Cisco Systems, Inc. All rights reserved.BSCI 2 CCNP – BSCI Bachkhoa Networking Academy Học viện mạng Bách Khoa - www.bkacad.com Objective  Configuring OSPF Area Types  Using Stub and Totally Stubby Areas  Configuring Stub Area  OSPF Stub Area Configuration Example  Configuring Totally Stub Areas  Totally Stubby Area Configuration Example  Interpreting Routing Tables  Configuring Not-So-Stubby Areas  Configuring Not-So-Stubby Area Example  Configuring an NSSA Totally Stubby Area Example  Verifying All Stub Area Types © 2008 Cisco Systems, Inc. All rights reserved.BSCI 3 CCNP – BSCI Bachkhoa Networking Academy Học viện mạng Bách Khoa - www.bkacad.com Configuring OSPF Area Types  Standard area: Accepts link updates, route summaries, and external routes (the default). © 2008 Cisco Systems, Inc. All rights reserved.BSCI 4 CCNP – BSCI Bachkhoa Networking Academy Học viện mạng Bách Khoa - www.bkacad.com Configuring OSPF Area Types © 2008 Cisco Systems, Inc. All rights reserved.BSCI 5 CCNP – BSCI Bachkhoa Networking Academy Học viện mạng Bách Khoa - www.bkacad.com Using Stub and Totally Stubby Areas © 2008 Cisco Systems, Inc. All rights reserved.BSCI 6 CCNP – BSCI Bachkhoa Networking Academy Stub Area  A stub area is an area into which AS External LSAs are not flooded. And if type 5 LSAs are not known inside an area, type 4 LSAs are unnecessary; these LSAs are also blocked  As in any area, all routers in a stub area must have identical link- state databases. To ensure this condition, all stub routers will set a flag (the E-bit) in their Hello packets to zero.  No router within a stub area can be an ASBR.  Virtual links cannot be configured within, nor transit, a stub area. Học viện mạng Bách Khoa - www.bkacad.com © 2008 Cisco Systems, Inc. All rights reserved.BSCI 7 CCNP – BSCI Bachkhoa Networking Academy Học viện mạng Bách Khoa - www.bkacad.com Configuring Stub Area © 2008 Cisco Systems, Inc. All rights reserved.BSCI 8 CCNP – BSCI Bachkhoa Networking Academy Học viện mạng Bách Khoa - www.bkacad.com OSPF Stub Area Configuration Example © 2008 Cisco Systems, Inc. All rights reserved.BSCI 9 CCNP – BSCI Bachkhoa Networking Academy Totally Stub Areas  The totally stubby area is a Cisco proprietary enhancement that further reduces the number of routes in the routing table.  A totally stubby area blocks external type 5 LSAs and summary type 3 and 4 LSAs (interarea routes) from entering the area.  Totally stubby areas use a default route to reach not only destinations external to the autonomous system but also all destinations external to the area. Học viện mạng Bách Khoa - www.bkacad.com © 2008 Cisco Systems, Inc. All rights reserved.BSCI 10 CCNP – BSCI Bachkhoa Networking Academy Học viện mạng Bách Khoa - www.bkacad.com Configuring Totally Stub Areas [...]... Networking Academy Activity  3.7.1 Drag and Drop: ID the Area –Upon completion of this activity, the student will be able to identify the difference between stub and totally stubby areas in OSPF BSCI © 2008 Cisco Systems, Inc All rights reserved Học viện mạng Bách Khoa - www.bkacad.com 20 CCNP – BSCI Bachkhoa Networking Academy Self Check 1 Stub vs Totally Stub 2 NSSA vs totally NSSA 3 How to advertise default-route... Bachkhoa Networking Academy Configuring Not-So-Stubby Areas BSCI © 2008 Cisco Systems, Inc All rights reserved Học viện mạng Bách Khoa - www.bkacad.com 14 CCNP – BSCI Bachkhoa Networking Academy Configuring Not-So-Stubby Areas BSCI © 2008 Cisco Systems, Inc All rights reserved Học viện mạng Bách Khoa - www.bkacad.com 15 CCNP – BSCI Bachkhoa Networking Academy Configuring Not-So-Stubby Area Example  To cause... default-information-originate option of the area area-id nssa command on router 2 BSCI © 2008 Cisco Systems, Inc All rights reserved Học viện mạng Bách Khoa - www.bkacad.com 16 CCNP – BSCI Bachkhoa Networking Academy Configuring an NSSA Totally Stubby Area Example  A single default route replaces both inbound-external (type 5) LSAs and summary (type 3 and 4) LSAs into the area.The NSSA ABR, which is router... Networking Academy Totally Stubby Area Configuration Example BSCI © 2008 Cisco Systems, Inc All rights reserved Học viện mạng Bách Khoa - www.bkacad.com 11 CCNP – BSCI Bachkhoa Networking Academy Interpreting Routing Tables BSCI © 2008 Cisco Systems, Inc All rights reserved Học viện mạng Bách Khoa - www.bkacad.com 12 CCNP – BSCI Bachkhoa Networking Academy Configuring Not-So-Stubby Areas BSCI © 2008... www.bkacad.com 22 CCNP – BSCI Bachkhoa Networking Academy Q and A BSCI © 2008 Cisco Systems, Inc All rights reserved Học viện mạng Bách Khoa - www.bkacad.com 23 CCNP – BSCI Bachkhoa Networking Academy Resources  How Does OSPF Generate Default Routes? –http://www.cisco.com/en/US/tech/tk365/technologies_tech_not e09186a0080094a74.shtml  OSPF Not-So-Stubby Area (NSSA) –http://www.cisco.com/en/US/tech/tk365/technologies_tech_not . Systems, Inc. All rights reserved. Cisco ConfidentialBSCI 1 BSCI Module 3 Lesson 7 - Stub, Totally Stubby, and Not-So-Stubby Areas OSPF © 2008 Cisco Systems, Inc. All rights reserved.BSCI 2 CCNP. Configuring OSPF Area Types  Using Stub and Totally Stubby Areas  Configuring Stub Area  OSPF Stub Area Configuration Example  Configuring Totally Stub Areas  Totally Stubby Area Configuration. Configuration Example  Interpreting Routing Tables  Configuring Not-So-Stubby Areas  Configuring Not-So-Stubby Area Example  Configuring an NSSA Totally Stubby Area Example  Verifying All Stub Area