© 2008 Cisco Systems, Inc. All rights reserved. Cisco ConfidentialBSCI 1 BSCI Module 3 Lesson 3 - Implementing and Verifying OSPF 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 Basic Single-Area and Multiarea OSPF Configuring Basic Single-Area OSPF Example Configuring Basic Multiarea OSPF Example Configuring a Router ID Verifying the OSPF Router ID Verifying the OSPF Operation Example of the show ip route ospf Command Example of the show ip ospf interface Command Example of the show ip ospf neighbor Command clear and debug Commands © 2008 Cisco Systems, Inc. All rights reserved.BSCI 3 CCNP – BSCI Bachkhoa Networking Academy Học viện mạng Bách Khoa - www.bkacad.com router ospf process-id [vrf vpn-name] Router(config)# Enable one or more OSPF routing processes. Configuring Basic Single-Area and Multiarea OSPF network ip-address wildcard-mask area area-id Router(config-router)# Define the interfaces that OSPF will run on. Router(config-if)# ip ospf process-id area area-id [secondaries none] Optional method to enable OSPF explicitly on an interface. © 2008 Cisco Systems, Inc. All rights reserved.BSCI 4 CCNP – BSCI Bachkhoa Networking Academy Học viện mạng Bách Khoa - www.bkacad.com Configuring Basic Single-Area OSPF Example Note The network statement and wildcard mask are not used for route summarization purposes. The network statement is used strictly to turn OSPF on for an interface or for multiple interfaces. © 2008 Cisco Systems, Inc. All rights reserved.BSCI 5 CCNP – BSCI Bachkhoa Networking Academy Học viện mạng Bách Khoa - www.bkacad.com Configuring Basic Multiarea OSPF Example © 2008 Cisco Systems, Inc. All rights reserved.BSCI 6 CCNP – BSCI Bachkhoa Networking Academy Học viện mạng Bách Khoa - www.bkacad.com OSPF Router ID The router is known to OSPF by the OSPF router ID number. LSDBs use the OSPF router ID to differentiate one router from the next. By default, the router ID is the highest IP address on an active interface at the moment of OSPF process startup. –If no interface is up when the OSPF process starts, you will get the following error message: –p5r2(config)#router ospf 1 –2w1d: %OSPF-4-NORTRID: OSPF process 1 cannot start. A loopback interface can override the OSPF router ID. If a loopback interface exists, the router ID is the highest IP address on any active loopback interface. The OSPF router-id command can be used to override the OSPF router ID. Using a loopback interface or a router-id command is recommended for stability. © 2008 Cisco Systems, Inc. All rights reserved.BSCI 7 CCNP – BSCI Bachkhoa Networking Academy Học viện mạng Bách Khoa - www.bkacad.com Loopback interface in OSPF © 2008 Cisco Systems, Inc. All rights reserved.BSCI 8 CCNP – BSCI Bachkhoa Networking Academy Học viện mạng Bách Khoa - www.bkacad.com router-id ip-address This command is configured under the router ospf [process- id] command. Any unique arbitrary 32-bit value in an IP address format (dotted decimal) can be used. If this command is used on an OSPF process that is already active, then the new router ID takes effect after the next reload or after a manual restarting of the OSPF process using: OSPF router-id Command Router(config-router)# Router(config)#router ospf 1 Router(config-router)#router-id 172.16.1.1 Router#clear ip ospf process Router#clear ip ospf process © 2008 Cisco Systems, Inc. All rights reserved.BSCI 9 CCNP – BSCI Bachkhoa Networking Academy Học viện mạng Bách Khoa - www.bkacad.com Verifying the OSPF Router ID © 2008 Cisco Systems, Inc. All rights reserved.BSCI 10 CCNP – BSCI Bachkhoa Networking Academy Học viện mạng Bách Khoa - www.bkacad.com Verifying the OSPF Router ID [...]... BSCI Bachkhoa Networking Academy Verifying the OSPF Operation BSCI © 2008 Cisco Systems, Inc All rights reserved Học viện mạng Bách Khoa - www.bkacad.com 11 CCNP – BSCI Bachkhoa Networking Academy Example of the show ip route ospf Command Use the show ip route ospf command to verify the OSPF routes in the IP routing table In Figure , the O code represents OSPF routes, and IA is ―interarea.‖ The 10.2.1.0... Khoa - www.bkacad.com 17 CCNP – BSCI Bachkhoa Networking Academy OSPF Cost ip cost Interface Command –Trinity(config)#int fastethernet0/0 –Trinity(config-if)#ip ospf cost ? Cost Changing the Reference Bandwidth The auto-cost reference-bandwidth ref-bw command is set under the OSPF routing process The default reference bandwidth is 100, but this value is in Mbps, so in this case, 100 is... command: Router#clear ip route * To clear a specific route from the IP routing table, use the following command: Router#clear ip route A.B.C.D BSCI © 2008 Cisco Systems, Inc All rights reserved Học viện mạng Bách Khoa - www.bkacad.com 16 CCNP – BSCI Bachkhoa Networking Academy OSPF Cost The default value for OSPF metrics (cost) is based on bandwidth The following characteristics show how OSPF. .. The entry [110/782] represents the administrative distance assigned to OSPF (110), and the total cost of the route to subnet 10.2.1.0 (782) BSCI © 2008 Cisco Systems, Inc All rights reserved Học viện mạng Bách Khoa - www.bkacad.com 12 CCNP – BSCI Bachkhoa Networking Academy Example of the show ip ospf interface Command The show ip ospf interface [type number] [brief] BSCI © 2008 Cisco Systems, Inc All... the show ip ospf neighbor Command The show ip ospf neighbor [type number] [neighborid] [detail] BSCI © 2008 Cisco Systems, Inc All rights reserved Học viện mạng Bách Khoa - www.bkacad.com 14 CCNP – BSCI BSCI © 2008 Cisco Systems, Inc All rights reserved Bachkhoa Networking Academy Học viện mạng Bách Khoa - www.bkacad.com 15 CCNP – BSCI Bachkhoa Networking Academy clear and debug Commands To clear... are generated: –Each link is given a metric value based on its bandwidth –The metric for a specific link is the inverse of the bandwidth for that link –Link metrics are normalized to give Fast Ethernet a metric of 1 –The metric for a route is the sum of the metrics for all the links in the route Cost = reference bandwidth / interface bandwidth BSCI © 2008 Cisco Systems, Inc All rights reserved Học... limit is 10 seconds) –Token Ring and FDDI are detected immediately –Ethernet is detected after the keepalive packet fails three time BSCI © 2008 Cisco Systems, Inc All rights reserved Học viện mạng Bách Khoa - www.bkacad.com 19 CCNP – BSCI Bachkhoa Networking Academy Hello Timers Hello packets provide the means for OSPF to build adjacencies and monitor (keepalive) adjacent OSPF routers The Hello packet... networks and 120 seconds for nonbroadcast networks BSCI © 2008 Cisco Systems, Inc All rights reserved Học viện mạng Bách Khoa - www.bkacad.com 21 CCNP – BSCI Bachkhoa Networking Academy SPF Timers You can configure the delay time between when OSPF receives a topology change and when it starts an SPF calculation You can also configure the hold time between two consecutive SPF calculations By default, OSPF. .. the many different OSPF configurations is the Cisco white paper, ―Configuring OSPF , which can be downloaded from the Cisco website: http://www.cisco.com/en/US/products/sw/iosswrel/ps18 35/products_configuration_guide_chapter09186a00800 b3f2e.html Configuring OSPF http://www.cisco.com/en/US/products/sw/iosswrel/ ps1828/products_configuration_guide_ chapter09186a00800ca56c.html OSPF Neighbor Problems... networks (Ethernet) and every 30 seconds on nonbroadcast networks (Frame Relay) BSCI © 2008 Cisco Systems, Inc All rights reserved Học viện mạng Bách Khoa - www.bkacad.com 20 CCNP – BSCI Bachkhoa Networking Academy Dead Timers After the dead timer expires, the router assumes that the neighbor is down The dead timer is configured using the ip ospf dead-interval interface configuration command; its syntax . Single-Area and Multiarea OSPF Configuring Basic Single-Area OSPF Example Configuring Basic Multiarea OSPF Example Configuring a Router ID Verifying the OSPF Router ID Verifying the OSPF Operation . Operation Example of the show ip route ospf Command Example of the show ip ospf interface Command Example of the show ip ospf neighbor Command clear and debug Commands © 2008 Cisco Systems, Inc of the show ip route ospf Command Use the show ip route ospf command to verify the OSPF routes in the IP routing table. In Figure , the O code represents OSPF routes, and IA is ―interarea.‖