© 2008 Cisco Systems, Inc. All rights reserved. Cisco ConfidentialBSCI 1 BSCI Module 3 Lesson 2 - Review of OSPF Operation OSPF © 2008 Cisco Systems, Inc. All rights reserved.BSCI 2 CCNP – BSCI Bachkhoa Networking Academy Học viện mạng Bách Khoa - www.bkacad.com Objective OSPF Packet Types OSPF Packet Header Format Establishing OSPF Neighbor Adjacencies Exchanging and Synchronizing LSDBs Discovering the Network Routes Maintaining Network Routes Maintaining Link-State Sequence Numbers Verifying Packet Flow © 2008 Cisco Systems, Inc. All rights reserved.BSCI 3 CCNP – BSCI Bachkhoa Networking Academy Học viện mạng Bách Khoa - www.bkacad.com OSPF Packet Formats All OSPF packets begin with a 24-octet header © 2008 Cisco Systems, Inc. All rights reserved.BSCI 4 CCNP – BSCI Bachkhoa Networking Academy Học viện mạng Bách Khoa - www.bkacad.com OSPF Packet Types Version is the OSPF version number. Type specifies the packet type following the header. Packet length is the length of the OSPF packet, in octets, including the header. Router ID is the ID of the originating router. Area ID is the area from which the packet originated. AuType is the authentication mode being used. Authentication is the information necessary for the packet to be authenticated by whatever mode is specified in the AuType field. © 2008 Cisco Systems, Inc. All rights reserved.BSCI 5 CCNP – BSCI Bachkhoa Networking Academy Học viện mạng Bách Khoa - www.bkacad.com OSPF Packet Types © 2008 Cisco Systems, Inc. All rights reserved.BSCI 6 CCNP – BSCI Bachkhoa Networking Academy Học viện mạng Bách Khoa - www.bkacad.com OSPF Packet Header Format 2 or 3 5 type _____ ______ _____ _____ 3 type •No au •Cle tx •MD5 pass © 2008 Cisco Systems, Inc. All rights reserved.BSCI 7 CCNP – BSCI Bachkhoa Networking Academy Học viện mạng Bách Khoa - www.bkacad.com The Hello Packet The Hello packet establishes and maintains adjacencies. The Hello carries parameters on which neighbors must agree in order to form an adjacency. © 2008 Cisco Systems, Inc. All rights reserved.BSCI 8 CCNP – BSCI Bachkhoa Networking Academy Học viện mạng Bách Khoa - www.bkacad.com The Database Description Packet The Database Description packet is used when an adjacency is being established (see "Building an Adjacency," earlier in this chapter). The primary purpose of the DD packet is to describe some or all of the LSAs in the originator's database so that the receiver can determine whether it has a matching LSA in its own database. This is done by listing only the headers of the LSAs. © 2008 Cisco Systems, Inc. All rights reserved.BSCI 9 CCNP – BSCI Bachkhoa Networking Academy Học viện mạng Bách Khoa - www.bkacad.com The Link State Request Packet As Database Description packets are received during the database synchronization process, a router will take note of any listed LSAs that are not in its database or are more recent than its own LSA. These LSAs are recorded in the Link State Request list. The router will then send one or more Link State Request packets asking the neighbor for its copy of the LSA. © 2008 Cisco Systems, Inc. All rights reserved.BSCI 10 CCNP – BSCI Bachkhoa Networking Academy Học viện mạng Bách Khoa - www.bkacad.com The Link State Update Packet The Link State Update packet, is used in the flooding of LSAs and to send LSAs in response to Link State Requests. [...]... different OSPF packet types 3. 2.2 Drag and Drop: OSPF Packet Header –Upon completion of this activity, the student will be able to identify the different fields in an OSPF packet header 3. 2.5 Drag and Drop: OSPF States –Upon completion of this activity, the student will be able to list in order the different states of OSPF 3. 2.5 Drag and Drop: OSPF Neighbor States –Upon completion of this activity,... the different OSPF neighbor states 3. 2.6 Drag and Drop: OSPF Operation –Upon completion of this activity, the student will be able to list the steps of OSPF operation 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 List 5 types of OSPF packets 2 Which router will be Master 3 Meaning of Sequence Number... flooding of LSAs reliable Each LSA received by a router from a neighbor must be explicitly acknowledged in a Link State Acknowledgment packet BSCI © 2008 Cisco Systems, Inc All rights reserved Học viện mạng Bách Khoa - www.bkacad.com 11 CCNP – BSCI Bachkhoa Networking Academy Establishing OSPF Neighbor Adjacencies Highest IP loopback then physical 10S&40s or 30 s&120s RID of neighbor Area 0 or Area # 0 0-2 55... Maintaining Link-State Sequence Numbers BSCI © 2008 Cisco Systems, Inc All rights reserved Học viện mạng Bách Khoa - www.bkacad.com 18 CCNP – BSCI Bachkhoa Networking Academy Verifying Packet Flow BSCI © 2008 Cisco Systems, Inc All rights reserved Học viện mạng Bách Khoa - www.bkacad.com 19 CCNP – BSCI Bachkhoa Networking Academy Activity 3. 2.1 Drag and Drop: OSPF Packet Types –Upon completion of this activity,... Khoa - www.bkacad.com 21 CCNP – BSCI Bachkhoa Networking Academy Summary OSPF Packet Types OSPF Packet Header Format Establishing OSPF Neighbor Adjacencies Exchanging and Synchronizing LSDBs Discovering the Network Routes Maintaining Network Routes Maintaining Link-State Sequence Numbers Verifying Packet Flow BSCI © 2008 Cisco Systems, Inc All rights reserved Học viện mạng Bách Khoa -. .. 0 0-2 55 [1] IP of DR in Multiple Access environment None or Password or Hash Stub, nssa … (Later) BSCI © 2008 Cisco Systems, Inc All rights reserved Học viện mạng Bách Khoa - www.bkacad.com 12 CCNP – BSCI Bachkhoa Networking Academy Elect DR/BDR BSCI © 2008 Cisco Systems, Inc All rights reserved Học viện mạng Bách Khoa - www.bkacad.com 13 CCNP – BSCI Bachkhoa Networking Academy Link-State Database... Bachkhoa Networking Academy Link-State Database Synchronization BSCI © 2008 Cisco Systems, Inc All rights reserved Học viện mạng Bách Khoa - www.bkacad.com 14 CCNP – BSCI Bachkhoa Networking Academy Exchanging and Synchronizing LSDBs On nonbroadcast multiaccess (NBMA), point-to-multipoint, and virtual links, the hello packets are sent in unicast packets Note After a DR and BDR are selected, any router added... rights reserved Học viện mạng Bách Khoa - www.bkacad.com 15 CCNP – BSCI Bachkhoa Networking Academy Discovering the Network Routes BSCI © 2008 Cisco Systems, Inc All rights reserved Học viện mạng Bách Khoa - www.bkacad.com 16 CCNP – BSCI Bachkhoa Networking Academy Maintaining Network Routers BSCI © 2008 Cisco Systems, Inc All rights reserved Học viện mạng Bách Khoa - www.bkacad.com 17 CCNP – BSCI Bachkhoa... 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 BSCI © 2008 Cisco Systems, Inc All rights reserved Bachkhoa Networking Academy Học viện mạng Bách Khoa - www.bkacad.com 24 . ConfidentialBSCI 1 BSCI Module 3 Lesson 2 - Review of OSPF Operation OSPF © 2008 Cisco Systems, Inc. All rights reserved.BSCI 2 CCNP – BSCI Bachkhoa Networking Academy Học viện mạng Bách Khoa - www.bkacad.com Objective . identify the different OSPF neighbor states. 3. 2.6 Drag and Drop: OSPF Operation –Upon completion of this activity, the student will be able to list the steps of OSPF operation. . Bách Khoa - www.bkacad.com Activity 3. 2.1 Drag and Drop: OSPF Packet Types –Upon completion of this activity, the student will be able to identify the different OSPF packet types. 3. 2.2 Drag