tailieunhanh - Lecture Routing Protocols and Concepts - Chapter 11: OSPF

Chapter 11 introduce OSPF. This chapter describe the background and basic features of OSPF; identify and apply the basic OSPF configuration commands; describe, modify and calculate the metric used by OSPF; describe the Designated Router/Backup Designated Router (DR/BDR) election process in multiaccess networks; describe the uses of additional configuration commands in OSPF. | OSPF Routing Protocols and Concepts – Chapter 11 Objectives Describe the background and basic features of OSPF. Identify and apply the basic OSPF configuration commands. Describe, modify and calculate the metric used by OSPF. Describe the Designated Router/Backup Designated Router (DR/BDR) election process in multiaccess networks. Describe the uses of additional configuration commands in OSPF. Introduction Introduction to OSPF Background of OSPF Began in 1987 1989 OSPFv1 released in RFC 1131 This version was experimental & never deployed 1991 OSPFv2 released in RFC 1247 1998 OSPFv2 updated in RFC 2328 1999 OSPFv3 published in RFC 2740 Introduction to OSPF OSPF Message Encapsulation OSPF packet type There exist 5 types OSPF packet header Contains - Router ID and area ID and Type code for OSPF packet type IP packet header Contains - Source IP address, Destination IP address, & Protocol field set to 89 Introduction to OSPF OSPF Message Encapsulation Data link frame header Contains - . | OSPF Routing Protocols and Concepts – Chapter 11 Objectives Describe the background and basic features of OSPF. Identify and apply the basic OSPF configuration commands. Describe, modify and calculate the metric used by OSPF. Describe the Designated Router/Backup Designated Router (DR/BDR) election process in multiaccess networks. Describe the uses of additional configuration commands in OSPF. Introduction Introduction to OSPF Background of OSPF Began in 1987 1989 OSPFv1 released in RFC 1131 This version was experimental & never deployed 1991 OSPFv2 released in RFC 1247 1998 OSPFv2 updated in RFC 2328 1999 OSPFv3 published in RFC 2740 Introduction to OSPF OSPF Message Encapsulation OSPF packet type There exist 5 types OSPF packet header Contains - Router ID and area ID and Type code for OSPF packet type IP packet header Contains - Source IP address, Destination IP address, & Protocol field set to 89 Introduction to OSPF OSPF Message Encapsulation Data link frame header Contains - Source MAC address and Destination MAC address Introduction to OSPF OSPF Packet Types Introduction to OSPF Hello Protocol OSPF Hello Packet Purpose of Hello Packet Discover OSPF neighbors & establish adjacencies Advertise guidelines on which routers must agree to become neighbors Used by multi-access networks to elect a designated router and a backup designated router Introduction to OSPF Hello Packets continued Contents of a Hello Packet router ID of transmitting router OSPF Hello Intervals Usually multicast () Sent every 30 seconds for NBMA segments OSPF Dead Intervals This is the time that must transpire before the neighbor is considered down Default time is 4 times the hello interval Introduction to OSPF Hello protocol packets contain information that is used in electing Designated Router (DR) DR is responsible for updating all other OSPF routers Backup Designated Router (BDR) This router takes over DR’s responsibilities if DR fails Introduction to OSPF OSPF Link-state Updates