routing路由v2.0300-1012配置ospf视频课件01introducing the protocol

1、CCNP Route v2.0 (300-101)roducing the OSPF Protocol讲课程黑 眼：90认证：90CCNP Route v2.0 (300-101)OSPF基本概念Open Shortest PathOSPF is a standards-based link-s(OSPF)e IP routing protocol described in RFC 2328.It was developed to meet RIPs inability to scaeyond 15 routers.Proed by IETF in 1988 and formalized in

2、 1991.There are 2 vers; OSPFv2 is for IPv4 and OSPFv3 is for IPv6.OSPF Feature89 - OSPF6 - TCP17 - UDPC R CFrameHeaderOSPF个状态议依赖于IP数据包来传送路由信息使用IP协议号 89仅支持IP环境支持等价负载均衡Frame PayloadPacket PayloadIP Headrotocolumber链路状态路由选择协议R6R3R1R2拓由邻SPFAlgorithmShortest PathTree链路状态协议传递的是链路状态消息的传递采用状态消息，距离矢量传递的是条。的方

3、式传递(距离矢量是定期泛洪整个路由表).链路状态路由协议由邻 表,拓据 ,的.表三张表Comparing OSPF and EIGRPOSPFEIGRP列出所有的邻居列出所有的邻居网络的地图区域内的链路状态邻居的路由表DUALSPF运算路由转Route forwarding路由转Routeforwarding邻居表Link-Se Data StructuresNeighbor table:Also known as the adjacency databaseContains list of recognized neighbors Topology table:Typically refer

4、red to as LSDBContains all routers and their attached linksIdentical LSDB for all routers within an areahe area or networkRouting table:Commonly named a forwarding databaseContains list of best paths to destinationsOSPF AreasExternal RoutingHOSPF areacharacteristics:Minimizes routing table entriesLo

5、calizes impact of a topology change within an areaDetailed LSA flooding stops at the area boundaryRequires a hierarchical network designBackbone AreaABCDEArea 1Area 3FGMArea 2Autonomous SystemLink-Se Data Structure: Network HierarchyLink-se routing requires a hierachical network structuret is enforc

6、ed by OSPF.This two-level hierarchy consists of the following: Transit area (backbone or area 0) Regular areas (nonbackbone areas)Area TerminologyExternal RoutingHRouters A and B are backbone routers.Backbone routers make up area 0.Routers C, D, and E are known as area border routers (ABRs).ABRs att

7、ach all other areas to area 0.Backbone AreaABCDEArea 1Area 3FGMArea 2Autonomous SystemCCNP Route v2.0 (300-101)SPF算法简介OSPF Calculation链路状态路由协议算法Routers find the best paths to destinations by applying Dijkstras SPFalgorithm to the link-se database as follows:Every router in an area has the identical

8、link-se database.Each routerhe area plaitselfo the root of the treet is built.The best path is calculated with respect to the lowest total cost of links to a specific destination.Best routes are puto the forwarding database (routing table).Link-Se Routing ProtocolsLink-se routers recognize more info

9、rmation about the networkn their distancevector countarts.Each router has a full picture of the topology.Consequently, link-se routers tend to make more accurate decis.链路状态路由协议算法每个路由器自己的连接的链路信息和状态，表示自己和哪些路由器连接，到某个路由器或网络的cost(开销)多大，最初只知道自己的一点点局部的拓扑信息LspBRLspARLspERRLRspDLspC链路状态路由协议算法通过可靠的扩散算法各路由器将其它路由器扩散来的拓扑信息收集起来，组成一张一致的、完整的拓扑图，依靠SPF算法来计算出自己的路由表。A的BC数态状态LspALspALspBRLspBRLspALspBRRRRLspELspELspERRRRRLspC RLspC RRLspDLspDLspDRLspCD的状态E的状态LspALspALspBRLspBRRRLspELspERRRLspC RLspC RLspD链路状态路由协议算法1LSDB1AB2LSA 的 RTARTARTB52052CL