routing路由v2.0300-1012配置ospf視頻課件01introducing the protocol

1、CCNP Route v2.0 (300-101)roducing the OSPF Protocol講課程黑 眼：90認證：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個狀態(tài)議依賴于IP數據包來傳送路由信息使用IP協議號 89僅支持IP環(huán)境支持等價負載均衡Frame PayloadPacket PayloadIP Headrotocolumber鏈路狀態(tài)路由選擇協議R6R3R1R2拓由鄰SPFAlgorithmShortest PathTree鏈路狀態(tài)協議傳遞的是鏈路狀態(tài)消息的傳遞采用狀態(tài)消息，距離矢量傳遞的是條。的方

3、式傳遞(距離矢量是定期泛洪整個路由表).鏈路狀態(tài)路由協議由鄰 表,拓據 ,的.表三張表Comparing OSPF and EIGRPOSPFEIGRP列出所有的鄰居列出所有的鄰居網絡的地圖區(qū)域內的鏈路狀態(tài)鄰居的路由表DUALSPF運算路由轉Route forwarding路由轉Routeforwarding鄰居表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算法簡介OSPF Calculation鏈路狀態(tài)路由協議算法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.鏈路狀態(tài)路由協議算法每個路由器自己的連接的鏈路信息和狀態(tài)，表示自己和哪些路由器連接，到某個路由器或網絡的cost(開銷)多大，最初只知道自己的一點點局部的拓撲信息LspBRLspARLspERRLRspDLspC鏈路狀態(tài)路由協議算法通過可靠的擴散算法各路由器將其它路由器擴散來的拓撲信息收集起來，組成一張一致的、完整的拓撲圖，依靠SPF算法來計算出自己的路由表。A的BC數態(tài)狀態(tài)LspALspALspBRLspBRLspALspBRRRRLspELspELspERRRRRLspC RLspC RRLspDLspDLspDRLspCD的狀態(tài)E的狀態(tài)LspALspALspBRLspBRRRLspELspERRRLspC RLspC RLspD鏈路狀態(tài)路由協議算法1LSDB1AB2LSA 的 RTARTARTB52052CL