开放链路最短优先 pen Shortest Path First I Cisco.com 深圳职业技术学院计算机系网络专业 006,Shenzhen Polytechnic.All rights reserved
© 2006, Shenzhen Polytechnic. All rights reserved. 1 开放链路最短优先 Open Shortest Path First 深圳职业技术学院计算机系网络专业
链路状态协议(Link-State Protocols) 夏 Cisco.com ◇ D Link-State Advertisement(LSA) Link-State Database SPF Algorithm Routing Table Shortest Path First(SPF)Tree 006ShenzhenPolytechnic.All rightsreserved
© 2006 Shenzhen Polytechnic. All rights reserved. 2 链路状态协议（Link-State Protocols）
OSPF概述(OSPF Overview) mwmwmwt Cisco.com 面
© 2006 Shenzhen Polytechnic. All rights reserved. 3 OSPF概述（OSPF Overview）
分层设计(Hierarchical Design) Cisco.com 1.大的OSPF网络采用分层设计，所有区域连接到主干区域 Large OSPF networks use a hierarchical design. Multiple areas connect to a distribution area,area 0, also called the backbone. 2.好处（benefit): (1)减少路由更新(reduces routing overhead) (2)加速收敛(speeds up convergence) (3)限制不稳定到一个区域(confines network instability to an area (4)提高网络性能(improves performance)
© 2006 Shenzhen Polytechnic. All rights reserved. 4 分层设计（Hierarchical Design ） 1.大的OSPF网络采用分层设计，所有区域连接到主干区域 。 Large OSPF networks use a hierarchical design. Multiple areas connect to a distribution area, area 0, also called the backbone. 2.好处（benefit）： （1）减少路由更新（reduces routing overhead） （2） 加速收敛（speeds up convergence） （3）限制不稳定到一个区域（confines network instability to an area ） （4）提高网络性能（improves performance）
OSPF术语(OSPF Terminology) wmm Cisco.com 1 OSPF Terminology 2 Roll over numbers 3 to view terms and Area0 definitions. Links 4 Area 1 DR Link-state 5 Cost 10 6 Token Ring Cost=1785 Cost =6 BDR Adjacencies Topological Routing 9 Database Database Table
© 2006 Shenzhen Polytechnic. All rights reserved. 5 OSPF术语（OSPF Terminology）
OSPF数据包类型(OSPF Packet Types) WWWI Cisco.com 个Hello 2 Database Description 3 Link-State Request Link-State Update 5 Link-State Acknowledgement
© 2006 Shenzhen Polytechnic. All rights reserved. 6 OSPF数据包类型（OSPF Packet Types）
OSPF数据包头格式 (OSPF Packet Header Format) wwm Cisco.com Link OSPF Link Header Header Packet Trailer Types Protocol ID No. 89=OSPF OSPF Packet Version Packet Authen- Router ID Check- Number Type Length Area ID Sum tication Authen-Data Type tication
© 2006 Shenzhen Polytechnic. All rights reserved. 7 OSPF数据包头格式 （OSPF Packet Header Format）
OSPF操作(OSPF Operation) Cisco.com 1.建立邻接关系 Establish router adjacencies 2.必要的进行DR选举 Elect the DR/BDR(if necessary 3.发现路由 Discover routes 4.选择相应的路由 Select appropriate routes 5.维护路由信息 Maintain routing information 2006 Shenzhen Polytechnic.All rightsres
© 2006 Shenzhen Polytechnic. All rights reserved. 8 OSPF操作（OSPF Operation） 1. 建立邻接关系 Establish router adjacencies 2. 必要的进行DR选举 Elect the DR / BDR ( if necessary ) 3. 发现路由 Discover routes 4.选择相应的路由 Select appropriate routes 5. 维护路由信息 Maintain routing information
邻居关系(Neighborship) wmmm Cisco.com Hello A Router ID 39547439070713 Hello/dead intervals Router priority Hello RPdr Authentication password Stub area flag Entry must match on neighboring routers o2ooss劲Polytochnic.Allrightor*标记的在邻居路由器上必须匹配
© 2006 Shenzhen Polytechnic. All rights reserved. 9 邻居关系（Neighborship） *标记的在邻居路由器上必须匹配
建立双向通信 (Establishing Bidirectional Communication) AIIIE Cisco.com 172.16.5.1/24 172.16.5.2/24 E1 B Down State
© 2006 Shenzhen Polytechnic. All rights reserved. 10 建立双向通信 （Establishing Bidirectional Communication）